Used for checking tool angles while machining threads, this gage is made from polished stainless steel. Clearly marked on the gage are references for Whitworth, BSF, B.A., Metric, American National, and Acme thread angles.

Angles included are 55 degrees (Whitworth & BSF), 47.5 degrees (B.A.), 60 degrees (American National/Acme, and Metric), and 14.5 degrees (Acme).