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Acme Thread

What is Acme Thread? It is defined as the screw thread when thread is having a twenty nine degree angel incorporated. Acme thread is widely utilized for feed and adjusting screws on industrial equipment and accessories.

The Shape of Acme thread: This thread type has a twenty nine degrees angle thread with a pitch doubled to that of thread height; whilst the crest and trough are flat. This form is convenient to machine (quicker shearing, extended tool span) which is a thread square.

The tooth outlier additionally has a broader foundation which explicates itself that it is robust (therefore, the screw can maintain itself with a higher load) than a correspondingly square thread of the same dimension. Such thread shapes additionally permit for the implementation of a fragmented nut, which can recompense for nut wear.

Also read about Addendum.

Classes of Acme Threads: There are three types of Universal Function ACME threads which are 2G, 3G, and 4G. Every type allows specific clearance on all typical magnitude diameters for unrestricted movement, and is utilized in assemblages with the inner thread firmly founded and drive of the exterior thread in a course at right angles to its axis restricted by bearings.


Selection of the Class Threads: ACME Thread Universal Function Manufacturing Calculator will specify the type of Universal Function thread to be utilized i.e. 2G, 3G, or 4G, for the exterior and inner threads. In use, it is recommended that outer and inner threads of the similar type be utilized together for universal function assemblages; Class 2G being the favored selection as far as the experts are concerned. If minimized repercussion or end play is needed, General Classes 3G and 4G can be selected.


Engineer Ali Alvi is an industrial engineer who has post graduated from the NED University, then completed his Masters in Industrial Engineering from the University of Ontario. He has also served as an engineer in International Steel Ltd as A Cold rolling mill engineer.

  1. Timothy William Burns says:

    We are seeing a rough surface finish like the tread was a rip or torn finish on the 29 degree contact surface. Is there a Ra on the contact surface?

  2. Mohamed says:

    Dear Sir,
    Kindly need your support to communicate with the sales department of the company ( ACME & Stub ACME Threads) in order to obtain their license and then we communicate with you to request ACME Thread Gauges

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