ACME and trapezoidal threaded products appear similar at a glance. In fact, these two threads were developed around the same time and are more similar than different. What is the difference between ACME thread and trapezoidal thread, and which should you choose?
Until the late 1800s, square threads were in common use for heavy loads and motion transfer applications. There were two problems with square threads, however. The threads were difficult to manufacture with the technology available at the time, and they tended to be weak. These short comings led to the development of the ACME thread in the late 1800s.
The ACME thread design featured a 29-degree thread angle which provided for a wider base that was stronger than the base on square threads. Common standards were eventually developed for ACME diameters and thread pitches. These standards established diameter in Imperial inches and thread count in threads-per-inch measurements. A6.35 lead screw as example.
A similar set of standards was developed in Europe. The difference between the two is that the European standards relied on metric units of measurement, Tr8 for instance. As a result, the trapezoidal thread standard that was adopted in Europe has a 30-degree thread angle instead of the 29-degree thread angle that was adopted in the U.S.
ACME and trapezoidal threaded products are used for similar applications. Both are frequently used in machinery as lead screws for lathes, jacks, jack stands, vices, and similar products. In some cases, it may be possible to even use ACME and trapezoidal threaded products interchangeably provided the thread count is the same.
ACME threads have become widely used globally and are an accepted standard. As a general rule, when choosing between ACME and trapezoidal threads, you will probably want to consider where the parts will be produced and used.
Dependable ACME specializes in the manufacture of high-quality, ACME threaded products. We have more than 55 years of experience in the threaded products industry, and offer a variety of ACME threaded products. Contact us at 800-893-3792 to learn how we can meet your ACME thread needs.
This time why Europe keen to use metric standard but US bias on ACME?
