5/8-18 UNF thread: 15.88 mm × 18 TPI
Threads › 5/8-18 UNF
5/8-18 UNF is a UNF thread: 15.88 mm major diameter, 18 TPI (1.411 mm pitch), 60° form. Tap drill 14.5 mm.
| Standard | UNF |
|---|---|
| Major diameter | 15.875 mm (0.625″) |
| Pitch | 18 TPI (1.411 mm) |
| Thread angle | 60° |
| Minor diameter, bolt | 14.14 mm |
| Minor diameter, nut | 14.35 mm |
| Tap drill | 14.5 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 5/8-18 UNF 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
- 5/8-11 UNC11 TPI (2.309 mm pitch)
- 5/8 BSW11 TPI (2.309 mm pitch)
Close in size, won't mate
- 5/8-8 ACMEØ15.88 mm, 8 TPI
- M16Ø16 mm, 2 mm pitch
- M16×1.5Ø16 mm, 1.5 mm pitch
- Tr16×4Ø16 mm, 4 mm pitch
- G3/8Ø16.66 mm, 19 TPI
- R3/8Ø16.66 mm, 19 TPI
One size up or down
- 9/16-18 UNFØ14.29 mm (down)
- 3/4-16 UNFØ19.05 mm (up)
Got a bolt and no idea what it is? Measure the outside Ø and type it into Benchsmith → Find → Thread.