3/8-16 UNC thread: 9.52 mm × 16 TPI
Threads › 3/8-16 UNC
3/8-16 UNC is a UNC thread: 9.52 mm major diameter, 16 TPI (1.588 mm pitch), 60° form. Tap drill 8 mm.
| Standard | UNC |
|---|---|
| Major diameter | 9.525 mm (0.375″) |
| Pitch | 16 TPI (1.588 mm) |
| Thread angle | 60° |
| Minor diameter, bolt | 7.58 mm |
| Minor diameter, nut | 7.81 mm |
| Tap drill | 8 mm |
| 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 3/8-16 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
- 3/8-24 UNF24 TPI (1.058 mm pitch)
- 3/8 BSW16 TPI (1.588 mm pitch)
Close in size, won't mate
- 3/8-12 ACMEØ9.52 mm, 12 TPI
- G1/8Ø9.73 mm, 28 TPI
- R1/8Ø9.73 mm, 28 TPI
- M10Ø10 mm, 1.5 mm pitch
- M10×1.25Ø10 mm, 1.25 mm pitch
- M10×1Ø10 mm, 1 mm pitch
One size up or down
- 5/16-18 UNCØ7.94 mm (down)
- 7/16-14 UNCØ11.11 mm (up)
Got a bolt and no idea what it is? Measure the outside Ø and type it into Benchsmith → Find → Thread.