6-32 tap drill size
Drill a #36 hole (0.1065" / 2.71 mm) for a 6-32 UNC tap. That leaves about 78% thread, the standard for general-purpose tapping.
6-32 tap drill: #36 (0.1065 in / 2.71 mm), 78% thread6-32 thread specs
| Series | Unified coarse (UNC) |
|---|---|
| Major diameter | 0.1380" (3.51 mm) |
| Pitch | 32 TPI (0.79 mm) |
| Basic minor diameter | 0.1042" (2.65 mm) |
| Common internal class | 2B |
Every drill that works for 6-32
Drills from all four sets that give 50–85% thread, largest first. Lower percentages tap easier; see how much thread you need.
| Drill | Thread | in | mm | Set | Good for |
|---|---|---|---|---|---|
| 2.95 mm | 54% | 0.1161 | 2.95 | Metric | deep holes only |
| #32 | 54% | 0.1160 | 2.95 | Number | deep holes only |
| 2.9 mm | 59% | 0.1142 | 2.90 | Metric | deep holes only |
| #33 | 62% | 0.1130 | 2.87 | Number | hard or tough metals |
| 2.85 mm | 64% | 0.1122 | 2.85 | Metric | hard or tough metals |
| #34 | 67% | 0.1110 | 2.82 | Number | hard or tough metals |
| 2.8 mm | 68% | 0.1102 | 2.80 | Metric | hard or tough metals |
| #35 | 69% | 0.1100 | 2.79 | Number | hard or tough metals |
| 7/64" | 71% | 0.1094 | 2.78 | Fractional | general use |
| 2.75 mm | 73% | 0.1083 | 2.75 | Metric | general use |
| #36standard | 78% | 0.1065 | 2.71 | Number | general use |
| 2.7 mm | 78% | 0.1063 | 2.70 | Metric | general use |
| 2.65 mm | 83% | 0.1043 | 2.65 | Metric | more torque, more broken taps |
| #37 | 84% | 0.1040 | 2.64 | Number | more torque, more broken taps |
6-32 clearance hole
The hole a 6-32 screw passes through. Close fit locates parts; free fit is forgiving.
| Fit | Drill | in | mm |
|---|---|---|---|
| Close fit | #27 | 0.1440 | 3.66 |
| Free fit | #25 | 0.1495 | 3.80 |
6-32 counterbore and countersink
For a socket head cap screw to sit flush, and for a flat head socket screw.
| Socket head counterbore | Diameter | Depth |
|---|---|---|
| AMES | 9/32" 0.2813" | 0.1380" |
Flat head socket screw: countersink at 82° (inch screws, ASME B18.3) to 0.3070" (7.80 mm) across for a flush head. Metric flat heads use 90°, so don't mix countersinks.
6-32 heat-set insert hole
Hole to model for a brass heat-set insert in a 3D print. Brands size their knurl differently, so use your brand’s number.
| Brand | Hole |
|---|---|
| Generic (Albany County) | 0.1660" |
6-32 holes in a 3D print
Printed holes usually come out undersize. Model the hole at the drill size plus what your printer loses, then tap or drill to size. Why printed holes shrink.
Print a test hole, measure it with calipers, enter the difference. 0 models the nominal size.
6-32 thread repair (Helicoil)
Stripped 6-32 thread? Drill out with the STI drill, tap with a 6-32 UNC STI tap, and fit a wire thread insert. The drill in your repair kit’s instructions wins over any chart.
| Chart | STI drill | in | mm |
|---|---|---|---|
| AMES | #25 | 0.1495 | 3.80 |
| MISUMI | #25 | 0.1495 | 3.80 |
Related sizes
Frequently asked questions
What size drill do I use for a 6-32 tap?
What metric drill can I use for a 6-32 tap?
What size clearance hole for a 6-32 screw?
What hole size for a 6-32 heat-set insert?
Sources
- Engineers Edge: machinist screw thread tap drill chart (ANSI) checked 2026-10-19
- Penn MEDesign: tap drill chart checked 2026-10-19
- Fractory: imperial clearance hole sizes checked 2026-10-19
- AMES: counterbore hole dimensions, inch (Machinery's Handbook) checked 2026-10-19
- SC Fastening: flat head socket cap screw spec, ASME B18.3 (PDF) checked 2026-10-19
- Eugene Fastener: flat head socket screw countersink guide checked 2026-10-19
- Albany County Fasteners: heat-set insert specs (PDF) checked 2026-10-19
- AMES: Helicoil tap sizes (STI) checked 2026-10-19
- MISUMI: Helicoil tap and drill size chart checked 2026-10-19
Spotted a wrong number? Email contact@clove3d.com and it gets fixed.
% thread = (major − drill) ÷ (1.299 × pitch) × 100. The standard drill comes from published charts and is checked against this formula on every build.