Tap drill answer
What Size Drill Bit for M8 x 1.25 Tap?
For a M8 x 1.25 tap, a common reference drill is 6.8 mm, which is 0.2677 in or 6.80 mm. Verify the value for material, tap type, and required thread engagement.
M8 x 1.25 tap drill quick answer
Method: Metric values use the visible major-diameter-minus-pitch estimate unless an alternate chart assumption is displayed. Reviewed 2026-07-24.
How to use this M8 x 1.25 value
This page gives a common chart value for hand tapping and general reference work. Use a different value when your drawing specifies a thread class, percent thread, forming tap, pipe thread, thin wall, brittle material, or plated/coated part.
- Start with the listed drill size.
- Confirm the tap type and thread engagement target.
- Test in scrap material when fit matters.
- Use cutting fluid and proper chip clearing for deeper holes.
What size drill bit for M8 x 1.25 tap?
A common starting value for M8 x 1.25 is 6.8 mm. The quick estimate is 8.0 minus 1.25, then rounded to a practical metric drill size.
M8 tap drill size in inches
6.8 mm converts to about 0.2677 in. Use the decimal value to compare with nearby inch drills, then check whether the result is acceptable for the fit.
Is M8 tap drill 6.8 mm or 6.7 mm?
Different charts can round or target different thread percentages. Use the value specified by your drawing, tap maker, or shop standard when the distinction matters.
M8 x 1.25 vs M8 x 1 tap drill size
M8 x 1.25 and M8 x 1 are different pitches. Do not choose a drill from an M8 row unless the pitch also matches.