THREADING INSERTS – ACME – STUB ACME
Firstly, Acme are threads with small profile angles. The acme thread form has three main classes: General Purpose (G), Centralizing (C), and Stub Acme. The General Purpose and Centralizing thread forms have a nominal depth of thread of 0.50 × pitch. They also have a 29° included thread angle. Stub Acme threads are also of the same basic design, but have a thread depth less than one half the pitch.