ACME Thread Pitch
ACME threads are designed for transversal motion. Typical applications are vises and jack screw applications. They have wide trapezoidal thread crests that make motion possible.
ACME thread pitches are measured in TPI (Threads per Inch) which is measured by finding the number of thread crests in 1" of threads.
Other Names: Trapezoidal Thread
Types:
General Purpose: The common type with a standard amount of clearance in the thread form. Example: 2G, 3G, 4G.
Centralizing: A type of ACME with tighter tolerances used for feed screws. Example: 2C, 3C, 4C, 5C.
*The table below shows only standard sizes. Some other sizes exist for special applications
| Dia. | TPI | Decimal |
|---|---|---|
| 1/4 | 16 | 0.2500 |
| 5/16 | 14 | 0.3125 |
| 3/8 | 12 | 0.3750 |
| 7/16 | 12 | 0.4375 |
| 1/2 | 10 | 0.5000 |
| 5/8 | 8 | 0.6250 |
| 3/4 | 6 | 0.7500 |
| 7/8 | 6 | 0.8750 |
| 1 | 5 | 1.0000 |
| 1 1/8 | 5 | 1.1250 |
| 1 1/4 | 5 | 1.2500 |
| Dia. | TPI | Decimal |
|---|---|---|
| 1 3/8 | 4 | 1.3750 |
| 1 1/2 | 4 | 1.5000 |
| 1 3/4 | 4 | 1.7500 |
| 2 | 4 | 2.0000 |
| 2 1/4 | 3 | 2.2500 |
| 2 1/2 | 3 | 2.5000 |
| 2 3/4 | 3 | 2.7500 |
| 3 | 2 | 3.0000 |
| 4 | 2 | 4.0000 |
| 5 | 2 | 5.0000 |