,,machinery',s ,,reference ,,series     
,,each ,,number ,,is ,,one ,,unit ,,in  
,a ,,complete ,,library ,,of ,,machine  
,,design ,,and ,,shop  ,,practice       
,,revised ,,and ,,republished ,,from    
,,machinery    ,,number #ba             
,,measuring ,,tools    ,,third ,,edition
        ,,contents    ,history and      
,development of ,standard ,measurements 
,calipers1 ,dividers1 and ,surface      
,gages    ,micrometer ,measuring        
,instruments    ,miscellaneous          
,measuring ,tools and ,gages            
,copyright1 #aiaj1 ,the ,industrial     
,press1 ,publishers of ,,machinery4     
#di-ee ,lafayette ,street1 ,new ,york   
,city           99       99       99    
99       99      ,,chapter ,i           
,,history ,,and ,,development ,,of      
,,standard ,,measurements#a    ,while   
every mechanic makes use of the         
standards of length every day1 and  uses
 tools graduated according to accepted  
standards when performing even  the     
smallest operation in the shop1 there   

are comparatively few who know  the     
history of the development of the       
standard measurements of length1 or  are
 familiar with the methods employed in  
transferring the measurements  from the 
reference standard to the working       
standards4 ,we shall therefore  here    
give a short review of the history and  
development of standard  measurements of
 length1 as abstracted from a paper read
 by ,mr4 ,w4 ,a4 ,viall  before the     
,providence ,association of ,mechanical 
,engineers4    ,origin of ,standard     
,measurements    ,by examining the ruins
 of the ancients it has been found that 
they had  standard measurements1 not in 
the sense in which we are now to        
consider  them1 but the ruins show that 
the buildings were constructed according
 to  some regular unit4 ,in many1 if not
 all cases1 the unit seems to be some   
part of the human body4 ,the foot1 it is
 thought1 first appeared in  ,greece1   
and the standard was traditionally said 
to have been received from  the foot of 

,hercules1 and a later tradition has it 
that ,charlemagne  established the      
measurement of his own foot as the      
standard for his  country4    ,standards
 ,previous to #ahjj    ,in ,england1    
prior to the conquest1 the yard         
measured1 according to later            
investigations1 #ci4f inches1 but it was
 reduced by ,henry ,i in #aaja1 to      
compare with the measurement of his own 
arm4 ,in #acbd1 under ,edward ,,ii1 it  
was enacted that the inch shall have    
length of three barley corns1 round  and
 dry1 laid end to end2 twelve inches    
shall make one foot1 and three feet  one
 yard4 ,while this standard for         
measurement was the accepted one1       
scientists were at work on a plan to    
establish a standard for length that    
could be recovered if lost1 and         
,huygens1 a noted philosopher and       
scientist  of his day1 suggested that   
the pendulum1 which beats according to  
its  length1 should be used to establish
 the units of measurement4 ,in #ageh    

,parliament appointed a commission to   
investigate and compare the various     
standards with that furnished by the    
,royal ,society4 ,the commission caused 
a  copy of this standard to be made1    
marked it ,standard ,yard1 #ageh1 and   
laid  it before the ,house of ,commons4 
,in #agdb1 members of the ,royal        
,society of  ,england and the ,royal    
,academy of ,science of ,paris agreed to
 exchange  standards1 and two bars #db  
inches long1 with three feet marked off 
upon  them1 were sent to ,paris1 and one
 of these was returned later with ,toise
  marked upon it4 ,in #agfj a yard bar  
was prepared by ,mr4 ,bird1 which was   
afterwards adopted as a standard1 as we 
shall see later4    ,in #aggd the ,royal
 ,society offered a reward of a hundred 
guineas for a  method that would obtain 
an invariable standard1 and ,halton     
proposed a  pendulum with a moving      
weight upon it1 so that by counting the 
beats when  the weight was in one       
position and again when in another1 and 

then  measuring the distance between the
 two positions1 a distance could be     
defined that could at any time be       
duplicated4 ,the ,society paid #cj      
guineas  for the suggestion1 and later  
the work was taken up by ,j4 ,whitehurst
 with  the result that the distance     
between the positions of the weight when
  vibrating #db and #hd times a minute  
was #ei4hiceh inches4 ,the method was   
not  further developed4    ,how the     
,length of the ,meter was ,established  
,in #agij1 ,talleyrand1 then ,bishop of 
,autun1 suggested to the ,constituent   
,assembly that the king should endeavor 
to have the king of ,england request    
his parliament to appoint a commission  
to work in unison with one to be        
appointed in ,france1 the same to be    
composed of members of the ,royal       
,society and ,royal ,academy of         
,science1 respectively1 to determine the
 length  of a pendulum beating seconds  
of time4 ,england did not respond to the
  invitation1 and the ,french commission

 appointed considered first of all      
whether the pendulum beating seconds of 
time1 the quadrant of the meridian1  or 
the quadrant of the equator should be   
determined as a source of the  standard4
 ,it was decided that the quadrant of   
the meridian should be  adopted and that
 #j4jjjjjja of it should be the         
standard4    ,the arc of about nine and 
one-half degrees1 extending from        
,dunkirk on the  ,english ,channel to   
,barcelona on the ,mediterranean and    
passing through  ,paris1 should be the  
one to be measured4 ,the actual work of 
measuring was  done by ,mechain and     
,delambre according to the plans laid   
down by the  commission4 ,mechain was to
 measure about #be per cent of the arc1 
the  southern portion of it1 and        
,delambre the remainder2 the reason for 
this  unequal division was that the     
northern division had been surveyed     
previously1 and the territory was       
well-known1 whereas the southern part   
was  an unknown country1 as far as the  

measurement of it went1 and it was      
expected that many severe difficulties  
would have to be surmounted4 ,the       
,revolution was in progress1 and it was 
soon found that the perils attending    
the measurement of the northern part    
were greater than those attending the   
southern part of the territory4 ,the    
people looked askance at all things     
that they did not understand1 and       
,delambre with his instruments was      
looked  upon as one sent to further     
enthrall them4 ,he was set upon by the  
people at  various times and although   
the authorities endeavored to protect   
him1 it  was only by his own bravery and
 tact that he was able to do his work   
and  save his life4 ,the ,committee of  
,safety ordered that ,mechain and       
,delambre  close their work in #agie1   
and it was some time afterward before it
 was  resumed4    ,having completed the 
field work1 the results of their labors 
were laid  before a commission composed 
of members of the ,national ,institute  

and  learned men from other nations1 who
 had accepted the invitation that had   
been extended to them1 and after        
carefully reviewing and calculating the 
work1 the length of the meridian was    
determined1 and from it was  established
 the meter as we now have it4 ,a        
platinum bar was made according  to the 
figures given1 and this furnishes the   
prototype of the meter of the  present  
time4 ,notwithstanding all of the care  
taken in establishing the  meter1 from  
work done by ,gen4 ,schubert1 of        
,russia1 and ,capt4 ,clarke1 of         
,england1 it has been shown that it is  
not #j4jjjjjja of the quadrant passing  
through ,paris1 but of the one passing  
through ,new ,york4    ,the ,standard   
,yard in ,england--,its ,loss and       
,restoration    ,whether incited by the 
work of the ,french or not1 we do not   
know1 but in  the early part of this    
century the ,english began to do more   
work upon the  establishment of a       
standard1 and in #ahaf a commission was 

appointed by the  crown to examine and  
report upon the standard of length4     
,capt4 ,kater made a  long series of    
careful observations determining the    
second pendulum to be  #ci4achf inches  
when reduced to the level of the sea4   
,this measurement was  made on a scale  
made by ,troughton--who1 by the way1 was
 the first to  introduce the use of the 
microscope in making measurements--under
 the  direction of and for ,sir ,geo4   
,schuckburgh4 ,in #ahbb1 having made    
three  reports1 after many tests1 it was
 recommended that the standard prepared 
by  ,bird in #agfj1 marked ,standard    
,yard1 #agfj1 be adopted as the standard
 for  ,great ,britain4    ,the act of   
,june1 #ahbd1 after declaring that this 
measure should be adopted  as the       
standard1 reads in ,sec4 ,,iii43 ,and   
whereas it is expedient that the        
,standard ,yard1 if lost1 destroyed1    
defaced or otherwise injured should be  
restored to the same length by reference
 to some invariable natural  ,standard2 

and whereas it has been ascertained by  
the ,commissioners  appointed by ,his   
,majesty to inquire into the ,subjects  
of ,weights and  ,measures1 that the    
,yard1 hereby declared to be the        
,imperial ,standard ,yard1  when        
compared with a ,pendulum vibrating     
,seconds of ,mean ,time in the  latitude
 of ,london1 in a ,vacuum at the ,level 
of the ,sea1 is in the  proportion of   
,thirty-six ,inches to ,thirty-nine     
,inches and one thousand  three hundred 
and ninety-three ten thousandth parts of
 an ,inch2 ,be it  enacted and declared1
 that if at any ,time hereafter the said
 ,imperial  ,standard ,yard shall be    
lost1 or shall be in any manner         
destroyed1 defaced  or otherwise        
injured1 it shall and may be restored by
 making a new ,standard  ,yard bearing  
the same proportion to such ,pendulum1  
as aforesaid1 as the  said ,imperial    
,standard ,yard bears to such ,pendulum4
    ,it was not long after this act had 
been passed1 if indeed not before1 that 

it became known that the pendulum method
 was an incorrect one1 as it was  found 
that errors had occurred in reducing the
 length obtained to that at  the sea    
level1 and despite the great pains that 
had been taken1 it is  doubtful if the  
method was not faulty in some of its    
other details4    ,when the ,houses of  
,parliament were burned in #ahcd1 an    
opportunity was  offered to try the     
method upon which so much time and care 
had been spent4  ,a commission was      
appointed and to ,sir ,francis ,baily   
was assigned the task  of restoring the 
standard4 ,he did not live to complete  
the task1 dying in  #ahdd4 ,he succeeded
 in determining the composition of the  
metal that was  best adapted to be used1
 which metal is now known as ,baily's   
metal4    ,rev4 ,r4 ,sheepshanks        
constructed a working model as a        
standard and compared  it with two      
,schuckburg's scales1 the yard of the   
,royal ,society1 and two  iron bars that
 had been used in the ordnance          

department4 ,having determined  to his  
own satisfaction and that of his        
associates the value of the yard1  he   
prepared the standard imperial yard1    
known as ,bronze ,no4 #a1 a bronze bar  
#ch  #a  #a inch1 with two gold plugs   
dropped into holes so that the surface  
of the plugs passes through the center  
plane of the bar4 ,upon these plugs  are
 three transverse lines and two         
longitudinal lines1 the yard being the  
distance from the middle transverse     
line--the portion lying between the two 
longitudinal ones--of one plug1 to the  
corresponding line on the other  plug4  
,forty copies were made1 but two of     
these being correct at #fb degrees      
,fahrenheit1 and these two1 together    
with the original and one other1 are    
kept in ,england as the standards for   
reference4 ,in #ahee the standard as    
made by ,rev4 ,sheepshanks was          
legalized4    ,attempts to ,fix a       
,standard in the ,united ,states    ,the
 ,constitution empowers ,congress to fix

 the standards of weights and  measures1
 but up to #ahff no legal standard      
length had been adopted4 ,in his  first 
message to ,congress ,washington said3  
,a uniformity in the weights and        
measures of the country is among the    
important objects submitted to you by   
the ,constitution1 and if it can be     
derived from a standard at once         
invariable and universal1 it must be no 
less honorable to the public  council   
than conducive to the public            
convenience4    ,in ,july1 #agij1       
,thomas ,jefferson1 then ,secretary of  
,state1 sent a report to  ,congress     
containing two plans1 both based on the 
length of the pendulum1 in  this case   
the pendulum to be a plain bar1 the one 
plan to use the system  then existing1  
referring it to the pendulum as the     
basis1 and the other to  take the       
pendulum and subdivide it1 one-third of 
the pendulum to be called  a foot4 ,the 
whole length was that of one beating    
seconds of time4 ,he made a  table to   

read as follows3      #aj ,points make a
 ,line4    #aj ,lines make a ,foot4     
#aj ,feet make a ,decad4    #aj ,decads 
make a ,rood4    #aj ,roods make a      
,furlong4    #aj ,furlongs make a ,mile4
    ,congress did not adopt his system1 
and as ,england was then working on the 
problem1 it was decided to await the    
results of its labors4 ,in #ahaf1       
,madison1 in his inaugural address1     
brought the matter of standards to the  
attention of ,congress1 and a committee 
of the ,house made a report             
recommending the first plan of          
,jefferson1 but the report was not acted
  upon4 ,in #ahba1 ,j4 ,q4 ,adams1 then 
,secretary of ,state1 made a long and   
exhaustive report in which he favored   
the metric system1 but still advised    
,congress to wait1 and                  
,congress--waited4    ,what the         
,standards are in the ,united ,states   
,the standard of length which had       
generally been accepted as the standard1
  was a brass scale #hb inches long1    

prepared by ,troughton for the ,coast   
,survey of the ,united ,states4 ,the    
yard used was the #cf inches between the
  #bgth and #fc;d inch of the scale4 ,in
 #ahef1 however ,bronze ,no4 #aa was    
presented to the ,united ,states by the 
,british government4 ,this is a         
duplicate of the ,no4 #a ,bronze        
mentioned before1 which is the legalized
  standard yard in ,england4 ,it is     
standard length at #fa4gi degrees ,f41  
and is  the accepted standard in the    
,united ,states4 ,a bar of ,low ,moor   
iron1 ,no4 #eg1  was sent at the same   
time1 and this is correct in length at  
#fb4eh degrees  ,f4 ,the expansion of   
,bronze ,no4 #aa is #j4jjjcdb inch1 and 
that of the iron  bar is #j4jjjbba inch 
for each degree ,fahrenheit4 ,while the 
yard is the  commonly accepted standard 
in this country1 it is not the legal    
standard4  ,in #ahff ,congress passed a 
law making legal the meter1 the first   
and only  measure of length that has    
been legalized by our government4       

,copies of the  meter and kilogram1     
taken from the original platinum bar at 
,paris1 referred  to before1 were       
received in this country by the         
,president and members of  the ,cabinet1
 on ,jan4 #b1 #ahij1 and were deposited 
with the ,coast ,survey4 ,by  formal    
order of the ,secretary of the          
,treasury1 ,april #e1 #ahic1 these were 
denominated the ,fundamental ,standards4
    ,the ,international ,bureau of      
,weights and ,measures    ,after the    
original meter was established1 it was  
found that copies made by  various      
countries differed to a greater or less 
extent from the original1  and believing
 that a copy could be made from which   
other copies could be  more readily made
 than from the end piece meter1 and that
 better provision  could be made for the
 preservation of the standard1 ,france  
called a  convention of representatives 
from various ,states using the system1  
to  consider the matter4 ,the ,united   
,states representatives1 or             

commissioners1  were ,messrs4 ,henry and
 ,hildegard1 who met with the general   
commission in  #ahgj4 ,the commissioners
 at once set at work to solve the       
problem presented  to them1 but the     
,franco-,prussian war put an end to     
their deliberations4 ,the  deliberations
 were resumed later1 and ,may #bj1      
#ahge1 representatives of the  various  
countries signed a treaty providing for 
the establishment and  maintenance1 at  
the common expense of the contracting   
nations1 of a  scientific and permanent 
international bureau of weights and     
measures1 the  location of which should 
be ,paris1 to be conducted by a general 
conference  for weights and measures1 to
 be composed of the delegates of all the
  contracting governments4    ,this     
bureau is empowered to construct and    
preserve the international  standards1  
to distribute copies of the same to the 
several countries1 and  also to discuss 
and initiate measures necessary for the 
determination of  the metric system4    

,the commission adopted a form for the  
standard as shown  in ,fig4 #a4 ,the    
lines representing the length of the    
meter are drawn on the  plane ,a1 which 
is the neutral plane1 and will not      
change in length should  the bar        
deflect4 ,the bar is made of #ij per    
cent platinum and #aj per cent  iridium1
 about #bej kilograms having been melted
 when preparations were made  for the   
first standard1 so that all of the      
copies made from this cast  represent   
the same coefficient of expansion and   
are subject to the same  changes as the 
original4 ,the ,french government       
presented to the bureau the  pavilion   
,breteuil1 opposite the ,park of ,st4   
,cloud1 which was accepted and  put into
 order and is now the repository of the 
originals of the meter and  the         
kilogram4 ,the expense attending the    
first establishment of the bureau  was  
about #aj1jjj to the ,united ,states1   
and since then its share of the  annual 
expense has been about #ijj4 ,the       

standards in the possession of the      
,united ,states were received through   
the international bureau4    ,the       
,commercial ,value of a ,standard       
,having at the disposal of the nation a 
standard of length1 the question        
arises1 ,what can be made of it         
commercially1 and how do we know when we
  have a copy of the standard8          
,illustration3 ,fig4 #a4 ,form of ,bar  
,adopted for ,international ,standards  
of  ,length    ,in #ahic1 the ,brown    
,sharpe ,mfg4 ,co4 decided to make a new
 standard to  replace the one they had  
at that date4 ,mr4 ,o4 ,j4 ,beale was   
detailed to do  this work4 ,he prepared 
steel bars about #dj inches long by #a  
inch square1  and after planing them1   
they were allowed to rest for several   
months4 ,at  the ends of these bars he  
inserted two gold plugs1 the centers of 
which  were about #cf inches apart1 and 
a little beyond these two others about  
one  meter apart4 ,a bar was placed in  
position upon a heavy bed4 ,this was so 

arranged that a tool carrier could be   
passed over the bar4 ,the tool carrier  
consisted of a light framework1 holding 
the marking tool4 ,one feature of  the  
marking was that the point of the       
marking tool was curved and had an      
angle1 so that if dropped it made an    
impression in the form of an ellipse4   
,in graduations1 ordinarily1 the line1  
when highly magnified1 is apt to        
present at its ends an impression less  
definite than in the center1 by  reason 
of the form of the objective4 ,the line 
made with the tool mentioned  is short1 
and that portion of the line is read    
which passes1 apparently1  through the  
straight line in the eye-glass of the   
microscope4 ,in order to  make these    
lines as definite as possible1 the point
 was lapped to a bright  surface4 ,after
 being placed in position1 the          
microscope1 which could be  placed on   
the front of the tool carrier1 was set  
to compare with the  graduation on the  
standard bar from which the new bar was 

to be prepared4  ,after such a setting  
the readings were made by three persons1
 and by  turning the lever the marking  
tool was dropped1 making a very fine    
line1 so  fine indeed1 that when the    
authorities in ,washington began the    
examination  of the bar later on they   
declared that no line had been made upon
 these  studs4    ,after making the     
first line1 the carriage was moved along
 to compare with  the other line on the 
standard1 and after the correction had  
been made by  the use of the micrometer 
in the microscope1 the marking tool was 
again  dropped1 giving the second line1 
which was intended to mark the limit of 
one yard over-all4 ,the same operation  
was repeated in the marking of the      
meter4 ,the whole of this work was done1
 of course1 with the greatest care1     
and1 while the theoretical portion of it
 appears very simple in detail1 it      
required a great deal of time and       
patience before the last line had been  
made4 ,the bar thus marked was taken to 

,washington1 and in ,mr4 ,beale's       
presence was compared by the attendants 
with ,bronze ,no4 #aa and later with    
,low ,moor bar1 ,no4 #eg4    ,in        
comparing this standard1 a method was   
employed very similar to that used  in  
marking it4 ,the bar1 properly          
supported1 was placed upon a box that   
rested upon rolls1 and on this same box 
was placed the government standard  with
 which the ,brown  ,sharpe standard was 
to be compared4 ,the standard was       
placed in position under the microscope1
 and after being properly set to  the   
standard1 the bar to be measured was    
placed under the microscope1 and  by the
 micrometer screw of the microscope the 
variation was measured4 ,three          
comparisons were made by each of the    
attendants on each end before           
determining the reading of the          
microscope1 and after such comparisons  
and  many repetitions of it1 the value  
of the standard ,no4 #b was found to be 
#cf4jjjfa inches for the yard1 and      

#a4jjjjadg meter for the meter4         
,after this work had been done1 ,mr4    
,beale prepared a second standard which 
he called ,no4 #c1 and after examining1 
as shown above1 the error was found  to 
be #j4jjjjb inch for the yard1 and      
#j4jjjjje meter for the meter4          
,observing these variations as compared 
with the standards originally made1  we 
find they are very close1 and it is     
doubtful if many repeated trials  would 
furnish more accurate work1 when we     
remember that out of forty  original    
standards made1 but two are correct at  
#fb degrees ,fahrenheit4    ,after      
establishing a yard1 the problem of     
obtaining an inch comes next1 and  this 
was made by subdividing the yard into   
two equal parts1 these into  three1 and 
the three further subdivided into six   
parts4 ,it should be  particularly noted
 that no mention has been made of a     
standard inch1 as  there is none1 the   
standard yard only existing1 the        
subdivision of which  falls upon those  

undertaking standard work4 ,there is a  
remarkable agreement  between at least  
three leading gage makers of this       
country and abroad1 and  each came to   
the result by its own method of         
subdividing the standard yard4    ,kinds
 of ,measurements and ,measuring ,tools 
,the measurements in the shop may1 in   
general1 be divided into measurements   
of length and measurements of angles4   
,the length measurements in turn may  be
 divided into line measurements and end 
measurements1 the former being  made by 
placing a rule or similar instrument    
against the object being  measured1 and 
comparing its length with the           
graduations on the measuring            
instruments2 the latter are made by     
comparing the object being measured     
with the measuring instrument1 by       
bringing the object measured into actual
  contact with the measuring surfaces of
 the instrument4 ,examples of line      
measurements are the ordinary           
measurements made with the machinist's  

rule1  and examples of end measurement  
are those made by the micrometer1       
measuring  machines1 and snap gages4    
,angular measurements can also be       
divided into two  classes2 those        
measured directly by graduations on the 
instrument1 and  those measured by      
comparison with a given angle of the    
instrument4    ,measuring instruments   
may also be divided into two classes1   
according to  whether they actually are 
used for measuring1 or whether they are 
principally used for comparing objects  
with one another4 ,according to this    
classification all kinds of rules and   
protractors belong to the first  class1 
whereas all gages belong to the second  
class4 ,the ordinary  instruments for   
length measurements1 the regular        
machinists' rule1 the  caliper square1  
and the ordinary micrometer caliper1 are
 too well known to  require any         
additional explanation4 ,the same is    
true of the regular bevel  protractor   
for measuring angles4 ,we shall         

therefore in the following  chapters    
deal principally with special measuring 
tools1 and with such  methods in the use
 of tools which are likely to suggest   
improvements1 or  otherwise be valuable 
to the user and maker of measuring      
tools4           99       99       99   
99       99      ,,chapter ,,ii         
,,calipers1 ,,dividers1 ,,and ,,surface 
,,gages    ,in the present chapter we   
shall deal with the simpler forms of    
tools used  for measuring1 such as      
ordinary calipers1 and their use2       
surface gages2  special attachments for 
scales and squares1 facilitating        
accurate  measuring2 and vernier and    
beam calipers4 ,the descriptions of the 
tools and  methods referred to have     
appeared in ,,machinery from time to    
time4 ,the names  of the persons who    
originally contributed these            
descriptions have been  stated in notes 
at the foot of the pages1 together with 
the month and year  when their          
contribution appeared4    ,setting      

,inside ,calipers    ,illustration3     
,figs4 #b and #c - ,fig4 #d - ,setting  
,inside ,calipers    ,it is customary   
with most machinists1 when setting      
inside calipers to a  scale1 to place   
one end of the scale squarely against   
the face of some true  surface1 and     
then1 placing one leg of the caliper    
against the same surface1  to set the   
other leg to the required measurement on
 the scale4 ,for this  purpose the      
faceplate of the lathe is frequently    
used on account of its  being close at  
hand for the latheman4 ,the sides of the
 jaws of a vise or  almost anything     
located where the light is sufficient to
 read the markings  on the scale are    
frequently used4    ,the disadvantages  
of this method are1 first1 that a rough 
or untrue object  is often chosen1      
particularly if it happens to be in a   
better light than a  smooth and true    
one1 and1 second1 that it is very hard  
to hold the scale  squarely against an  
object4 ,it is easy enough to hold it   

squarely  crosswise1 but it is not so   
easy a matter to keep it square         
edgewise4 ,as  can be readily seen1 this
 makes quite a difference with the      
reading of the  calipers1 particularly  
if the scale is a thick one4    ,figs4  
#b and #c show this effect exaggerated4 
,b is the block against which  the scale
 abuts4 ,the dotted line indicates where
 the caliper leg should  rest1 but      
cannot do so1 unless the scale is held  
perfectly square with the  block4 ,fig4 
#d shows a method of setting the        
calipers by using a small  square to    
abut the scale and to afford a surface  
against which to place the  leg of the  
caliper4 ,the scale1 lying flat on the  
blade of the square1 is  always sure to 
be square edgewise1 and is easily held  
squarely against the  stock of the      
square as shown4 ,this method has also  
the advantage of being  portable1 and   
can be taken to the window or to any    
place where the light is  satisfactory4 
,when using a long scale1 the free end  

may be held against the  body to assist 
in holding it in place4#b    ,shoulder  
,calipers    ,illustration3 ,fig4 #e4   
,shoulder ,calipers    ,in ,fig4 #e are 
shown a pair of calipers which are very 
handy in measuring  work from shoulder  
to shoulder or from a shoulder to the   
end of the piece  of work4 ,for this    
purpose they are much handier1 and more 
accurate1 than  the ordinary            
hermaphrodites4 ,the legs are bent at   
,,aa so as to lie flat  and thus bring  
the point of the long leg directly      
behind the short one  which nests into  
it1 as at ,b1 so that the calipers may  
be used for  short measurements as well 
as for long ones4    ,double-jointed    
,calipers to ,fold in ,tool ,box    ,in 
,fig4 #f are illustrated a pair of large
 calipers that can be folded up  and put
 in a machinist's ordinary size tool    
chest4 ,the usual large caliper         
supplied by the average machine shop is 
so cumbersome and heavy that this  one  
was designed to fill its place4 ,it can 

be carried in the chest when the  usual 
style of large caliper cannot4 ,it is a 
very light and compact tool4  ,it is a  
#bf-;inch caliper1 and will caliper up  
to #cd inches diameter4 ,the top        
sections are made in four pieces1 and   
the point ends fit between the top  half
 like the blade of a knife1 as shown in 
the engraving4 ,each side of the  upper 
or top section is made of saw steel     
#a_/af inch thick1 and the lower  part  
or point of steel #a_/h inch thick4 ,the
 double section makes the tool  very    
stiff and light4    ,the point section  
has a tongue ,a1 extending between the  
double section1  which is engaged by a  
sliding stud and thumb nut4 ,the stud is
 a nice  sliding fit in the slot1 and   
the thumb nut clamps it firmly in place 
when  in use4 ,b1 in the figure1 shows  
the construction of the thumb nut4 ,c is
  a sheet copper liner put between the  
washers at ,a4 ,the dotted lines in  the
 engraving show the points folded back  
to close up4 ,the large joint  washers  

are #a inch diameter1 and a #e_/h-;inch 
pin with a #c_/h-;inch hexagon  head    
screw tightens it up4 ,the forward      
joints are the same style1 but  smaller4
 ,the main joint has two #a-;inch brass 
distance pieces or washers  between the 
two main washers4 ,the top section is   
#ab inches between  centers1 and the    
point sections #ae inches from center to
 point4 ,closed up1  the calipers       
measure #af inches over-all4            
,illustration3 ,fig4 #f4 ,large         
,double-jointed ,calipers    ,kinks in  
,inside ,calipering    ,close           
measurements may be made by filing two  
notches in each leg of an  inside       
caliper so as to leave a rounded        
projection between1 as shown at  ,e1    
,fig4 #g4 ,then1 with an outside        
caliper1 ,d1 the setting of the inside  
caliper1 ,b1 is taken from the rounded  
points4 ,the inside caliper can be      
reset very accurately after removal by  
this method4 ,a still better way is  to 
have two short pins1 ,,cc' set in the   

sides of the inside caliper legs1  but  
this is not readily done as a makeshift4
 ,to measure the inside diameter  of a  
bore having a shoulder like the piece   
,h1 the inside caliper ,f may  also be  
set as usual and then a line marked with
 a sharp scriber on one  leg1 by drawing
 it along the side ,g4 ,then the legs   
are closed to remove  the caliper1 and  
are reset to the scribed line4 ,of      
course1 this method is  not as accurate 
as the previous one1 and can be used    
only for approximate  measurements4     
,illustration3 ,fig4 #g4 ,methods of    
,inside ,calipering    ,to get the      
thickness of a wall beyond a shoulder1  
as at ,k1 ,fig4 #g1 set  the caliper so 
that the legs will pass over the        
shoulder freely1 and with a  scale      
measure the distance between the outside
 leg and the outside of the  piece4     
,then remove the caliper and measure the
 distance between the caliper  points4  
,the difference between these two       
distances will be the thickness  ,m4    

,inside ,calipers for ,close ,spaces    
,in ,fig4 #h are shown a pair of inside 
calipers which are bent so as to be     
well adapted for calipering distances   
difficult of access1 such as the  keyway
 in a shaft and hub which does not      
extend beyond the hub1 as  indicated4   
,with the ordinary inside calipers1     
having straight legs1 and  which are    
commonly used for inside work1 it is    
generally impossible to get  the exact  
size1 as the end which is held in the   
hand comes in contact with  the shaft   
before both points come into the same   
vertical plane4 ,the  engraving plainly 
shows how calipers for this purpose are 
made1 and how  used4 ,any mechanic can  
easily bend a common pair to about the  
shape shown  to accommodate this class  
of work4#c    ,illustration3 ,fig4 #h4  
,inside ,calipers for ,close ,spaces    
,surface ,gage with ,two ,pointers      
,figs4 #i and #aj show a special surface
 gage1 and illustrate an original idea  
which has been found to be a great saver

 of time and of milling cutters4 ,it    
can also be used on the planer or       
shaper4 ,by its use the operator can    
raise  the milling machine table to the 
right height without testing the cut two
  or three times1 and eliminate the     
danger of taking a cut that is liable to
  break the cutter4 ,this tool is       
especially valuable on castings1 as     
raising  the table and allowing the     
cutter to revolve in the gritty surface 
while  finding the lowest spot is very  
disastrous to the cutting edges4        
,illustration3 #aj    ,to use this      
surface gage1 the pointer marked ,c in  
,fig4 #i is set to the  lowest spot in  
the casting1 and then the pointer ,b is 
set from it with  perhaps #a_/cb inch   
between the points for a cut sufficient 
to clean up the  surface4 ,pointer ,c is
 then folded up as shown at ,c' in ,fig4
 #aj1 and the  table is raised until the
 pointer ,b will just touch the under   
side of the  cutter as shown at ,b' in  
,fig4 #aj4 ,in this way the table is    

quickly  adjusted to a cut that will    
clean the casting or other piece being  
machined1 and with no cutting or trying 
whatever4#d    ,to ,adjust the ,needle  
of a ,surface ,gage    ,illustration3   
,fig4 #aa4 ,method of ,adjusting the    
,needle of a ,surface ,gage             
,illustration3 ,fig4 #ab4 ,scale        
,attachment for the ,square    ,fig4 #aa
 illustrates a method of adjusting the  
needle of a surface gage4 ,to  set the  
gage #c inches from the table1 get      
somewhere within  inch of the  mark on  
the square4 ,with the thumb and         
forefinger on hook ,a1 turn the  needle 
till it reaches the point desired4 ,by  
turning the needle1 it will  travel in a
 circular path1 on account of the bend  
near the point1 and thus  reach the     
desired setting4    ,scale ,attachment  
for the ,square    ,fig4 #ab shows a    
device for attaching a scale to a       
square4 ,this combination  makes a very 
convenient tool to use when setting up  
work for keyseating1 as  is illustrated 

in the engraving1 in which ,s is the    
shaft to be splined  and ,c the milling 
cutter4 ,it is also a very handy tool   
for truing up work  on the boring mill  
or lathe4 ,at the upper left-hand       
corner1 is shown the  construction of   
the parts1 which are made of dimensions 
to suit the size of  the scale and the  
square4 ,for the combination to be      
successful1 it is  essential that the   
blade of the square is the same         
thickness as the  scale4#e              
,attachment for ,machinist's ,scale     
,illustration3 ,fig4 #ac4 ,convenient   
,attachment for ,machinist's ,scale     
,fig4 #ac shows a very convenient       
appliance4 ,it will be found very useful
 in  the machine shop for setting inside
 calipers to any desired size4 ,the gage
  is clamped over the rule wherever     
desired1 and one leg of the calipers set
  against the gage1 the other leg being 
brought flush with the end of the       
scale4#f    ,setting ,dividers          
,accurately    ,to set dividers         

accurately1 take a #a-;inch micrometer  
and cut a line  entirely around the     
thimble as at ,a1 ,fig4 #ad1 and then1  
with the  instrument set at zero1 make a
 punch mark ,b exactly one inch from the
  line on the thimble4 ,if less than one
 inch is wanted1 open out the           
micrometer and set the dividers to the  
dot and line so as to give one inch     
more than the distance wanted4 ,now with
 the dividers make two marks across  a  
line1 as at a and b1 ,fig4 #ad1 and then
 set the dividers to one inch  and mark 
another line as at c4 ,the distance from
 c to b is the amount  desired1 and the 
dividers can be set to it4 ,great care  
must1 of course1 be  exercised1 if      
accurate results are required4          
,illustration3 ,fig4 #ad4 ,method of    
,setting ,dividers ,accurately          
,combination ,caliper and ,divider      
,the combination caliper and divider    
shown in ,fig4 #ae is one that is not   
manufactured by any of the various tool 
companies4 ,it is1 however1 one of  the 

handiest tools that can be in a         
machinist's kit1 as it lends itself to  
so many varied uses1 and often is       
capable of being used where only a      
special tool can be employed4 ,the      
illustration suggests its usefulness4   
,the  tool can be used as an outside    
caliper1 as an inside caliper1 and as a 
divider4 ,the common form of this tool  
has generally only one toe on the       
caliper legs1 but the double toes save  
the reversal of the points when         
changing from outside to inside work4   
,the divider points may be set at an    
angle1 which permits of stepping off    
readily around the outside of a shaft   
at angular distances1 where the ordinary
 dividers are useless4 ,a number of     
other uses could be mentioned1 but any  
intelligent mechanic can readily        
suggest them for himself4               
,illustration3 ,fig4 #ae4 ,combination  
,caliper and ,divider    ,attachment for
 ,vernier ,calipers    ,while vernier   
and slide calipers are very handy shop  

tools1 their  usefulness is much more   
limited than it ought to be for such    
expensive  instruments4 ,in order to    
increase the usefulness of these tools1 
the  attachments shown in ,fig4 #af may 
be made4 ,in the upper left-hand part of
  the engraving the details of a useful 
addition to the caliper are shown4  ,a  
is made of machine steel1 while the     
tongue ,b is of tool steel1  hardened   
and ground and lapped to a thickness of 
#j4aej inch1 the top and  bottom being  
absolutely parallel4 ,this tongue is    
secured to ,a by the two  rivets ,,cc4  
,the thumb-screw ,d is used for         
fastening the attachment to  the sliding
 jaw of the vernier or slide caliper4   
,in the upper part of the  engraving is 
shown the base1 which is of machine     
steel1 with the slot ,f  milled for the 
reception of the fixed jaw of the       
caliper4 ,the set-screws  ,,ggg are put 
in at a slight angle so that the caliper
 will be held firmly  and squarely in   
this base4 ,in the figure to the left   

these pieces are shown  in the position 
for forming a height gage1 for which    
purpose the attachment  is most commonly
 used4 ,as a test of the accuracy of its
 construction when  the attachment is   
placed in this position1 the tongue ,b  
should make a  perfect joint with the   
fixed jaw of the caliper1 and the       
vernier should  give a reading of       
exactly #j4aej4 ,when it is desirable   
that the tongue ,b  should overhang1 the
 base ,e is pushed back even with the   
stationary jaw1  as shown in the        
engraving to the right4 ,in this        
position it is used for  laying out and 
testing bushings in jigs1 etc4 ,the     
illustration shows the  tool in use for 
this purpose1 ,k being the jig to be    
tested4 ,all  measurements are from the 
center line upon which the bushing ,no4 
#a is  placed4 ,taking this as a        
starting point we find the caliper to   
read #a inch4  ,bushing ,no4 #b1 which  
is undergoing the test1 should be #e_/h 
inch from this  center line4 ,it has a  

-inch hole1 and we therefore insert a   
plug of this  diameter4 ,now adjust the 
tongue of the caliper to the bottom of  
this plug  7as shown in the engraving7  
and the vernier should read #a4fbe minus
  one-half the diameter of the plug1 or 
#a4ejj1 and any variation from this     
will show the error of the jig4 ,in this
 case the top surface of ,b was  used   
and no allowance had to be made for its 
thickness4 ,in case the bottom  surface 
is used1 #j4aej must be deducted from   
the reading of the caliper4             
,illustration3 ,fig4 #af4 ,attachment   
for ,vernier ,calipers    ,it is very   
easy to make a mistake in setting a     
bushing1 and such a mistake  is equally 
hard to detect unless some such means of
 measuring as this is at  hand4 ,it     
often happens that jigs and fixtures are
 put into use containing  such errors1  
and the trouble is not discovered until 
many dollars' worth of  work has been   
finished and found worthless4 ,the      
illustration shows but one  of the many 

uses to which this attachment may be    
applied4 ,the figures given  on the     
details are correct for making an       
attachment to be used upon the  ,brown  
,sharpe vernier caliper1 but for other  
calipers they would1 of  course1 have to
 be altered to suit4#g    ,improved     
,micrometer ,beam ,caliper              
,illustration3 ,fig4 #ag4 ,improved     
,micrometer ,beam ,caliper    ,in a beam
 caliper having a sliding micrometer jaw
 with or without a  separate clamping   
slide1 it is necessary to have the beam 
divided into unit  spaces1 at which the 
jaw or slide may be accurately fixed1   
the micrometer  screw then being used to
 cover the distance between the         
divisions2 but it  is difficult to      
construct a beam caliper of this type   
with holes for a  taper setting pin1 at 
exactly equal distances apart2          
consequently a plan  that is generally  
followed in making such tools is to     
provide as many holes  through the slide
 and beam as there are inch divisions1  

each hole being  drilled and reamed     
through both the slide and beam at once4
 ,if it were  attempted to drill the    
holes through the beam at exactly one   
inch apart1  having only one hole in the
 clamping head and using it as a jig for
 the  purpose1 it would be found very   
difficult1 if not impossible1 to get the
  holes all of one size and exactly one 
inch apart4 ,the design of the          
micrometer beam caliper shown in ,fig4  
#ag1 which has been patented by ,mr4    
,frank ,spalding1 ,providence1 ,rhode   
,island1 is such1 however1 that it is   
not  necessary to drill more than one   
hole through the clamping slide4 ,the   
beam  ,f is grooved longitudinally1 and 
in the groove are fitted hardened steel 
adjusting blocks in which a taper hole  
,d is accurately finished4 ,between  the
 blocks are filling pieces ,g1 which are
 brazed or otherwise fastened  in the   
groove4 ,holes are drilled1 tapped1 and 
countersunk between the  blocks and the 
filling pieces ,g1 in which are fitted  

taper head screws  ,,ee#a4 ,the         
construction is thus obviously such that
 the blocks may be  shifted             
longitudinally by loosening one screw   
and tightening the other4 ,in           
constructing the caliper1 the holes     
through the beam are drilled as         
accurately as possible1 one inch apart1 
and centered in the longitudinal        
groove1 but are made larger than the    
holes in the blocks1 so as to provide   
for slight adjustment4    ,large ,beam  
,caliper    ,illustration3 ,fig4 #ah4   
,large ,beam ,caliper    ,fig4 #ah shows
 a large beam caliper designed for      
machinists and  patternmakers4 ,it      
consists of a beam ,,mn and the legs ,r 
and ,s1 made of  cherry wood to the     
dimensions indicated4 ,the legs are     
secured in position  on the beam by     
means of the thumb screws ,a1 which jam 
against the gibs  ,c at the points of   
the screws4 ,the gibs have holes        
countersunk for the  screws to enter1 to
 hold them approximately in place1 and  

the nuts ,b are  of brass1 fitted into  
the filling pieces ,p that keep them    
from turning4  ,the filling pieces are  
riveted to the legs by means of cherry  
dowels ,d4  ,one leg ,s is provided with
 a fine adjustment consisting of        
flexible steel  spring ,h1 ending in a  
point which is adjusted by the thumb    
screw ,e4  ,this screw is locked in     
adjustment by the check nut ,g bearing  
against the  brass nut ,f1 which is     
inserted in the leg as shown4#h         
99       99       99       99       99  
,,chapter ,,iii    ,,micrometer         
,,measuring ,,instruments    ,of all    
measuring instruments used in the shop  
intended for accurate  measurements1    
those working on the principle of the   
ordinary micrometer  calipers are the   
most common4 ,in the present chapter we 
shall describe and  illustrate a number 
of different designs of these tools1    
intended to be  used for various        
purposes4 ,the instruments shown in     
,figs4 #ai to #bc were  built1 in       

leisure hours1 by ,mr4 ,a4 ,l4 ,monrad1 
of ,east ,hartford1 ,conn4              
,micrometer for ,snap ,gages            
,illustration3 ,fig4 #ai4 ,micrometer   
for ,snap ,gages    ,fig4 #ai shows a   
form of micrometer that has proved very 
handy for measuring  snap gages1 and    
thicknesses1 and can also be used as a  
small height gage to  measure the       
distance from a shoulder to the base1 as
 shown in ,fig4 #bj4 ,in  measuring snap
 gages or thicknesses1 the outside and  
inside of the  measuring disks are used1
 respectively4 ,this instrument may also
 come in  very handy when setting tools 
on the planer or shaper4 ,as will be    
seen in  the engraving1 there are two   
sets of graduations on the sleeve ,a1   
thus  enabling the operator to tell at a
 glance what measurement is obtained    
from  the outside or the inside of the  
measuring disks4 ,each of the disks is  
#j4ajj inch thick1 so that the range of 
the micrometer is #j4hjj and #a4jjj     
inch for the outside and inside1        

respectively4 ,the details of the       
instrument are as follows3    ,the      
sleeve ,a is composed of the inside     
measuring disk1 the graduated  sleeve1  
and the micrometer nut combined4 ,on the
 disk are two projections  ,,kk1 which  
are knurled1 thus providing a grip when 
operating the tool4 ,the  sleeve is     
threaded on the inside of one end1 which
 acts as a micrometer  nut1 and the     
outside of this same end is threaded to 
receive the adjusting  nut ,d4 ,the     
sleeve has two slots1 each placed #ij   
degrees from the  graduations1 and these
 provide for compensation for wear4 ,the
 disk part is  hardened by heating in a 
lead bath1 and is finished by grinding  
and  lapping4 ,the barrel ,b is the same
 as a regular micrometer barrel1 and is 
graduated with #be divisions4 ,spindle  
,e consists of the outside disk and  the
 micrometer screw1 and the barrel ,b    
fits on its end1 which is tapped  out to
 receive the speeder ,c1 which serves to
 hold the barrel in  position4 ,the     

thread is  inch1 #dj pitch1 and the disk
 and unthreaded parts  are hardened1    
ground and lapped4 ,to adjust this1     
instrument1 loosen the  speeder ,c and  
turn the barrel until the proper        
adjustment is obtained4  ,then lock the 
barrel by tightening the speeder        
again4#i    ,illustration3 ,fig4 #bj4   
,micrometer in ,fig4 #ai used as ,height
 ,gage    ,micrometer ,caliper ,square  
,fig4 #ba shows an assembled view and   
the details of a micrometer caliper     
square which1 if accurately made1 is    
equal and often preferable to the       
vernier caliper now so generally used4  
,one of its advantages over the  vernier
 is that when the measurement is taken1 
it can be readily discerned  without    
straining the eyes1 and this instrument 
is as easy to manipulate as  the regular
 micrometer4    ,in the details1 part   
,a1 which is the main body of the       
instrument1 is made  of tool steel1 the 
forward or jaw end being solid with the 
body4 ,this end  is hardened1 and the   

jaw ground and lapped4 ,the body is     
bored out and two  flats milled on the  
outside1 which lighten it up and make it
 neat in  appearance4 ,the jaw end is   
counterbored out with a #de-;degree     
counterbore to  form a bearing for the  
forward end of the micrometer screw4 ,a 
slot1 #a_/h  inch in width1 extends from
 the fixed jaw to the other end1 and in 
this  slides the movable jaw ,c4 ,there 
are #dd divisions along the side of this
  slot1 each division being #j4jej inch 
apart1 giving the tool a range of       
#b4jjj inches for outside and #b4bjj    
inches for inside measurements4 ,the    
screw ,b is the most essential part of  
this tool1 its construction  requiring  
great accuracy4 ,its diameter is #c_/h  
inch and it is cut with #bj  threads per
 inch4 ,on its forward end fits the cone
 ,f1 which is hardened  and ground1 the 
round part acting as the forward bearing
 of the screw and  fitting in the       
#de-;degree counterbored hole in the    
body ,a4 ,on its other  end fits the    

graduated barrel ,d and also the speeder
 ,g4    ,illustration3 ,fig4 #ba4       
,micrometer ,caliper ,square    ,the    
barrel is graduated in fifty divisions1 
each division equaling #j4jja  inch4 ,on
 the inside of the barrel is a          
#de-;degree bearing which rides on the  
cone ,m1 the cone being held stationary 
on the end of the body4 ,thus it  will  
be seen that both front and back ends of
 the micrometer screw are  carried in   
cone bearings1 which give a very small  
point of contact1 thereby  causing but  
little friction and preventing any      
danger of gumming up so as  to run hard4
 ,the sliding jaw ,c is made of tool    
steel1 hardened1 ground  and lapped1 and
 combined with it is the micrometer nut 
which is drawn to a  spring temper4     
,this nut is split and adjusted by two  
screws to compensate  for wear4 ,on this
 jaw are the two zero marks that tell at
 a glance the  outside or inside        
measurements taken4 ,the screw and      
washer1 marked ,h and  ,i1 go onto the  

end of the micrometer screw and take up 
the end play4 ,to  make a neat          
appearance1 the cap ,e is placed in the 
forward counterbored  hole1 being held  
in place by a tight fit4 ,the adjustment
 of the tool is  accomplished by        
loosening the speeder ,g and turning the
 barrel on the  screw2 when the         
adjustment is made1 the speeder is again
 tightened down and  the barrel         
locked4#aj    ,micrometer ,depth ,gage  
,the depth gage1 shown in ,fig4 #bb1 has
 a -inch movement of the rod1 and may   
be used with rods of any desired length4
 ,these have small                      
#de-;degree-on-a-side grooves cut into  
them at intervals of  inch4 ,a small    
spiral spring1 marked ,i1 gives the rod 
a constant downward pressure1 so  that1 
when taking a measurement1 the base of  
the tool is placed on the  piece of     
work1 and the rod always finds the      
bottom of the hole2 then1 by  tightening
 the knurled screw ,f the rod is clamped
 in position and the  tool may be picked

 up and its measurement read from the   
dial4 ,the  graduations on this         
instrument are similar to those of the  
vernier caliper1  only they are much    
plainer1 as a half-inch movement of the 
rod turns the  dial one complete        
revolution4 ,the figures on the dial    
denote tenths of an  inch1 and those on 
the body of the tool thousandths2 each  
graduation on the  dial is therefore    
equal to #j4jaj1 so that to show the    
depth of a hole to be  #j4cgc the dial  
would be revolved around so that the    
seventh division beyond  the #c mark    
would be near to #j1 and then by looking
 from the #j mark toward  the left1 the 
third graduation on the body and one on 
the dial would be in  line1 thus        
denoting #j4cgc4    ,illustration3 ,fig4
 #bb4 ,micrometer ,depth ,gage    ,the  
most essential part of this tool is the 
threaded screw ,b1 which acts  as a     
rack1 and the worm-wheel1 solid with the
 dial ,c4 ,the upper end of  the screw  
forms a split chuck which grips the     

measuring rods1 while the  part marked  
,r is flatted off1 and against this     
portion bears a threaded  sleeve ,g1    
which acts as a key to keep the screw in
 position4 ,this sleeve  is threaded1   
both inside and outside1 and screws into
 the body of the tool1  while the       
binding screw ,f fits into it and binds 
against a small piece of  copper1 marked
 ,h1 which in turn holds the screw in   
position4 ,the thread  on ,b is #j4bde  
inch in diameter and is cut with #dj    
threads per inch4 ,the  worm-wheel which
 meshes into this screw is solid with   
the dial1 as shown at  ,c4 ,it is #j4ah 
inch in diameter1 and requires great    
accuracy in cutting2  it is not hobbed1 
but the teeth1 of which there are       
twenty1 are milled with  a circular     
cutter of the same diameter as the screw
 ,b plus #j4jjb inch4  ,the little      
studs1 marked ,,ee1 on the dial and on  
the body ,k1 hold the  coiled spring in 
position4 ,very great accuracy must be  
attained when  locating the holes in ,k 

that are to receive the screw and dial  
,b and  ,c4 ,the screw marked ,j fits   
into the dial1 where it serves as a     
bearing  and also holds the dial in     
position4 ,the knurled cap ,d tightens  
the split  chuck in order to hold the   
measuring rod firmly4#aa    ,indicator  
for ,accuracy of ,lead-screws           
,illustration3 ,fig4 #bc4 ,indicator for
 ,accuracy of ,lead-screws    ,all of   
the tools that have been described      
require an accurately cut screw1  and1  
as very few lathes are capable of       
producing this1 it may be well to       
illustrate an indicator for testing the 
accuracy of the lead-screw1 and to      
explain the method by which it is used4 
,this instrument is shown in ,fig4  #bc1
 where it is applied to a test screw ,k4
 ,it consists of a body ,a on  one end  
of which is a projection ,l serving as  
the upper bearing for the  pivoted lever
 ,d4 ,this lever swings about a small   
steel pivot which can be  adjusted by   
the screw ,e4 ,the rear end of the lever

 is forked1 and between  the prongs is  
passed a thread making a double turn    
about the pivot ,f that  carries the    
pointer ,j4 ,any movement of this lever 
will1 therefore1 cause  this pointer to 
revolve about the dial ,c4 ,this dial   
has #bj divisions1  each indicating     
one-half thousandth of an inch movement 
of the front end of  the lever1 so that 
a total revolution of the pointer about 
the dial would  indicate a movement of  
the front end of the lever of #j4jbj    
inch4 ,the screws  ,i serve to hold the 
dial in place on the body of the        
indicator1 while the  spring ,m keeps   
the pointer normally at the zero mark4  
,the indicator is  held in the toolpost 
by the arm ,g1 which can be set at any  
angle and  firmly clamped by the screw  
,h4    ,to use the indicator1 remove the
 screw from a micrometer which is known 
to  be accurate1 and1 with the aid of a 
brass bushing1 chuck it in the lathe so 
that the thread end will project4 ,now  
gear the lathe to cut #dj threads per   

inch and apply the indicator4 ,when the 
lathe is started1 the point of the      
indicator follows along in the thread of
 the micrometer screw1 and any          
variation in the lead will be noted by a
 movement of the pointer over the  dial4
 ,if1 on the other hand1 no movement    
takes place1 it is an indication  that  
the pitch of the lead-screw is          
correct4#ab    ,micrometer ,attachment  
for ,reading ,ten-thousandths of an     
,inch    ,illustration3 ,fig4 #bd4      
,micrometer with ,attachment for        
,reading  ,ten-thousandths of an ,inch  
,fig4 #bd shows an attachment for       
micrometers designed and made for       
readings  in tenths of thousandths of an
 inch4 ,with very little fitting it is  
interchangeable for #a-1 #b-1 or        
#c-;inch ,b4  ,s4 micrometers4 ,the idea
 is  simple1 as can be seen by the      
illustration4 ,the diameter of the      
thimble is  increased #c to #a by a disk
 which is graduated with #bej lines     
instead of #be1  making each line       

represent #j4jjja inch instead of #j4jja
 inch4 ,a piece of  steel is then turned
 up and bored and cut away so as to form
 the index  blade and a shell to clasp  
the micrometer frame1 the whole thing   
being made  in one piece4 ,the thimble  
disk being just a good wringing fit1 it 
can be  easily adjusted #j to #j4 ,the  
attachment can be removed when fine     
measuring  is not required4#ac          
,special ,micrometer for ,large         
,dimensions    ,fig4 #be shows a        
#f-;inch micrometer caliper designed for
 measuring from #j to  #f inches by     
half-thousandths4 ,the sliding          
micrometer head travels on a  cylinder  
barrel through which a hole is          
accurately bored to suit three  plugs1  
one1 two1 and three inches long1 as     
shown in the engraving4 ,these  plugs   
serve to locate the traveling head at   
fixed distances one inch apart4  ,the   
micrometer screw itself has a travel of 
one inch1 like any standard  micrometer4
 ,a locknut is used to hold the screw in

 any desired position4 ,a  thumb screw  
at the end of the barrel bears against  
the end plug1 and zero  marks are       
provided to bring the screw against the 
plug with the same degree  of pressure  
at each setting4 ,when the head is      
clamped by means of the  locking nut1 it
 is as rigid as though it were solid    
with the barrel1 and  the faces of the  
measuring points are thus always        
parallel4    ,illustration3 ,fig4 #be4  
,special ,micrometer for ,large         
,dimensions    ,combination ,micrometer 
,illustration3 ,fig4 #bf4 ,combined     
,one- and ,two-inch ,micrometer    ,a   
combined one- and two-inch micrometer is
 shown in ,fig4 #bf4 ,one side  records 
measurements up to one inch1 and the    
other side up to two inches4 ,a  single 
knurled sleeve or nut serves to move the
 double-ended measuring  piece one way  
or the other as desired1 this piece     
having a travel of one  inch4 ,the      
spindle is non-rotating1 so that the    
faces of the screw and anvil  are always

 parallel4 ,a locking device holds the  
screw in any position4 ,this  tool is   
convenient for use both in measuring and
 as a gage1 since it can be             
conveniently held by the finger ring    
appearing at the back4    ,micrometer   
,stop for the ,lathe    ,most micrometer
 lathe stops are limited in their use to
 work where only a  stationary height is
 required4 ,it is1 however1 often       
necessary to use the  stop at different 
heights1 to accommodate different       
lathes2 then again1 we  wish to use it  
on the right-hand side as well as the   
left4 ,the form of  holder shown in     
,fig4 #bg can be used either right or   
left1 and for various  heights1 and1 by 
simply taking out the screw ,a1 the     
micrometer may be  removed and used in  
any other form of holder desired4       
,illustration3 ,fig4 #bg4 ,micrometer   
,stop for the ,lathe    ,both an        
assembled view and details of the holder
 are shown in the  engraving1 so that it
 can be easily constructed by any one   

desiring to do  so4 ,the micrometer and 
barrel may be procured from any of the  
manufacturers  of measuring instruments4
 ,the swivel ,c is bored out so that the
 axis of  the micrometer screw will be  
parallel to the body of the holder when 
it is  in place4 ,the swivel is made of 
tool steel and is fastened to the holder
 by  the screw ,a4 ,it is hardened and  
lapped to a true bearing surface on the 
sides and bottom1 and so adjusted that  
it will turn to either side and  remain 
in the desired position without moving  
the screw4 ,the holder ,b is  milled    
through its entire length with a        
#ij-;degree cutter so that it will  fit 
along the ways of the lathe1 and the    
bottom is lapped to a true  surface4    
,for a neat appearance1 the tool should 
be color hardened4 ,on top  the holder  
is spotted or countersunk with a drill  
to form a recess for the  ,c-clamp4 ,a  
knurled ring ,d is driven onto the      
micrometer sleeve so that it  can be    
turned around to bring the graduations  

uppermost when the position  of the     
barrel is changed4#ad    ,micrometer    
,surface and ,height ,gage              
,illustration3 ,fig4 #bh4 ,micrometer   
,surface and ,height ,gage    ,fig4 #bh 
shows a form of surface gage that has   
proved very handy1 and which  can be    
used also as a height gage for measuring
 distances from shoulders to  the base4 
,if accurately made it is equal1 and    
often preferable1 to the  vernier or    
slide caliper now so generally used with
 an attachment to the  sliding jaw4 ,one
 of its advantages over the vernier is  
the readiness with  which the           
graduations are discerned1 and it is as 
easy to manipulate as the  ordinary     
micrometer4 ,the part ,b1 which forms   
the main body of the  instrument1 is    
made of tool steel1 and one end is      
fitted into the base  where it is held  
in position by the screw ,d4 ,the       
remainder is milled to a  thickness of  
#a_/h inch and has graduations of #j4jbe
 inch for a distance of  three inches4  

,the screw ,a is the most essential part
 of the tool1 and its  construction     
requires great accuracy4 ,its diameter  
is  inch1 and it is cut  with #bj       
threads per inch4 ,in the upper end of  
the screw is driven the ball  ,h for the
 sake of giving a neat appearance4 ,the 
top of the thread is  turned off #j4jaj 
inch to allow the scriber ,f to slide   
freely on the  screw4 ,the barrel ,i is 
used for raising and lowering the slide1
 but  instead of having the graduations 
placed directly upon it1 they are made  
upon the sleeve ,c1 which fits over a   
shoulder on the barrel4 ,this allows    
more easy means of adjustment than would
 be possible were the graduations       
placed on the barrel itself4 ,the sleeve
 is graduated with fifty divisions  each
 equaling a movement of the scriber of  
#j4jja inch4 ,this sleeve may be  turned
 by means of a small spanner wrench so  
as to bring the zero line into  correct 
position to compensate for wear4 ,a     
knurled locking nut is also  provided   

for holding the scriber in any fixed    
position4 ,the scriber itself  is       
hardened and lapped to a finished       
surface1 the tail end being slotted  and
 provided with two screws to compensate 
for wear4 ,on the scriber is  placed the
 zero mark which shows at a glance the  
measurement that is being  taken4 ,the  
block ,k is three inches in height1 and 
by using this block and  placing the    
gage on its top1 the range of the gage  
is increased to six  inches4 ,the screw 
,e is used for fastening the gage to the
 top of the  block4 ,the center of the  
block is drilled out and slots cut      
through the  sides in order to make it  
light and neat in appearance4#ae        
,micrometer of from ,one- to ,five-inch 
,capacity    ,illustration3 ,fig4 #bi4  
,micrometer of from ,one- to ,five-inch 
,capacity    ,fig4 #bi shows a very     
simple and light five-inch micrometer   
that can be  quickly set to exact       
position from one to five inches4 ,the  
round beam is  graduated by a series of 

angular grooves1 #a inch apart1 which   
are of such a  form and depth that the  
clamping fingers at the end of part ,a  
spring in1  allowing one inch adjustment
 of the beam to be quickly and          
positively made4  ,the sleeve ,k is of  
tool steel1 being counterbored from the 
forward end  for all but one-half inch  
of its length4 ,for this half inch it is
 threaded  on the inside and acts as a  
micrometer nut4 ,the outside of the same
 end is  threaded to receive the        
adjusting nut ,f1 and two slots are cut 
in the  sleeve1 at #ij degrees with the 
graduations4 ,these slots1 by a movement
 of  the nut ,f1 provide a means for    
compensating for wear4 ,the bushing ,e  
is  hardened and lapped1 and fitted     
tightly in the forward counterbore of   
this  sleeve1 where it acts as a guide  
for the front end of the micrometer     
screw4  ,the barrel ,j is the same as   
that of a regular micrometer1 and is    
graduated in #j4jbe inch divisions4     
,the most essential part of the tool is 

the threaded screw ,i1 over the end  of 
which fits the barrel ,j4 ,the end is   
tapped out to receive the speeder  ,h1  
which serves to hold the barrel in      
position4 ,the thread is #e_/af inch  in
 diameter1 with #dj threads per inch1   
while the unthreaded part is  hardened1 
ground and lapped4 ,to adjust the       
instrument1 loosen the speeder  ,h and  
turn the barrel until the proper        
adjustment is obtained2 lock the  barrel
 by again tightening the speeder4 ,the  
beam ,c has a -inch hole  drilled       
throughout its entire length in order to
 make it light4 ,small  #ij-;degree     
grooves are cut into it at intervals of 
#a inch1 and a #a_/h-;inch  slot is     
milled through one side to within #a    
inch of the forward end4 ,the  back end 
of part ,a forms a spring-tempered split
 chuck1 which grips the  beam and holds 
,a in position1 while the exterior is   
threaded to receive  the knurled cap ,b 
by which the chuck is tightened firmly  
to the beam4  ,from the front end1      

toward the split chuck1 the body is     
counterbored #e_/h  inch and the bushing
 ,d driven in tight4 ,this bushing has a
 key ,g fitted  into it1 which slides in
 the slot of the beam and prevents the  
arm from  turning4 ,the projecting arm  
is bored and tapped to receive the      
sleeve ,k4  ,this gage must be carefully
 and accurately made to be of value4#af 
,inside ,micrometer for ,setting        
,calipers    ,illustration3 ,fig4 #cj4  
,method of ,setting ,calipers from      
,inside ,micrometers    ,fig4 #cj shows 
an application of inside micrometers    
which is very handy4 ,the  hole for the 
scriber in the scriber clamp of a       
surface gage is reamed out  to fit the  
rods used with inside micrometers4 ,this
 forms a convenient  holder for the     
micrometer when used for setting outside
 calipers to it4 ,the  calipers can be  
set easily and accurately at the same   
time1 and where  extreme accuracy is not
 necessary this arrangement is more     
handy than that  of using large-sized   

micrometers4    ,with care and practice 
an accuracy of within one-quarter of    
#j4jja inch is  obtainable in this way4 
,mistakes1 in fact1 are more easily     
guarded against  than is the case when  
using the micrometers directly4         
,micrometer ,frame    ,illustration3    
,fig4 #ca4 ,useful and ,handy           
,micrometer ,frame    ,fig4 #ca shows a 
micrometer frame used some years ago at 
the ,westinghouse  works4 ,the frame is 
an aluminum casting1 and the anvil is   
simply a  tool-steel pin1 which fits    
well in the hole into which it is       
inserted1 and  can be clamped anywhere  
within the limits of its length4 ,the   
micrometer end  of the frame is supplied
 with an inside micrometer head4 ,the   
tool is  adjusted to a gage1 either to a
 standard pin gage1 or to an inside     
micrometer gage4 ,the capacities of     
three of these micrometers in a set may 
be from about #c to #g inches1 #f to #aa
 inches1 and #aj to #ae inches4 ,when   
the  head is turned outward1 as shown in

 the lower view in the cut1 the tool is 
very handy around a horizontal boring   
machine where a pin gage cannot be  used
 without removing the boring bar4       
,micrometer ,stop for the ,lathe        
,illustration3 ,fig4 #cb4 ,micrometer   
,stop for the ,lathe    ,the simple     
micrometer stop shown in ,fig4 #cb is   
used on the engine lathe for  obtaining 
accurate movements of the lathe         
carriage4 ,it consists of a  micrometer 
head1 which can be purchased from any   
micrometer manufacturer1  and a machine 
steel body which is bored to fit the    
micrometer head4 ,this  tool is clamped 
on the front way of the lathe bed1 and  
when the jaw of the  micrometer is      
against the lathe carriage1 it can      
easily be adjusted to a  thousandth of  
an inch4 ,of course1 care should be     
taken not to bump the  carriage against 
the micrometer4#ag    ,use of           
,micrometer for ,internal ,thread       
,cutting    ,illustration3 ,fig4 #cc4   
,method of using ,micrometer for        

,internal ,thread  ,cutting    ,fig4 #cc
 illustrates a means of determining the 
size of internally threaded  work4 ,the 
work shown is intended for a lathe      
chuck4 ,the outside diameter of  the hub
 on the work is turned to the same size 
as the hubs on small  faceplates which  
are furnished with all new lathes4 ,the 
threaded size is  then taken and        
transferred with a micrometer1 over the 
anvil of which is  fitted a #fj-;degree 
point as shown enlarged at ,a4 ,in      
connection with a  graduated cross-feed 
screw this greatly facilitates the work 
over the usual  cut-and-try method4#ah  
,inside ,micrometer    ,the inside      
micrometer shown in sections in ,figs4  
#cd and #ce is adapted to  measuring1 by
 use of extension rods1 from #b inches  
up to any size of hole1  and has one    
inch adjustment of the measuring screw4 
,illustration3 #ce    ,referring to the 
section shown in ,fig4 #ce1 the         
measuring screw ,s is  secured to the   
thimble ,b with the screw ,d1 the head  

of which is  hardened and forms the     
anvil4 ,by loosening this screw ,d1 the 
thimble can  be rotated to compensate   
for wear4 ,the wear of the measuring    
screw and nut  is taken up by screwing  
the bushing ,a into the frame with the  
wrench  shown in ,fig4 #cg4 ,this       
bushing is split in three sections for  
about  two-thirds of its length on the  
threaded end4 ,the three small lugs on  
the  wrench fit into these slots4 ,the  
handle end of the wrench is a screw     
driver  which is used for manipulating  
the set screw ,c4 ,the bushing is made  
an  easy fit in the frame on its plain  
end and tapered1 as shown1 on its       
outside threaded part4 ,this thread     
being the same pitch as the measuring   
screw1 adjustment for wear does not     
affect the reading of the micrometer4   
,this manner of adjustment brings the   
nut squarely down on the measuring      
screw for its whole length1 presenting  
the same amount of wearing surface      
after adjustment as when new4           

,illustration3 ,fig4 #cf4 ,handle for   
,inside ,micrometer    ,illustration3   
,fig4 #cg4 ,wrench used with ,inside    
,micrometer    ,the point ,f1 which is  
hardened on its outer end1 screws into  
the frame1  and is secured by the       
taper-headed screw ,o1 which screws into
 and expands  the split and threaded end
 of the point ,f4 ,the handle1 ,fig4    
#cf1 clamps  over the knurled part of   
the frame for use in small1 deep holes4 
,the rods1  six in number1 running from 
#a to #f inches inclusive1 are made by  
screwing a  sleeve onto a rod with a    
hardened point and locking it with a    
taper-headed  screw on its threaded and 
split end1 the same as in the point ,f4 
,the  extension pieces1 ,fig4 #ch1 are  
adjustable1 on their socketed ends1 in  
the  same way1 and run in lengths of #f1
 #ab1 #ah inches1 etc4#ai               
,illustration3 ,fig4 #ch4 ,adjustable   
,extension ,pieces for ,inside          
,micrometer    ,direct                  
,fractional-reading ,micrometer         

,illustration3 ,fig4 #ci4 ,direct       
,fractional-reading ,micrometer    ,the 
direct fractional-reading micrometer    
shown in ,fig4 #ci is the result of     
talks with many mechanics in which all  
agreed that such a feature added to  a  
micrometer would1 by making it both a   
fractional and decimal gage1 more  than 
double its practical value4 ,while      
approximate readings in #fdths1 etc41   
may be obtained by the graduations on   
the barrel ,b as on an ordinary inch    
scale1 the exact readings of #fdth1     
etc41 may be obtained only by reference 
to graduations on the movable thimble   
,a4 ,there are but eight places on  ,a  
which coincide with the long graduation 
line on ,b when any #fdth1 #cb;d1       
#afth1 or #hth is being measured1 and   
each of these eight places is marked    
with a line1 and the #fdth1 #cb;d1      
#afth1 or #hth for which that line      
should be  used is marked thereon4 7,see
 a and b1 ,fig4 #dj47 ,the line a would 
be  used for #c_/cb1 #g_/cb1 #aa_/cb1   

etc41 and the line b for #a_/fd1 #i_/fd1
 #ag_/fd1  etc4 ,now suppose we wish to 
accurately measure #ae_/cb inch4 ,we    
first roughly  read it off the inch     
scale on sleeve ,b by turning out       
thimble ,a4 ,having  secured it closely 
by drawing edge of ,a over that         
graduation1 we find  that the line a    
7,fig4 #dj7 on the movable thimble very 
nearly or exactly  coincides with the   
long graduation line on ,b4 ,when these 
lines coincide1  we have the exact      
measurement of #ae_/cb inch without     
reference to how many  thousandths may  
be contained in the fraction4 ,thus all 
through the scale  any fraction may be  
found instantly4 ,there is no mental    
arithmetic1 use of  tables1 or memory   
work in using the tool4 ,the new        
graduations are  independent of the old1
 and may be used equally well with or   
without them4    ,illustration3 ,fig4   
#dj4 ,graduations on the                
,fractional-reading ,micrometer         
,micrometers may also be graduated as in

 ,fig4 #da4 ,instead of using the zero  
line on ,a as a base line1 a point is   
taken one-fifth of a turn around  ,a1   
and the graduated scale on ,b is placed 
to correspond1 as shown in  the         
engraving2 also1 instead of making lines
 a1 b1 etc41 on ,a1 full  length1 they  
are made about half an inch long1 and   
the numerators are  entirely omitted and
 the denominators placed at the end     
instead of under  the line4 ,to the     
ordinary user of the tool1 this is all  
that is necessary  for a perfectly clear
 reading of the fractions4#bj           
,illustration3 ,fig4 #da4 ,another      
,method of ,graduating for ,fractional  
,reading    ,sensitive ,attachment for  
,measuring ,instruments    ,no matter   
how finely and accurately micrometers   
and verniers may be made1  dependence   
must in all cases be placed on the      
sensitiveness of a man's hand  to obtain
 the exact dimensions of the piece to be
 measured4 ,in order to  overcome this  
difficulty and eliminate the personal   

equation in the  manufacture of         
duplicate and interchangeable parts1 the
 sensitive  attachment to the micrometer
 shown in ,fig4 #db may be used1 and    
will be  found of much value4           
,illustration3 ,fig4 #db4 ,sensitive    
,micrometer ,attachment    ,the         
auxiliary barrel ,a is held to the anvil
 of the micrometer by means of  a thumb 
screw ,b4 ,at the inside end of the     
barrel is a secondary anvil  ,c1 the    
base of which bears against the short   
arm of the indicating lever  ,d4 ,the   
action will be clearly seen by reference
 to the engraving4 ,the  micrometer is  
so set that when a gage1 ,g1 of exact   
size1 is placed  between the measuring  
points1 the long arm of the indicator   
stands at the #j  mark4 ,if the pieces  
being calipered vary in the least from  
the standard  size it will be readily   
noted by the movement of the pointer4   
,hard rubber  shapes turned from rough  
casting often vary from #j4jjc to #j4jje
 inch after  having passed the          

inspector's test with an ordinary       
micrometer4 ,with this  attachment the  
inspector's helper can detect very      
minute variations from  the limit size4 
,anything within the limits of the      
micrometer can be made to  show to the  
naked eye variations as small as a      
ten-thousandth inch4#ba    ,another     
,sensitive ,micrometer ,attachment      
,illustration3 ,fig4 #dc4 ,another      
,sensitive ,micrometer ,attachment      
,when testing the diameters of pieces   
that are handled in great quantities    
and are all supposed to be within       
certain close limits of a standard      
dimension1 the ordinary micrometer      
presents the difficulty of having to be 
moved for each piece1 and small         
variations in diameters have to be      
carefully read off from the graduations 
on the barrel4 ,not only does this  take
 a comparatively long time1 but it also 
easily happens that the  differences    
from the standard diameter are not      
carefully noted1 and pieces  are liable 

to pass inspection that would not pass  
if a convenient  arrangement for reading
 off the differences were at hand4 ,fig4
 #dc shows a  regular ,brown  ,sharpe   
micrometer fitted with a sensitive      
arrangement for  testing and inspecting 
the diameters of pieces which must be   
within certain  close limits of         
variation4 ,the addition to the ordinary
 micrometer is all  at the anvil end of 
the instrument4 ,the anvil itself is    
loose and consists  of a plunger ,b1    
held in place by a small pin ,a4 ,the   
pin has freedom to  move in a slot in   
the micrometer body1 as shown in the    
enlarged view in the  cut4 ,a spring ,c 
holds the plunger ,b up against the work
 to be measured1  and a screw ,d is     
provided for obtaining the proper       
tension in the spring4  ,the screw and  
the spring are contained in an extension
 ,e screwed and  doweled to the body of 
the micrometer4 ,a pointer or indicator 
is provided  which is pivoted at ,f and 
has one extensional arm resting against 

the pin  ,a1 which is pointed in order  
to secure a line contact4 ,at the end of
 the  indicator a small scale is        
graduated with the zero mark in the     
center1 and  as the indicator swings to 
one side or the other the variations in 
the size  of the piece measured are     
easily determined4 ,a small spring ,g is
 provided  for holding the pointer up   
against the pin ,a4 ,the case ,h simply 
serves  the purpose of protecting the   
spring mentioned4 ,as the plunger ,b    
takes up  more space than the regular   
anvil1 the readings of the micrometer   
cannot be  direct4 ,the plunger ,b can  
be made of such dimensions1 however1    
that #j4ajj  inch deducted from the     
barrel and thimble reading will give the
 actual  dimension4 ,such a deduction is
 easily done in all cases4 ,in other    
words1  the reading of the micrometer   
should be #j4ajj when the face of the   
measuring screw is in contact with the  
face of the plunger2 the #j4ajj inch    
mark is thus the zero line of this      

measuring tool4    ,when desiring to    
measure a number of pieces1 a standard  
size piece or gage  is placed between   
the plunger ,b and the face ,l of the   
micrometer screw1  and the instrument is
 adjusted until the indicator points    
exactly to zero  on the small scale     
provided on the body of the micrometer4 
,after this the  micrometer is locked1  
and the pieces to be measured are pushed
 one after  another between the face ,l 
and the plunger ,b1 the indications of  
the  pointer ,m being meanwhile         
observed4 ,whenever the pointer shows   
too great  a difference1 the piece1 of  
course1 does not pass inspection4 ,all  
deviations are easily detected1 and any 
person of ordinary common sense can  be 
employed for inspecting the work4       
,micrometer ,scale    ,illustration3    
,fig4 #dd4 ,micrometer ,mounted on      
,machinist's ,scale    ,a micrometer1   
mounted as shown in ,fig4 #dd is very   
handy4 ,the micrometer may  be used in  
combination with a #d-1 #f-1 #i-1 or    

#ab-;inch scale4 ,it can be  adjusted on
 standard plugs1 or one can make a set  
of gages up to #ab inches1  out of      
#c_/af-;inch round tool steel wire1 and 
use these for setting4 ,in  mounting the
 micrometer1 before cutting it apart1   
mill the shoulders shown  at ,a1 and in 
milling the bottom pieces ,b1 use a     
piece of machine steel  long enough for 
both1 cutting the piece in half after   
milling the slots4 ,in  this way one    
obtains perfect alignment4 ,in a shop   
where a set of large  micrometers is not
 kept1 this arrangement is very         
useful4#bb           99       99        
99       99       99      ,,chapter ,,iv
    ,,miscellaneous ,,measuring ,,tools 
,,and ,,gages    ,among the             
miscellaneous measuring tools and gages 
dealt with in this  chapter are tools   
and gages for measuring and comparing   
tapers1 adjustable  gages1 radius gages1
 gages for grinding drills1 sensitive   
gages1 tools for  gaging taper threaded 
holes1 contour gages1 etc4 ,of course1  

these are  offered merely as examples of
 what can be done in the line of        
measuring  tools for different purposes1
 and1 while having a distinct and direct
 value  to the mechanic1 they also have 
a great indirect value1 because they    
furnish suggestions for the designing   
and making of tools for similar         
purposes4    ,tool for ,measuring       
,tapers    ,illustration3 ,fig4 #de4    
,taper ,measuring ,tool    ,fig4 #de    
shows a tool which has proved very      
useful4 ,it is a tool for  measuring    
tapers on dowel pins1 reamers1 drill    
shanks1 or anything to be  tapered4     
,most machinists know that to find the  
taper of a shank they must  use their   
calipers for one end and reset them for 
the other end2 or else  caliper two     
places1 say1 three inches apart1 and if1
 for instance1 the  difference should be
 #a_/af inch1 they must multiply this   
difference by four  to get the taper per
 foot4 ,with the tool above mentioned1  
all this trouble  in calipering and     

figuring is saved4 ,simply place the    
shank or reamer to be  measured between 
pins ,a1 ,b1 ,c1 and ,d1 and slide ,h   
and ,k  together4 ,then the taper can be
 read at once on the graduated scale at 
,l4  ,the construction of the tool will 
be readily understood4 ,the body or base
  ,f has a cross piece supporting the   
two pins ,a and ,b4 ,on this slides     
piece ,k1 which has at its right end the
 graduated segment4 ,the screw ,g  is   
fast to piece ,k1 and upon it swivels   
the pointer ,e1 which carries  the two  
pins ,c and ,d4 ,thus these two pins can
 be brought into contact  with a tapered
 piece of any diameter within the       
capacity of the tool1 and  the swivel   
screw ,g allows the pins to adjust      
themselves to the taper of  the work and
 the pointer ,e to move to the left or  
right1 showing  instantly the taper per 
foot4    ,as the pins ,a and ,b are #a  
inch apart1 which is #a_/h of a foot1   
and the  distance from ,g to ,l is #d   
inches1 which is three times longer than

 the  distance between ,a and ,b1 the   
graduations should be #c_/fd inch apart1
 in  order to indicate the taper per    
foot in eighths of an inch4#bc    ,taper
 ,gage    ,illustration3 ,fig4 #df4     
,handy ,taper ,gage    ,a handy taper   
gage is shown in ,fig4 #df4 ,the blades 
of the gage are made of  tool steel4    
,the edge of the blade ,a is ,v-shaped1 
and the blade ,b has a  ,v-groove to    
correspond4 ,the end of ,b is offset so 
as to make the joint  and allow the two 
blades to be in the same plane4 ,a      
strong screw and nut  are provided to   
hold the blades at any setting4 ,the    
user of this gage looks  under the edge 
of ,a1 and is thereby enabled to tell   
whether the taper  coincides with that  
set by the gage1 and also where a taper 
piece needs  touching up to make it     
true4#bd    ,test ,gage for ,maintaining
 ,standard ,tapers    ,illustration3    
,fig4 #dg4 ,test ,gage for ,maintaining 
,standard ,tapers    ,in steam injector 
work1 accurately ground reamers of      

unusual tapers are  commonly required1  
and the gage shown in ,fig4 #dg was     
designed to maintain  the prevailing    
standard4 ,it consists of a graduated   
bar1 #a inch square1  with the slot ,f  
running its entire length4 ,the         
stationary head ,a is  secured in       
position flush with the end of the bar1 
and the sliding head ,b  is fitted with 
a tongue which guides it in the slot4   
,this head may be  secured in any       
desired position by means of a knurled  
thumb nut4 ,the  bushings ,d and ,d' are
 made of tool steel1 hardened and ground
 to a  knife edge on the inside flush   
with the face4 ,all bushings are made   
interchangeable as to outside diameter4 
,the head ,b is fitted with an          
indicating edge ,e which is set flush   
with  the knife edge of the bushing4    
,the reading indicates to #j4jaj inch   
the  distance the bushings are from each
 other1 and the difference in their     
diameter being known1 it is easy to     
compute the taper4 ,with this gage it is

  possible to maintain the standard     
tapers perfectly correct1 each reamer   
being marked with the reading as shown  
by the scale4#be    ,inside and ,outside
 ,adjustable ,gages    ,illustration3   
,fig4 #dh4 ,adjustable ,gage for ,inside
 and ,outside  ,measurements    ,fig4   
#dh shows an inside and an outside      
adjustable gage for accurate work1  used
 in laying out drill jigs1 and in       
setting tools on lathes1 shapers1       
planers1 and milling machines4 ,the     
outside gage is shown in the side view  
and in the sectional end view marked ,y4
 ,at ,x in the same figure is a         
sectional end view showing how the gage 
is constructed for inside work4 ,the    
top and bottom edges are rounded1 so    
that the diameters of holes may be      
easily measured4    ,the gage consists  
of a stepped block ,b1 mounted so as to 
slide upon the  inclined edge of the    
block ,c4 ,there are ,v-ways upon the   
upper edge of the  latter1 and the block
 ,b is split and arranged to clamp over 

the ways by  the screw shown at ,s4 ,all
 parts of the gage are hardened and the 
faces of  the steps marked ,a1 are      
ground and finished so that at any      
position of  the slide they are parallel
 to the base of the block ,c4 ,the lower
 split  portion of the block is         
spring-tempered to prevent breaking     
under the  action of the screw1 and also
 to cause it to spring open when        
loosened4 ,the  gage has the advantage  
that it can be quickly adjusted to any  
size within  its limits1 which does away
 with using blocks4 ,in planing a piece 
to a  given thickness1 the gage may be  
set to that height with great accuracy  
by  means of a micrometer caliper1 and  
then the planer or shaper tool adjusted 
down to the gage4 ,this method does away
 with the cut-and-try process1 and  will
 bring the finishing cut within #j4jja  
inch of the required size4 ,if the      
piece being planed1 or the opening to be
 measured1 is larger than the  extreme  
limit of the gage1 parallels may be     

used4 ,in fitting bushings into  bushing
 holes1 the adjustable gage may be moved
 out to fit the hole1 and  then1 when   
the bushing is finished to the diameter 
given by the gage1 as  determined by a  
micrometer caliper1 a driving fit is    
ensured4#bf    ,radius ,gage            
,illustration3 ,fig4 #di4 ,radius ,gage 
,fig4 #di shows a radius gage which has 
proved to be very handy for all such    
work as rounding corners or grinding    
tools to a given radius4 ,the blades    
are of thin steel1 and are fastened     
together at the end by a rivet1 thus    
forming a tool similar to the familiar  
screw pitch gage4 ,the right-hand       
corner of each blade is rounded off to  
the given radius1 while the  left-hand  
corner is cut away to the same radius1  
thus providing an  instrument to be used
 for either convex or concave surfaces4 
,the radius to  which each blade is     
shaped is plainly stamped upon the      
side4#bg    ,gage for ,grinding ,drills 
,illustration3 ,fig4 #ej4 ,gage for     

,grinding ,drills    ,fig4 #ej shows a  
gage for use in grinding drills1 which  
has been found very  handy and accurate4
 ,this gage enables either a large or   
small drill to lie  solidly in the      
groove provided for it on top of the    
gage1 and the lips can  then be tested  
for their truth in width1 or angle1 much
 easier and quicker  than with the gages
 in common use without the groove4      
,there is a line1 to  set the blade ,b  
by1 on the stock at an angle of #ei     
degrees at the top of  the graduated    
blade1 and the user can easily make     
other lines1 if needed  for special     
work4 ,the blade is clamped in position 
by the knurled nut ,n  at the back1 and 
can be thus adjusted to any angle4 ,the 
stock ,a is cut  away where the blade is
 pivoted on1 so that one side of the    
blade comes  directly in line with the  
middle of the groove4#bh    ,tool for   
,gaging ,taper ,threaded ,holes         
,illustration3 ,fig4 #ea4 ,tool for     
,gaging ,taper ,threaded ,holes    ,the 

tool shown in ,fig4 #ea is used for     
gaging taper threaded holes in  boilers 
when fitting studs4 ,it is a simple1    
though very useful and  economical tool1
 and it will doubtless be appreciated by
 those having much  work of this kind to
 do4 ,the hole in which the stud is to  
be fitted is  calipered by filling the  
threads of the plug with chalk1 and then
 screwing  the plug in the hole4 ,when  
the plug is removed the chalk will show 
exactly  the largest diameter of the    
hole4#bi    ,contour ,gage              
,illustration3 ,fig4 #eb4 ,setting      
,contour ,gage to ,turned ,sample       
,illustration3 ,fig4 #ec4 ,end ,view of 
,contour ,gage    ,figs4 #eb1 #ec and   
#ed illustrate a special tool which will
 be found of great  value in certain    
classes of work4 ,the need of some such 
device becomes  apparent when patterns  
and core boxes are required to be       
accurately checked  with the drawings of
 brass specialties1 in particular4 ,the 
tool is applied  to the work1 and the   

wires pressed down onto the contour by  
using the side  of a lead pencil4 ,of   
course1 patterns parted on the center   
could have their  halves laid directly  
on the drawing without using the contour
 gage1 but  some patterns are cored and 
inseparable4 ,such a tool proves a      
relentless  check upon the patternmaker1
 who1 by making the patterns larger than
  necessary1 can cause a considerable   
loss in a business where thousands of   
casts are made yearly from the same     
patterns4 ,as a ready and universal     
templet it is very useful4#cj           
,illustration3 ,fig4 #ed4 ,testing      
,core-box with ,gage    ,testing a      
,lead-screw    ,illustration3 ,fig4 #ee4
 ,micrometer for ,testing ,lathe        
,lead-screw    ,a reliable way for      
testing the pitch of a lead-screw1 at   
any position of  its length1 is to      
procure a micrometer screw and barrel   
complete1 such as  can be purchased from
 any of the manufacturers of accurate   
measuring  instruments1 and bore out a  

holder so that the axis of the          
micrometer screw  will be parallel to   
the holder when the screw is in place1  
as shown in ,fig4  #ee4 ,with the lathe 
geared for any selected pitch1 the nut  
engaged with the  lead-screw1 and all   
backlash of screw1 gears1 etc41 properly
 taken up1  clamp the micrometer holder 
to the lathe bed1 as shown in ,fig4 #ef1
 so that  the body of the holder is     
parallel to the carriage4 ,adjust the   
micrometer  to one inch when the point  
of the screw bears against the carriage 
and with  a surface gage scribe a line  
on the outer edge of the faceplate4 ,now
 rotate  the lathe spindle any number of
 full revolutions that are required to  
cause  the carriage to travel over the  
portion of the lead-screw that is being 
tested1 bringing the line on the        
faceplate to the surface gage point4 ,if
  the distance traveled by the carriage 
is not greater than one inch1 the       
micrometer will indicate the error      
directly4 ,for lengths of carriage      

travel  greater than one inch1 an end   
measuring rod1 set to the number of even
  inches required1 can be used between  
the micrometer point and lathe          
carriage4 ,the error in the lead-screw  
is then easily determined by the        
adjustment that may be required to make 
a contact for the measuring points      
between the carriage and the micrometer 
screw4 ,the pitch can be tested at  as  
many points as are considered necessary 
by using end measuring rods1 of  lengths
 selected1 set to good vernier calipers4
 ,the style of holder shown  can1 with  
the micrometer screw1 be used for       
numerous other shop tests1 and  as the  
screw is only held by friction caused by
 the clamping screw1 it can  easily be  
removed and placed in any form of holder
 that is found  necessary4#ca           
,illustration3 ,fig4 #ef4 ,testing a    
,lathe ,lead-screw    ,simple ,tool for 
,measuring ,angles    ,illustration3    
,fig4 #eg4 ,special ,tool for ,measuring
 ,angles    ,fig4 #eg shows a very      

simple1 but at the same time1 a very    
ingenious tool  for measuring angles4   
,strictly speaking1 the tool is not     
intended for  measuring angles1 but     
rather for comparing angles of the same 
size4 ,the  illustration shows so       
plainly both the construction and the   
application of  the tool1 that an       
explanation would seem superfluous4 ,it 
will be noticed  that any angle         
conceivable can be obtained in an       
instant1 and the tool can  be clamped at
 this angle by means of screws passing  
through the joints  between the straight
 and curved parts of which the tool     
consists4 ,linear  measurements can also
 be taken conveniently1 one of the      
straight arms of  the tool being        
graduated4 ,as both of the arms which   
constitute the actual  angle comparator 
are in the same plane1 it is all the    
easier to make  accurate comparisons4   
,this tool is of ,german design1 and is 
manufactured by  ,carl ,mahr1 ,esslingen
 a4 ,n4    ,bevel ,gear-testing ,gage   

,illustration3 ,fig4 #eh4 ,sensitive    
,gear-testing ,gage    ,in ,fig4 #eh is 
shown a sensitive gage for inspecting   
small bevel gears4 ,the  special case   
shown to which the gage is applied in   
the engraving is a small  brass miter   
gear finished on a screw machine1 in    
which case some of the  holes through   
the gears were not concentric with the  
beveled face of the  gears1 causing the 
gears to bind when running together in  
pairs4 ,the gage  shown is quite        
inexpensive1 but it indicates the       
slightest inaccuracy4           99      
99       99       99       99           
,,notes    #a ,,machinery1 ,october1    
#ahig4    #b ,m4 ,h4 ,ball1 ,april1     
#aijb4    #c ,m4 ,h4 ,ball1 ,february1  
#aija4    #d ,harry ,ash1 ,april1 #aijj4
    #e ,m4 ,h4 ,ball1 ,march1 #aijc4    
#f ,ezra ,f4 ,landis1 ,may1 #aijb4    #g
 ,l4 ,s4 ,brown1 ,march1 #aijc4    #h   
,c4 ,w4 ,putnam1 ,october1 #aija4    #i 
,jos4 ,m4 ,stabel1 ,may1 #aijc4    #aj  
,jos4 ,m4 ,stabel1 ,may1 #aijc4    #aa  

,jos4 ,m4 ,stabel1 ,may1 #aijc4    #ab  
,jos4 ,m4 ,stabel1 ,may1 #aijc4    #ac  
,p4 ,l4 ,l4 ,yorgensen1 ,february1      
#aijh4    #ad ,a4 ,l4 ,monrad1          
,december1 #aijc4    #ae ,a4 ,l4        
,monrad1 ,december1 #aijc4    #af ,a4   
,l4 ,monrad1 ,december1 #aijc4    #ag   
,j4 ,l4 ,marshall1 ,february1 #aijh4    
#ah ,charles ,sherman1 ,november1 #aije4
    #ai ,m4 ,h4 ,ball1 ,may1 #aijc4     
#bj ,chas4 ,a4 ,kelley1 ,may1 #aijh4    
#ba ,h4 ,j4 ,bachmann1 ,december1 #aijb4
    #bb ,wm4 ,ainscough1 ,may1 #aijh4   
#bc ,john ,aspenleiter1 ,october1 #aijj4
    #bd ,w4 ,w4 ,cowles1 ,june1 #aija4  
#be ,i4 ,b4 ,niemand1 ,december1 #aijd4 
#bf ,geo4 ,m4 ,woodbury1 ,february1     
#aijb4    #bg ,a4 ,putnam1 ,july1 #aijc4
    #bh ,m4 ,h4 ,ball1 ,october1 #aija4 
#bi ,f4 ,rattek1 ,january1 #aijh4    #cj
 ,howard ,d4 ,yoder1 ,december1 #aijg4  
#ca ,w4 ,cantelo1 ,july1 #aijc4