Tr18×4 thread: 18 × 4 mm
Threads › Tr18×4
Tr18×4 is a Trapezoidal (Tr) thread: 18 mm major diameter, 4 mm pitch, 30° form.
| Standard | Trapezoidal (Tr) |
|---|---|
| Major diameter | 18 mm |
| Pitch | 4 mm |
| Thread angle | 30° |
| Minor diameter, bolt | 13.5 mm |
| Minor diameter, nut | 14 mm |
| Tap drill | Not listed. Check your tap maker's chart. |
| Usual class | 7e bolt, 7H nut |
Minor diameters worked out from the basic profile: major Ø − pitch − 0.5 mm (bolt) and major Ø − pitch (nut).
Open Tr18×4 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
- M18Ø18 mm, 2.5 mm pitch
- M18×1.5Ø18 mm, 1.5 mm pitch
- M18×2Ø18 mm, 2 mm pitch
- 3/8-18 NPTØ17.15 mm, 18 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.