ThreadRef

Sizes · Metric (ISO)

Metric coarse

M1.2 × 0.25

Tap drill 0.95 mm for a M1.2 × 0.25 thread — major Ø 1.2 mm, pitch 0.25 mm (101.6 TPI).

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Tap drill
0.95 mm
0.95 mm · ≈77% thread

Profile

Thread form & key diameters

Major Ø 1.2 mmP 0.25 mm60°Minor Ø 0.893 mm · Pitch Ø 1.038 mmM1.2 × 0.25101.6 TPI · 60° form

Dimensions

DesignationM1.2 × 0.25
Major (outside) diameter1.2 mm · 0.0472"
Pitch0.25 mm · 101.6 TPI
Pitch diameter1.038 mm · 0.0409"
Minor diameter (external)0.893 mm · 0.0352"
Minor diameter (internal)0.929 mm · 0.0366"
Recommended tap drill0.95 mm · ≈77% thread
Clearance holeClose 1.3 · Normal 1.4 · Loose 1.5 mm

ISO 273 clearance holes (fine / medium / coarse).

What tap drill do I need for M1.2 × 0.25?

For a M1.2 × 0.25 thread, drill the hole with a 0.95 mm tap drill (0.95 mm — the standard D − P rule) before tapping. That produces roughly 77% thread engagement, the usual target for a strong, tappable hole. The mating bolt has a major diameter of 1.2 mm and a pitch of 0.25 mm (101.6 TPI).

To pass a M1.2 × 0.25 bolt through a part rather than thread it, use a clearance hole: Close 1.3 · Normal 1.4 · Loose 1.5 mm.

All values are generated from the standard thread formulas (ISO 68-1 / ASME B1.1) and published standard tables — not hand-entered. See the full reference.

Nearby sizes

More metric coarse threads

M1 × 0.25Tap 0.75 mmØ 1 mm · pitch 0.25 mmM1.4 × 0.3Tap 1.1 mmØ 1.4 mm · pitch 0.3 mmM1.6 × 0.35Tap 1.25 mmØ 1.6 mm · pitch 0.35 mmM1.8 × 0.35Tap 1.45 mmØ 1.8 mm · pitch 0.35 mmM2 × 0.4Tap 1.6 mmØ 2 mm · pitch 0.4 mmM2.5 × 0.45Tap 2.05 mmØ 2.5 mm · pitch 0.45 mmM3 × 0.5Tap 2.5 mmØ 3 mm · pitch 0.5 mmM3.5 × 0.6Tap 2.9 mmØ 3.5 mm · pitch 0.6 mm