What is the ACME thread gauge?

It is a thread gauge that’s used to gauge external and internal threaded products, and they’re priced or can be priced on the petition. The thread below has been precisely chosen to meet certain prerequisites with the least number of items to keep the inventory of tooling and gauges.

Other size collection including centralizing threads, centralized stub Acme, Stub Acme, multiple start thread, and diameters over 5 inches can be priced, and Acme thread has three classes, which include- 2G, 3G, and 4G.

These class of gauges is made with clearance on all types of a diameter which enhance free movement. These threads are quite suitable and good for assemblies where the internal thread is rightly fixed, and the external thread moves to its perpendicular axis. It is highly advised that threads of the same class should be built together. The most popular thread class of fit is class 2G. Class 3G and 4G should always be used in case backlash are needed.

Acme thread gauges are specified by the letter C and the other classes of fit that are specified as 2C, 3C, and 4C.

The other types of threads are Centralizing Stub Acme, and Stub Acme and all Acme threads have 29 degrees included angle.

The abbreviations that will be listed below are approved for the exact thread terminology on tools, drawings, and gauges.

C means centralizing.

G means general purpose

L means lead

LH means left hand

ACME means ACME Threads

The measurement of pitch diameter for Stub and Acme and thread gauges can be used for threads that have an angle of less than 5 degrees.


The full name of NPT thread gauge is National Pipe Taper thread gauges, and the full name is American National Standard Taper Pipe Thread Gauges.

NPT thread gauges are mostly used in threaded pipe fittings and pipes, and they’re tapered for sealing that need no thread sealant. Each of NPT thread gauge is 100% calibrated with quality proof.

For NPT thread gauge, the taper is just an inch diameter in 16 inches of length, i.e., 3/4 inch per foot, which is measured by the change of diameter over the distance of the thread.

The angle that’s between the center axis of taper is tan−1( 1⁄32) = 1.7899° = 1° 47′ 24″.