1-1/2-4 ACME thread: 38.1 mm × 4 TPI
Threads › 1-1/2-4 ACME
1-1/2-4 ACME is an Acme thread: 38.1 mm major diameter, 4 TPI (6.35 mm pitch), 29° form.
| Standard | Acme |
|---|---|
| Major diameter | 38.1 mm (1.5″) |
| Pitch | 4 TPI (6.35 mm) |
| Thread angle | 29° |
| Minor diameter, bolt | 31.24 mm |
| Minor diameter, nut | 31.24 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 1-1/2-4 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
- 1-1/2-6 UNCØ38.1 mm, 6 TPI
- 1-1/2-12 UNFØ38.1 mm, 12 TPI
- 1-1/2 BSWØ38.1 mm, 6 TPI
- M39Ø39 mm, 4 mm pitch
- M39×3Ø39 mm, 3 mm pitch
One size up or down
- 1-1/4-5 ACMEØ31.75 mm (down)
- 1-3/4-4 ACMEØ44.45 mm (up)
Got a bolt and no idea what it is? Measure the outside Ø and type it into Benchsmith → Find → Thread.