#6-32 Tap Drill Size & Thread Specs
Everything for a #6-32 UNC thread on one page: tap drill (#36), clearance holes, wrench and hex key sizes, and the nearest metric thread.
SP-TD-01 · #6-32
#6-32 specs
SizePlate
#6-32 UNC · tap with
#36 drill
.1065″
2.71 mm · 78% thread
- Metric drill
- 2.7 mm · .1063
- Clearance
- #27 / #25
- Wrench
- 5/16″
- Cap screw key
- 7/64″
Thread
- Nominal size
- #6 · 3.51 mm
- Major diameter
- .1380″
- Threads per inch
- 32
- Pitch
- .0312″ · 0.794 mm
- Series
- UNC (coarse)
- UNF version
- #6-40
Drilling
- Tap drill (75%)
- #36 · .1065
- Metric substitute
- 2.7 mm · .1063
- Tap drill (≈50%)
- #32 · .1160
- Close fit
- #27 · .1440
- Free fit
- #25 · .1495
Tools
- Hex bolt wrench
- —
- Hex nut wrench
- 5/16″
- Socket head cap key
- 7/64″
- Button head key
- 5/64″
- Flat head key
- 5/64″
Nearest metric
- Thread
- M4 × 0.7
- Major diameter
- 4 mm
- Pitch
- 0.7 mm
- Tap drill
- 3.3 mm
- Interchangeable
- No
Not interchangeable means the threads look close but won't run together: forcing one into the other strips both.
Drill size by thread percentage
Larger drill, less thread, easier tapping. 75% is the usual target.
| Drill | Decimal | mm | Thread |
|---|---|---|---|
| #37 | .1040 | 2.64 | 84% |
| 2.65 mm | .1043 | 2.65 | 83% |
| 2.7 mm | .1063 | 2.7 | 78% |
| #36 | .1065 | 2.71 | 78% |
| 7/64 | .1094 | 2.78 | 70% |
| #35 | .1100 | 2.79 | 69% |
| 2.8 mm | .1102 | 2.8 | 68% |
| #34 | .1110 | 2.82 | 67% |
| #33 | .1130 | 2.87 | 62% |
| 2.9 mm | .1142 | 2.9 | 59% |
| #32 | .1160 | 2.95 | 54% |
| 3 mm | .1181 | 3 | 49% |
Neighboring sizes
Questions
What does #6-32 mean?
A #6 nominal diameter with 32 threads per inch. It’s the coarse (UNC) thread for that size; the fine version is #6-40.
Can I use a 2.7 mm drill instead of #36?
Usually. 2.7 mm is .1063″ against .1065″ for #36, which changes the thread engagement by a few percent at most. The thread-percentage table above shows exactly how much thread each nearby drill leaves.