Lesson 4/Learning Event
Small Hole and Telescoping
a. Use these gages when measurements cannot be taken with a standard
b. Telescoping gages are particularly adaptable for rough bored work
and odd sizes and shapes of holes.
c. Use compress plungers and lock by turning the handle screw. Insert
the gage in the hole, Figure 59. Release the lock and the plunger
expands to the exact size of the hole. Lock the plunger by turning
After locking the plunger, remove the gage and check
the measurement with a micrometer.
USING TELESCOPING GAGE
d. Small hole gages perform the same function as telescoping gages
except that they are used in small work.
e. To use the small hole gage, fit the ball-shaped point into the hole
or slot, Figure 60, Part A. Expand the ball-shaped end by turning
the screw at the end of the handle.
f. Use a micrometer to gage the measurement, Figure 60, Part B.
USING SMALL HOLE GAGE (PARTS A AND B)