Starrett Depth gages
No. 643 Dial Depth Gage
This gage has a knife-edge base and a needle point contact which has been hardened and ground.
The knife-edge base has a cutout so that the conical point can be precisely positioned for close work.
Point is 1/2" (12.7mm) long with a 40

Starrett 52714 Small Depth Gauges Starrett Depth gauges Graduation:.0005" Dial Reading:0-25-0 Range:0-.125"