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BreakingChips

ISO metric · coarse

M14 × 2 tap drill size

For general work, OSG suggests 65–70% of full thread. Harder materials and deep holes want less; the calculator sets it from your material.

Cut tap

12.2 mm

0.4803" · 69% thread

Form tap

13 mm

0.5118" · 74% thread

Or 33/64 (0.5156") for 66%

Open M14 × 2 in the calculator

Pick your material for its % of thread, tapping RPM and the rigid-tap code.

Thread dimensions

Major Ø
14.000 mm (0.5512")
Pitch
2 mm
Pitch Ø (basic)
12.701 mm (0.5000")
Minor Ø (internal, basic)
11.835 mm (0.4659")
Thread depth (internal)
1.083 mm (0.0426")

Basic sizes of the 60° form. Tolerance classes (6H) set the limits around them.

Cut tap drills

For a cutting (fluted or spiral) tap. Every standard drill from 50% to 85% thread; suggested rows are in the 65–70% band.

Cut tap drills for M14 × 2
DrillØ inØ mmThread
11.8 mm0.464611.8085%
11.9 mm0.468511.9081%
15/320.468811.9181%
12 mm0.472412.0077%
12.1 mm0.476412.1073%
12.2 mmsuggested0.480312.2069%
12.3 mmsuggested0.484312.3065%
31/64suggested0.484412.3065%
12.4 mm0.488212.4062%
12.5 mm0.492112.5058%
12.6 mm0.496112.6054%
1/20.500012.7050%
12.7 mm0.500012.7050%

Form tap drills

A form (roll) tap displaces metal instead of cutting it, so it needs a bigger hole. Every standard drill from 50% to 85% thread; suggested rows are in the 65–70% band.

Form tap drills for M14 × 2
DrillØ inØ mmThread
12.9 mm0.507912.9081%
13 mm0.511813.0074%
33/64suggested0.515613.1066%

3-wire measurement

Best wire size
1.155 mm (0.0455")
Over wires, at basic pitch Ø
14.433 mm (0.5682")

For the external thread (the screw). The best wire touches the flanks at the pitch diameter.

Sources