Lesson 2/Learning Event 1
a. Spring calipers, Figures 18 and 19, are available in sizes from 2 to
8 inches. The friction of the adjusting nut and screw works against
the tension of the spring which holds the legs in any set position.
This type of caliper is known as the toolmaker's spring caliper.
b. Thread spring calipers are used to measure diameters and distances
in tapped holes. The ends of the legs of thread calipers are shaped
to a fine point so that exact contact can be made between threads.
Firm joint calipers are available in a number of sizes from 3 to 24 inches.
This type of caliper is equipped with a nut and stud that provides
sufficient friction to hold the legs in any set position.
Some of these
calipers are equipped with an adjusting screw for fine adjustments.
Transfer Firm Joint
Transfer firm joint calipers are shaped for inside measurements and are used
for measuring recesses where the setting cannot be transferred to a scale
directly because the legs must be collapsed to remove them from the work.
inside caliper. They have one leg of each device. These calipers are used
for scribing parallel lines from an edge or for locating the center of
cylindrical work. Some are equipped with an adjustable point.