1/2-13 UNC thread: 12.7 mm × 13 TPI
Threads › 1/2-13 UNC
1/2-13 UNC is a UNC thread: 12.7 mm major diameter, 13 TPI (1.954 mm pitch), 60° form. Tap drill 10.8 mm.
| Standard | UNC |
|---|---|
| Major diameter | 12.7 mm (0.5″) |
| Pitch | 13 TPI (1.954 mm) |
| Thread angle | 60° |
| Minor diameter, bolt | 10.3 mm |
| Minor diameter, nut | 10.58 mm |
| Tap drill | 10.8 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 1/2-13 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
- 1/2-20 UNF20 TPI (1.27 mm pitch)
- 1/2 BSW12 TPI (2.117 mm pitch)
Close in size, won't mate
- 1/2-10 ACMEØ12.7 mm, 10 TPI
- G1/4Ø13.16 mm, 19 TPI
- R1/4Ø13.16 mm, 19 TPI
- M12Ø12 mm, 1.75 mm pitch
- M12×1.5Ø12 mm, 1.5 mm pitch
- M12×1.25Ø12 mm, 1.25 mm pitch
One size up or down
- 7/16-14 UNCØ11.11 mm (down)
- 9/16-12 UNCØ14.29 mm (up)
Got a bolt and no idea what it is? Measure the outside Ø and type it into Benchsmith → Find → Thread.