1/4-16 ACME thread: 6.35 mm × 16 TPI
Threads › 1/4-16 ACME
1/4-16 ACME is an Acme thread: 6.35 mm major diameter, 16 TPI (1.588 mm pitch), 29° form.
| Standard | Acme |
|---|---|
| Major diameter | 6.35 mm (0.25″) |
| Pitch | 16 TPI (1.588 mm) |
| Thread angle | 29° |
| Minor diameter, bolt | 4.25 mm |
| Minor diameter, nut | 4.25 mm |
| Tap drill | Not listed. Check your tap maker's chart. |
Minor diameters worked out from the basic profile: major Ø − pitch − 0.508 mm.
Open 1/4-16 ACME in BenchsmithAdd to order list
Measure it
Bolt: Measure across the crests of the bolt with the caliper jaws. Worn bolts read 0.1 to 0.3 under.
Nut or tapped hole: Measure across the tops of the threads inside the nut or hole with the inside jaws. That is the minor Ø. Worn or oversize holes read a little over.
Close in size, won't mate
- 1/4-20 UNCØ6.35 mm, 20 TPI
- 1/4-28 UNFØ6.35 mm, 28 TPI
- 1/4 BSWØ6.35 mm, 20 TPI
- M6Ø6 mm, 1 mm pitch
- M6×0.75Ø6 mm, 0.75 mm pitch
- #12-24 UNCØ5.49 mm, 24 TPI
One size up or down
- 5/16-14 ACMEØ7.94 mm (up)
Got a bolt and no idea what it is? Measure the outside Ø and type it into Benchsmith → Find → Thread.