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#0-80 tap drill size
Use a 3/64 drill (.0469 in / 1.19 mm) to tap #0-80 UNF. That gives about 81% thread engagement. Closest metric drill: 1.2 mm.
#0-80 thread specifications
| Thread | #0-80 UNF (fine) |
|---|---|
| Major (nominal) diameter | .0600 in / 1.52 mm |
| Threads per inch | 80 (pitch 0.318 mm) |
| Theoretical drill for 75% thread | .0478 in (1.21 mm) |
| Recommended tap drill | 3/64 = .0469 in |
Alternative drills and % of thread
Any of these drills will tap #0-80. Smaller drills give more thread but make tapping harder and raise the risk of breaking the tap, especially in stainless steel and in small sizes. 60–65% thread is common in tough materials. 75% is the general-purpose standard.
Tips for tapping #0-80
- Use cutting fluid, and with a hand tap back off about half a turn every turn or two to break the chip. Aluminium and soft materials are the exception: they tap cleanly with spiral-point taps.
- For blind holes, drill deeper than the thread you need. Allow at least 3–4 pitches beyond the last full thread for a plug tap (0.050" for 80 TPI).
- Thread engagement of 1–1.5 × the diameter (1.5–2.3 mm) is enough for most steel parts. Softer materials need more.