Starrett Acme Standard Screw
Thread Gage - Hardened
Acme Standard Screw Thread Gage - Hardened by Starrett
No. 284 29°
This gage is a standard for grinding and setting tools when cutting Acme threads. Acme threads have the same depth as square threads but the sides of the threads are at an inclination of 14-1/2° (29° included angle). This form of thread is used
extensively and has in many instances replaced the square thread in machine construction. The advantages of the Acme thread are its strength and the ease by which it can be cut compared with square threads. The angles and edges of this gage are hardened,
ground and carefully tested.
In use, the angle on the thread cutting tool is checked on the large precision-ground V at the end of the gage. The tool is then ground on the end to the width of the slot of whatever pitch is being turned. It is then set in the lathe using the half