Gear Tooth Calipers

The gear tooth caliper is exactly what the name imlies : a specialized caliper used exclusively for measuring the cord thickness of gear teeth at the tooth’s pitch diameter. Taken in this light , the gear tooth caliper acts as both a vernier depth gauge and a vernier caliper .The vertical slide acts as the depth gauge and the horizontal slide acts as the vernier caliper. The vernier scales on each of these slides are read like any other vernier scale.
This instrument is predominantly a checking instrument. First , the depth of the pitch diameter is set on the vertical slide and the slide is locked in place with the clamping screw. The instrument is then placed down over the gear tooth, and the horizontal slide caliper is closed and adjusted over the cord of the gear tooth . The caliper can then be locked in place and removed to take the measurement reading.