The Starrett 456BZ Gear Tooth Vernier Caliper is designed to measure in .001" or 0.02mm the thickness of gear teeth at the pitch line (the chordal thickness of the teeth) using the distance from the top of a tooth to the chord. For the same purpose, it can also be used for measuring hobs, form and thread tools and more. 10-1 Diametral Pitch in case. This gage can be independently adjusted by screws on the graduated bars. Has a measuring range of 0 to 1-1/4" with .001" graduations.
Can be used for measuring hobs, form and thread toolsAdjusted independently by screws on the graduated barsThickness of a tooth at the pitch line is measured by an adjustable jaw after the addendum is set by the adjustable tongue