TYPES AND USES - Continued
SCREW PITCH GAGES
Screw pitch gages are made for checking the pitch of
U.S. Standard, Metric, National Form, V-form, and
Whitworth cut threads. These gages are grouped in a
case or handle, as are the thickness gages. The
number of threads per inch is stamped on each blade.
Some types are equipped with blade locks. The
triangular shaped gage has 51 blades covering a wide
range of pitches, including 11-1/2 and 27 threads-per-
inch for V-form threads.
Screw pitch gages are used to determine the pitch of an
unknown thread. The pitch of a screw thread is the
distance between the center of one tooth to the center of
the next tooth.
SMALL HOLE GAGE SET
Small hole gages are adjustable, having a rounded
measuring member. A knurled screw in the end of the
handle is turned to expand the ball-shaped end in small
holes and recesses. A micrometer caliper is used to
measure the ball end. Maximum measuring capacity is
1/2 inch. This set of 4 or more gages is used to check
dimensions of small holes, slots, grooves, and so forth
from approximately 1/8 to 1/2 inch in diameter.
Telescoping gages are used to gage larger holes and to
measure inside distances. These gages are equipped
with a plunger (1) that can be locked in the measuring
position by a knurled screw (2) in the end of the handle
(3). Maximum measuring capacity is 6 inches.
Measurements must be calipered on the gage by a
micrometer, as in the case of the small hole gages.
They are also used when measurements cannot be
taken with a standard micrometer. Telescoping gages
are particularly adaptable for roughly bored work and
odd sizes and shapes of holes. Compress the plungers