PRECISION MEASURING AND GAGING - OD1642 - LESSON 1/TASK 2
PROTRACTOR VERNIER SCALE READINGS.
(3) Use and Application. The bevel protractor is used to measure the
angular clearance on a ring gear (figure 50, view A, on the following page).
The bevel protractor can be used to establish an angle and determine its
relationship to other surfaces as shown in figure 50, view B.
angle attachment is connected to the slotted extension of the dial and is
used to accurately measure acute angles as shown in figure 50, view C.
Gear Tooth Vernier Caliper.
(1) A gear tooth vernier (figure 51, views A and B, on page 80) is
used to measure the chordal thickness of a gear tooth on the pitch circle
and the distance from the top of the tooth to the pitch chord (chordal
addendum) at the same time. The vernier scale on this tool is read in the
same way as other verniers, except that graduations on the main scale are
0.020 inch apart instead of 0.025 of an inch.