|
General Purpose
With clearance on all diameters for free movement, general purpose Acmes are used for a wide variety of parts including all types of vise and jack screws where holding major diameter is not a critical consideration. Three classes of thread fit tolerances are available: 2G, 3G and 4G.
Download PDF
|
|
Centralizing
Centralizing Acmes have limited clearance at the major diameter of screw and nut and are used extensively for feed screws. The limited clearance enables a bearing at the major diameter to maintain alignment of the thread axis, preventing wedging on the flanks and part sagging.
Five classes are used: 2C, 3C, 4C, 5C, and 6C. Classes 5C and 6C are designed to allow limited backlash, though some backlash will be experienced with any of these classes.
Download PDF
|
|
"Stub" Acme
The Stub Acme is generally used for applications where a coarse pitch thread of shallow depth must be used due to mechanical or metallurgical considerations. A standard 1-1/2 - 5P Acme is planned for a specific part, but the amount of metal removal would reduce the minor diameter to the point where the torque would twist the part. The solution: use a 1-1/2", 5-pitch two start, or 1-1/2", 5-pitch stub Acme. Thread height for standard stub Acmes is equal to 0.3 times the pitch, while the height of a standard Acme is 1/2 of the pitch. Otherwise, the forms are identical.
Download PDF
|
|
Modified "Stub" Acme
Basic data for two other commonly used forms have been tabulated. These are designated Modified Forms 1 and 2. Always use the Standard Stub Acme form in preference to the Modified forms where it is practical.
M1 – the pitch and minor diameters are smaller than the standard form values.
M2 – the pitch and minor diameters are larger than the standard form values.
Download PDF
For more information about Acme Thread Tooling, contact Customer Service at 800.358.3500.
|
The Landis system for cutting Acme threads provides the greatest latitude in tool operation and the surest method for cutting Acme threads, compared to other methods.
