INSIZE 4810-55 Center Gauge Whitworth 55 Degrees

The INSIZE 4810-55 is a stainless steel center gauge ground to the 55° angle of a Whitworth screw thread, used to check and set the angle on screw-cutting lathe tools and to check the angle and pitch of a finished thread. INSIZE states an angle accuracy of ±30 minutes of arc. Its blade carries threads-per-inch scales on both faces: 14 and 20 TPI on the front, 24 and 32 TPI on the back, for checking a Whitworth thread's pitch directly against the workpiece. It is a standard toolroom and lathe-side gauge for setting up Whitworth threading work.