ISO Metric Coarse Thread · DIN 13-1 / ISO 261

M30 Thread: Pitch, Tap Drill & Dimensions

M30 is an ISO metric coarse thread with a 3.5 mm pitch. The tap drill is 26.5 mm, and the internal minor diameter D1 is 26.211 mm.

Profile shape (schematic, not to scale)
M30 thread dimensions
Nominal (major) diameter30 mm
Pitch3.5 mm (coarse)
Tap drill (D − P)26.5 mm
Pitch diameter d2 / D227.727 mm
Minor diameter, external d325.706 mm
Minor diameter, internal D126.211 mm
Thread depth, external h32.147 mm
Flank angle60°
Clearance hole (fine / medium / coarse)31 / 33 / 35 mm
Hex spanner size (ISO 4032)46 mm
Socket cap screw hex key (ISO 4762)22 mm

Common questions

What size drill do I use to tap M30?

Use a 26.5 mm drill. This is the standard tap drill for M30; for hard materials or deep threads a slightly larger drill reduces tapping torque.

What is the pitch of M30?

The pitch of M30 is 3.5 mm (coarse), meaning the thread advances that distance in one full turn.

Where can I find other ISO Metric Coarse Thread sizes?

The full ISO Metric Coarse Thread 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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