Telescoping gauges are used to gauge large holes and to measure inside distances. These gauges are equipped with a plunger that can be locked in the measuring position by a knurled screw or locking nut in the end of the handle. Maximum measuring capacity is 6". Measurements must be calipered on the gauge by a micrometer, as in the case of the small hole gauges. They are also used when measurements cannot be taken with a standard micrometer. Telescoping gauges are particularly adaptable for roughly bored work and odd sizes and shapes of holes.
To use the telescoping gauge loosen the knurled locking nut at the end of the handle. Compress the plungers, place them into the hole to be measured, release the turning handle screw, slightly tilt the telescoping gauge, and rock it back and forth slightly, while at the same time gradually tightening the turning handle screw. Remove the gauge from the hole. Take measurements only once. Repeated attempts will produce an inaccurate reading. Measure the gauge setting with an outside micrometer. Made of hardened steel.
Includes 6 gauges (5/16" to 6" range).