R1/8 thread: 9.73 mm × 28 TPI
Threads › R1/8
R1/8 is a BSPT taper (R / Rc) thread: 9.73 mm major diameter, 28 TPI (0.907 mm pitch), 55° form. Tap drill 8.4 mm. Taper thread: the Ø changes along the length, measure near the start.
| Standard | BSPT taper (R / Rc) |
|---|---|
| Major diameter | 9.728 mm (0.383″) |
| Pitch | 28 TPI (0.907 mm) |
| Thread angle | 55° |
| Tap drill | 8.4 mm |
Open R1/8 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
- G1/8Ø9.73 mm, 28 TPI
- 3/8-16 UNCØ9.52 mm, 16 TPI
- 3/8-24 UNFØ9.52 mm, 24 TPI
- 3/8 BSWØ9.52 mm, 16 TPI
- 3/8-12 ACMEØ9.52 mm, 12 TPI
- M10Ø10 mm, 1.5 mm pitch
One size up or down
- R1/4Ø13.16 mm (up)
Got a bolt and no idea what it is? Measure the outside Ø and type it into Benchsmith → Find → Thread.