Gear Tooth vernier calipers
Gear Tooth vernier calipers is designed to measure in .001″or 0.02mm
the thickness of gear teeth at the pitch line (the chordal thickness
of the teeth) using the distance from the top of a tooth to the
chord. For the same purpose, it can also be used for measuring hobs,
from and thread tools,etc.
The thickness of a tooth at the pitch line is measured by an
adjustable tongue. Each of these is adjusted independently by screws
on the graduated bars.
For tool operation:
a. Furnished with the tool, the number of teeth of the gear in
question, and find the corrected addendum(s�?. This figure is for
one diametral pitch for inch measure, so multiply it by the required
moduel number. This gives a corrected addendum for this particular
number of teeth.
b. Next, measure the actual outside diameter of the gear and add or
subtract one-half the diffence between the theoretical gear diameter
and actual measured gear diameter from corrected addendum(s�? found
in the first step.
c. Set the new calculated addendum figure on the adjustable tong of
the tool.
d. Now, with the tongue on the top of the tooth, measure the chordal
thickness with the horizontal vernier jaw and compare with the
figure in the “t�?.
e. All inch graduations are read to .001�?