BSPT Tapered Pipe Thread (R / Rp / Rc) · ISO 7-1 / EN 10226

R 3/4" Thread: Pitch, Tap Drill & Dimensions

R 3/4" is a BSPT Tapered Pipe Thread (R / Rp / Rc) (ISO 7-1 / EN 10226) size, with a major diameter of 26.441 mm, 14 threads per inch (1.814 mm pitch). The tap drill is 24.117 mm.

Profile shape (schematic, not to scale)
R 3/4" thread dimensions
Female Thread DiameterRp 3/4"
Pipe Minor Diameter (mm)20
Pipe Major Diameter (mm)26.441
Tapping Drill Size (mm)24.117
TPI14
Pitch (mm)1.814
Flank angle55°
Taper1:16

Common questions

What size drill do I use to tap R 3/4"?

Use a 24.117 drill. This is the standard tap drill for R 3/4"; for hard materials or deep threads a slightly larger drill reduces tapping torque.

What is the pitch of R 3/4"?

The pitch of R 3/4" is 1.814, meaning the thread advances that distance in one full turn.

Where can I find other BSPT Tapered Pipe Thread (R / Rp / Rc) sizes?

The full BSPT Tapered Pipe Thread (R / Rp / Rc) table, with every size and a live filter, is on its standard page, and the Thread Finder searches all 73 standards at once.

Reference values; computed values use the ISO basic profile. Verify against the current standard before production use.

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