What drill for a M12×1.75 roll (form) tap?

About 11.23 mm; the nearest standard drill is 11.25 mm. Check your tap maker's table.

What drill for a M12×1.75 Helicoil?

Drill 12.8mm (12.80 mm), then tap with the M12×1.75 STI tap.

M12×1.75 tap drill size

Use a 10.2mm drill (10.20 mm) for a M12×1.75 cutting tap at 75% thread.

Drills for M12×1.75 (Metric)
Tap type	Drill	Decimal (mm)
Cutting tap, 75% thread	10.2mm	10.20
Cutting tap, 50% thread (hard material)	10.9mm	10.90
Roll / form tap, 65% thread	11.25 mm	11.25
Helicoil / STI insert (M12×1.75×1D)	12.8mm	12.80

Pitch: 1.75 mm
Major Ø: 12.00
Pitch Ø: 10.86
Minor Ø: 10.11

M12×1.75 tapping speeds and feeds

Feed = pitch (1.75 mm per rev). Starting points for a general-purpose HSS cut tap:

Aluminum 6061 / 7075: 570 RPM · 998 mm/min
Free-machining / mild steel: 160 RPM · 280 mm/min
304 / 316 stainless: 80 RPM · 140 mm/min

M12×1.75 tap speeds and feeds: all materials, form taps and G84 code · 10.2mm drill size and speeds

Open the tap drill calculator Roll tap chart Helicoil chart

Common questions

What size drill for a M12×1.75 tap?: Use a 10.2mm drill (10.20 mm) for a M12×1.75 cutting tap at 75% thread.
What drill for a M12×1.75 roll (form) tap?: About 11.23 mm; the nearest standard drill is 11.25 mm. Check your tap maker's table.
What drill for a M12×1.75 Helicoil?: Drill 12.8mm (12.80 mm), then tap with the M12×1.75 STI tap.

Drill sizes from Machinery's Handbook and ASME B1.1/B1.13M; roll tap sizes from the form-tap formula. Tap and insert makers' tables are authoritative.

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