American trapezoidal thread

There are two types of trapezoidal thread specifications, namely American trapezoidal thread (ACME, also known as ACME thread) with an Asan angle of 29°, and 30° Metric trapezoidal thread. Although the transmission efficiency of trapezoidal threads is lower than that of square threads, because square threads are not easy to process and manufacture, trapezoidal threads are generally used for transmission screws.

In the American ASME/ANSI B1.5 standard, the universal dimensions of ACME trapezoidal threads are defined, which are divided into 2G, 3G, and 4G according to the clearance tolerance of internal and external threads. Grade, it is recommended that the internal and external threads adopt the same tolerance grade. Generally, 2G is preferred. If less clearance is required, 3G or 4G is used.