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 tapers, adjustable
gages, radius gages, gages for grinding drills, sensitive gages, tools for
gaging taper threaded holes, contour gages, etc. Of course, these are
offered merely as examples of what can be done in the line of measuring
tools for different purposes, and, while having a distinct and direct value
to the mechanic, they also have a great indirect value, because they
furnish suggestions for the designing and making of tools for similar
purposes.
Tool for Measuring Tapers
[Illustration: Fig. 45. Taper Measuring Tool]
Fig. 45 shows a tool which has proved very useful. It is a tool for
measuring tapers on dowel pins, reamers, drill shanks, or anything to be
tapered. 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 end; or else
caliper two places, say, three inches apart, and if, for instance, the
difference should be 1/16 inch, they must multiply this difference by four
to get the taper per foot. With the tool above mentioned, all this trouble
in calipering and figuring is saved. Simply place the shank or reamer to be
measured between pins _A_, _B_, _C_, and _D_, and slide _H_ and _K_
together. Then the taper can be read at once on the graduated scale at _L_.
The construction of the tool will be readily understood. The body or base
_F_ has a cross piece supporting the two pins _A_ and _B_. On this slides
piece _K_, which has at its right end the graduated segment. The screw _G_
is fast to piece _K_, and upon it swivels the pointer _E_, which carries
the two pins _C_ and _D_. Thus these two pins can be brought into contact
with a tapered piece of any diameter within the capacity of the tool, 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 right, showing
instantly the taper per foot.
As the pins _A_ and _B_ are 1½ inch apart, which is 1/8 of a foot, and the
distance from _G_ to _L_ is 4½ inches, which is three times longer than the
distance between _A_ and _B_, the graduations should be 3/64 inch apart, in
order to indicate the taper per foot in eighths of an inch.[23]
Taper Gage
[Illustration: Fig. 46. Handy Taper Gage]
A handy taper gage is shown in Fig. 46. The blades of the gage are made of
tool steel. The edge of the blade _A_ is V-shaped, and the blade _B_ has a
V-groove to correspond. The end of _B_ is offset so as to make the joint
and allow the two blades to be in the same plane. A strong screw and nut
are provided to hold the blades at any setting. The user of this gage looks
under the edge of _A_, and is thereby enabled to tell whether the taper
coincides with that set by the gage, and also where a taper piece needs
touching up to make it true.[24]
Test Gage for Maintaining Standard Tapers
[Illustration: Fig. 47. Test Gage for Maintaining Standard Tapers]
In steam injector work, accurately ground reamers of unusual tapers are
commonly required, and the gage shown in Fig. 47 was designed to maintain
the prevailing standard. It consists of a graduated bar, 1 inch square,
with the slot _F_ running its entire length. The stationary head _A_ is
secured in position flush with the end of the bar, and the sliding head _B_
is fitted with a tongue which guides it in the slot. This head may be
secured in any desired position by means of a knurled thumb nut. The
bushings _D_ and _D'_ are made of tool steel, hardened and ground to a
knife edge on the inside flush with the face. All bushings are made
interchangeable as to outside diameter.
The head _B_ is fitted with an indicating edge _E_ which is set flush with
the knife edge of the bushing. The reading indicates to 0.010 inch the
distance the bushings are from each other, and the difference in their
diameter being known, it is easy to compute the taper. With this gage it is
possible to maintain the standard tapers perfectly correct, each reamer
being marked with the reading as shown by the scale.[25]
Inside and Outside Adjustable Gages
[Illustration: Fig. 48. Adjustable Gage for Inside and Outside
Measurements]
Fig. 48 shows an inside and an outside adjustable gage for accurate work,
used in laying out drill jigs, and in setting tools on lathes, shapers,
planers, and milling machines. The outside gage is shown in the side view
and in the sectional end view marked _Y_. At _X_ in the same figure is a
sectional end view showing how the gage is constructed for inside work. The
top and bottom edges are rounded, so that the diameters of holes may be
easily measured.
The gage consists of a stepped block _B_, mounted so as to slide upon the
inclined edge of the block _C_. There are V-ways upon the upper edge of the
latter, and the block _B_ is split and arranged to clamp over the ways by
the screw shown at _S_. All parts of the gage are hardened and the faces of
the steps marked _A_, are ground and finished so that at any position of
the slide they are parallel to the base of the block _C_. The lower split
portion of the block is spring-tempered to prevent breaking under the
action of the screw, and also to cause it to spring open when loosened. The
gage has the advantage that it can be quickly adjusted to any size within
its limits, which does away with using blocks. In planing a piece to a
given thickness, the gage may be set to that height with great accuracy by
means of a micrometer caliper, and then the planer or shaper tool adjusted
down to the gage. This method does away with the "cut-and-try" process, and
will bring the finishing cut within 0.001 inch of the required size. If the
piece being planed, or the opening to be measured, is larger than the
extreme limit of the gage, parallels may be used. In fitting bushings into
bushing holes, the adjustable gage may be moved out to fit the hole, and
then, when the bushing is finished to the diameter given by the gage, as
determined by a micrometer caliper, a driving fit is ensured.[26]
Radius Gage
[Illustration: Fig. 49. Radius Gage]
Fig. 49 shows a radius gage which has proved to be very handy for all such
work as rounding corners or grinding tools to a given radius. The blades
are of thin steel, and are fastened together at the end by a rivet, thus
forming a tool similar to the familiar screw pitch gage. The right-hand
corner of each blade is rounded off to the given radius, while the
left-hand corner is cut away to the same radius, thus providing an
instrument to be used for either convex or concave surfaces. The radius to
which each blade is shaped is plainly stamped upon the side.[27]
Gage for Grinding Drills
[Illustration: Fig. 50. Gage for Grinding Drills]
Fig. 50 shows a gage for use in grinding drills, which has been found very
handy and accurate. This gage enables either a large or small drill to lie
solidly in the groove provided for it on top of the gage, and the lips can
then be tested for their truth in width, or angle, much easier and quicker
than with the gages in common use without the groove. There is a line, to
set the blade _B_ by, on the stock at an angle of 59 degrees at the top of
the graduated blade, and the user can easily make other lines, if needed
for special work. The blade is clamped in position by the knurled nut _N_
at the back, and can be thus adjusted to any angle. The stock _A_ is cut
away where the blade is pivoted on, so that one side of the blade comes
directly in line with the middle of the groove.[28]
Tool for Gaging Taper Threaded Holes
[Illustration: Fig. 51. Tool for Gaging Taper Threaded Holes]
The tool shown in Fig. 51 is used for gaging taper threaded holes in
boilers when fitting studs. It is a simple, though very useful and
economical tool, and it will doubtless be appreciated by those having much
work of this kind to do. The hole in which the stud is to be fitted is
calipered by filling the threads of the plug with chalk, and then screwing
the plug in the hole. When the plug is removed the chalk will show exactly
the largest diameter of the hole.[29]
Contour Gage
[Illustration: Fig. 52. Setting Contour Gage to Turned Sample]
[Illustration: Fig. 53. End View of Contour Gage]
Figs. 52, 53 and 54 illustrate a special tool which will be found of great
value in certain classes of work. The need of some such device becomes
apparent when patterns and core boxes are required to be accurately checked
with the drawings of brass specialties, in particular. The tool is applied
to the work, and the wires pressed down onto the contour by using the side
of a lead pencil. Of course, patterns parted on the center could have their
halves laid directly on the drawing without using the contour gage, but
some patterns are cored and inseparable. Such a tool proves a relentless
check upon the patternmaker, who, by making the patterns larger than
necessary, can cause a considerable loss in a business where thousands of
casts are made yearly from the same patterns. As a ready and universal
templet it is very useful.[30]
[Illustration: Fig. 54. Testing Core-box with Gage]
Testing a Lead-screw
[Illustration: Fig. 55. Micrometer for Testing Lathe Lead-screw]
A reliable way for testing the pitch of a lead-screw, at any position of
its length, is to procure a micrometer screw and barrel complete, such as
can be purchased from any of the manufacturers of accurate measuring
instruments, and bore out a holder so that the axis of the micrometer screw
will be parallel to the holder when the screw is in place, as shown in Fig.
55. With the lathe geared for any selected pitch, the nut engaged with the
lead-screw, and all backlash of screw, gears, etc., properly taken up,
clamp the micrometer holder to the lathe bed, as shown in Fig. 56, so that
the body of the holder is parallel to the carriage. 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 faceplate. 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
tested, bringing the line on the faceplate to the surface gage point. If
the distance traveled by the carriage is not greater than one inch, the
micrometer will indicate the error directly. For lengths of carriage travel
greater than one inch, an end measuring rod, set to the number of even
inches required, can be used between the micrometer point and lathe
carriage. 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 screw. The pitch can be tested at
as many points as are considered necessary by using end measuring rods, of
lengths selected, set to good vernier calipers. The style of holder shown
can, with the micrometer screw, be used for numerous other shop tests, and
as the screw is only held by friction caused by the clamping screw, it can
easily be removed and placed in any form of holder that is found
necessary.[31]
[Illustration: Fig. 56. Testing a Lathe Lead-screw]
Simple Tool for Measuring Angles
[Illustration: Fig. 57. Special Tool for Measuring Angles]
Fig. 57 shows a very simple, but at the same time, a very ingenious tool
for measuring angles. Strictly speaking, the tool is not intended for
measuring angles, but rather for comparing angles of the same size. The
illustration shows so plainly both the construction and the application of
the tool, that an explanation would seem superfluous. It will be noticed
that any angle conceivable can be obtained in an instant, 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 consists. Linear
measurements can also be taken conveniently, one of the straight arms of
the tool being graduated. As both of the arms which constitute the actual
angle comparator are in the same plane, it is all the easier to make
accurate comparisons. This tool is of German design, and is manufactured by
Carl Mahr, Esslingen a. N.
Bevel Gear-testing Gage
[Illustration: Fig. 58. Sensitive Gear-testing Gage]
In Fig. 58 is shown a sensitive gage for inspecting small bevel gears. The
special case shown to which the gage is applied in the engraving is a small
brass miter gear finished on a screw machine, in which case some of the
holes through the gears were not concentric with the beveled face of the
gears, causing the gears to bind when running together in pairs. The gage
shown is quite inexpensive, but it indicates the slightest inaccuracy.
* * * * *
NOTES
[1] MACHINERY, October, 1897.
[2] M. H. Ball, April, 1902.
[3] M. H. Ball, February, 1901.
[4] Harry Ash, April, 1900.
[5] M. H. Ball, March, 1903.
[6] Ezra F. Landis, May, 1902.
[7] L. S. Brown, March, 1903.
[8] C. W. Putnam, October, 1901.
[9] Jos. M. Stabel, May, 1903.
[10] Jos. M. Stabel, May, 1903.
[11] Jos. M. Stabel, May, 1903.
[12] Jos. M. Stabel, May, 1903.
[13] P. L. L. Yorgensen, February, 1908.
[14] A. L. Monrad, December, 1903.
[15] A. L. Monrad, December, 1903.
[16] A. L. Monrad, December, 1903.
[17] J. L. Marshall, February, 1908.
[18] Charles Sherman, November, 1905.
[19] M. H. Ball, May, 1903.
[20] Chas. A. Kelley, May, 1908.
[21] H. J. Bachmann, December, 1902.
[22] Wm. Ainscough, May, 1908.
[23] John Aspenleiter, October, 1900.
[24] W. W. Cowles, June, 1901.
[25] I. B. Niemand, December, 1904.
[26] Geo. M. Woodbury, February, 1902.
[27] A. Putnam, July, 1903.
[28] M. H. Ball, October, 1901.
[29] F. Rattek, January, 1908.
[30] Howard D. Yoder, December, 1907.
[31] W. Cantelo, July, 1903.