1-1/4-7 UNC thread: 31.75 mm × 7 TPI
Threads › 1-1/4-7 UNC
1-1/4-7 UNC is a UNC thread: 31.75 mm major diameter, 7 TPI (3.629 mm pitch), 60° form.
| Standard | UNC |
|---|---|
| Major diameter | 31.75 mm (1.25″) |
| Pitch | 7 TPI (3.629 mm) |
| Thread angle | 60° |
| Minor diameter, bolt | 27.3 mm |
| Minor diameter, nut | 27.82 mm |
| Tap drill | Not listed. Check your tap maker's chart. |
| Usual class | 2A bolt, 2B nut |
Minor diameters worked out from the basic profile: major Ø − 1.22687 × pitch (bolt) and − 1.08253 × pitch (nut).
Open 1-1/4-7 UNC 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.
Same diameter, other pitch
- 1-1/4-12 UNF12 TPI (2.117 mm pitch)
- 1-1/4 BSW7 TPI (3.629 mm pitch)
Close in size, won't mate
- 1-1/4-5 ACMEØ31.75 mm, 5 TPI
- Tr32×6Ø32 mm, 6 mm pitch
One size up or down
- 1-1/8-7 UNCØ28.58 mm (down)
- 1-3/8-6 UNCØ34.92 mm (up)
Got a bolt and no idea what it is? Measure the outside Ø and type it into Benchsmith → Find → Thread.