R1-1/4 thread: 41.91 mm × 11 TPI
Threads › R1-1/4
R1-1/4 is a BSPT taper (R / Rc) thread: 41.91 mm major diameter, 11 TPI (2.309 mm pitch), 55° form. Tap drill 38.5 mm. Taper thread: the Ø changes along the length, measure near the start.
| Standard | BSPT taper (R / Rc) |
|---|---|
| Major diameter | 41.91 mm (1.65″) |
| Pitch | 11 TPI (2.309 mm) |
| Thread angle | 55° |
| Tap drill | 38.5 mm |
Open R1-1/4 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
- G1-1/4Ø41.91 mm, 11 TPI
- M42Ø42 mm, 4.5 mm pitch
- M42×3Ø42 mm, 3 mm pitch
- M42×2Ø42 mm, 2 mm pitch
- 1-1/4-11.5 NPTØ42.16 mm, 11.5 TPI
One size up or down
Got a bolt and no idea what it is? Measure the outside Ø and type it into Benchsmith → Find → Thread.