Tap drill answer
What Size Drill Bit for #10-24 UNC Tap?
For a #10-24 UNC tap, a common reference drill is #25, which is 0.1495 in or 3.80 mm. Verify the value for material, tap type, and required thread engagement.
#10-24 UNC tap drill quick answer
Method: Named UNC and UNF drill sizes are maintained as common cutting-tap reference values and checked against manufacturer ranges. Reviewed 2026-07-24.
How to use this #10-24 UNC 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 drill bit size for 10-24 tap?
A common chart value for a #10-24 UNC tap is a #25 drill, which is 0.1495 in or about 3.80 mm. This is the coarse #10 machine-screw thread.
10-24 tap drill size vs 10-32
#10-24 commonly uses #25. #10-32 commonly uses #21. Read the threads per inch before picking the drill from a #10 row.
What is #25 drill size in mm?
A #25 drill is 0.1495 in, which converts to about 3.80 mm. Use the decimal column when comparing it with the nearest metric bit.
When should I adjust the 10-24 tap drill?
Hard material, blind holes, forming taps, or specified thread percentage can require a different hole. The chart value is a starting point, not a substitute for the drawing.