Tap drill answer
What Size Drill Bit for M10 x 1.5 Tap?
For a M10 x 1.5 tap, a common reference drill is 8.5 mm, which is 0.3346 in or 8.50 mm. Verify the value for material, tap type, and required thread engagement.
M10 x 1.5 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 M10 x 1.5 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 M10 x 1.5 tap?
This site shows 8.5 mm as the basic metric estimate for M10 x 1.5 because 10.0 mm minus 1.5 mm equals 8.5 mm. Many 75% thread charts show 8.7 mm, so the right answer depends on which chart assumption you are using.
M10 x 1.5 tap drill size for 75% thread
When a chart targets a practical thread percentage, it may choose a slightly larger drill than the simple formula. A larger drill usually lowers thread percentage and reduces tapping load.
Is M10 x 1.5 tap drill 8.5 mm or 8.7 mm?
Both values appear in common references. The 8.5 mm value is the simple major-minus-pitch estimate. Some 75% thread charts round to 8.7 mm to reduce thread percentage and tapping load. Treat 8.5 mm as a fast rule-of-thumb estimate and compare 8.7 mm when the job needs a published chart or easier tapping.
What should I use for steel or aluminum?
Material changes tapping load and tool life. For critical work, use the tap maker's chart, the drawing, and a test hole instead of assuming one value works across steel, aluminum, stainless, and cast materials.