Tap drill answer
What Size Drill Bit for #8-32 UNC Tap?
For a #8-32 UNC tap, a common reference drill is #29, which is 0.1360 in or 3.45 mm. Verify the value for material, tap type, and required thread engagement.
#8-32 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 #8-32 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 8-32 tap?
A common chart value for a #8-32 UNC tap is a #29 drill, which is 0.1360 in or about 3.45 mm. It is a frequent lookup for small machine screws and light fixtures.
8-32 tap drill size in inches and mm
Use 0.1360 in as the decimal reference and 3.45 mm as the conversion. If a kit lists only nearby metric sizes, compare the actual drill diameter instead of relying on the label alone.
Can I use a larger drill for 8-32?
A slightly larger drill lowers thread engagement and can reduce tapping load, but it also leaves less thread. Use the drawing or tooling chart when fit or strength matters.
8-32 tap drill for thin material
Thin material gives fewer engaged threads, so avoid casually oversizing the hole. Test a sample when the screw needs to hold load or repeated assembly.