5/8-11 tap drill size
Drill a 17/32" hole (0.5313" / 13.49 mm) for a 5/8-11 UNC tap. That leaves about 79% thread, the standard for general-purpose tapping.
5/8-11 tap drill: 17/32" (0.5313 in / 13.49 mm), 79% thread5/8-11 thread specs
| Series | Unified coarse (UNC) |
|---|---|
| Major diameter | 0.6250" (15.88 mm) |
| Pitch | 11 TPI (2.31 mm) |
| Basic minor diameter | 0.5266" (13.38 mm) |
| Common internal class | 2B |
Every drill that works for 5/8-11
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 |
|---|---|---|---|---|---|
| 9/16" | 53% | 0.5625 | 14.29 | Fractional | deep holes only |
| 14.0 mm | 63% | 0.5512 | 14.00 | Metric | hard or tough metals |
| 35/64" | 66% | 0.5469 | 13.89 | Fractional | hard or tough metals |
| 13.5 mm | 79% | 0.5315 | 13.50 | Metric | general use |
| 17/32"standard | 79% | 0.5313 | 13.49 | Fractional | general use |
5/8-11 clearance hole
The hole a 5/8-11 screw passes through. Close fit locates parts; free fit is forgiving.
| Fit | Drill | in | mm |
|---|---|---|---|
| Close fit | 41/64" | 0.6406 | 16.27 |
| Free fit | 21/32" | 0.6563 | 16.67 |
5/8-11 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 | 1" 1.0000" | 0.6250" |
Flat head socket screw: countersink at 82° (inch screws, ASME B18.3) to 1.1880" (30.18 mm) across for a flush head. Metric flat heads use 90°, so don't mix countersinks.
5/8-11 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.
5/8-11 thread repair (Helicoil)
Stripped 5/8-11 thread? Drill out with the STI drill, tap with a 5/8-11 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 | 21/32" | 0.6563 | 16.67 |
| MISUMI | 21/32" | 0.6563 | 16.67 |
Related sizes
Frequently asked questions
What size drill do I use for a 5/8-11 tap?
What metric drill can I use for a 5/8-11 tap?
What size clearance hole for a 5/8-11 screw?
What is the metric equivalent of 5/8-11?
Sources
- Engineers Edge: machinist screw thread tap drill chart (ANSI) checked 2026-10-19
- ETSU: tap, drill & clearance chart checked 2026-10-19
- Albany County Fasteners: clearance hole chart (PDF) 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
- 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.