# M10 tap drill size

URL: https://www.clove3d.com/tools/tap-drill/m10/

Tap drill for M10 × 1.5: 8.5 mm (0.3346 in / 8.50 mm), about 77% thread.

## Thread specs

- Series: ISO metric coarse
- Major diameter: 10.00 mm
- Pitch: 1.5 mm
- Basic minor diameter: 8.38 mm

## Every drill that works (50-85% thread)

| Drill | % thread | in | mm | Good for |
|---|---|---|---|---|
| 9.0 mm | 51% | 0.3543 | 9.00 | deep holes only |
| 8.9 mm | 56% | 0.3504 | 8.90 | deep holes only |
| S | 60% | 0.3480 | 8.84 | deep holes only |
| 8.8 mm | 62% | 0.3465 | 8.80 | hard or tough metals |
| 11/32" | 65% | 0.3438 | 8.73 | hard or tough metals |
| 8.7 mm | 67% | 0.3425 | 8.70 | hard or tough metals |
| R | 71% | 0.3390 | 8.61 | general use |
| 8.6 mm | 72% | 0.3386 | 8.60 | general use |
| 8.5 mm (standard) | 77% | 0.3346 | 8.50 | general use |
| Q | 80% | 0.3320 | 8.43 | more torque, more broken taps |
| 8.4 mm | 82% | 0.3307 | 8.40 | more torque, more broken taps |

## Clearance hole

- Close (fine): 10.5 mm (0.4134 in / 10.50 mm)
- Normal (medium): 11.0 mm (0.4331 in / 11.00 mm)
- Loose (coarse): 12.0 mm (0.4724 in / 12.00 mm)

## Counterbore (socket head cap screw)

- NBK: diameter 17.50 mm, depth 10.80 mm
- AMES: diameter 17.25 mm, depth 10.00 mm

Countersink (flat head socket screw): 90 degrees to 22.40 mm across for a flush head.

## Thread repair (Helicoil / STI drill)

- MISUMI: 10.3 mm (0.4055 in / 10.30 mm)

## FAQ

Q: What size drill do I use for an M10 tap?
A: Use a 8.5 mm (8.50 mm / 0.3346 in) drill. It leaves about 77% thread, the standard for general-purpose tapping.

Q: What inch drill can I use for an M10 tap?
A: Q (8.43 mm / 0.3320 in) is the closest, giving about 80% thread. Anything from about 65% to 80% thread taps well in most materials.

Q: What size clearance hole for an M10 screw?
A: 10.5 mm (10.50 mm) for a close fit, 11.0 mm (11.00 mm) for a normal fit.

Q: What is the inch equivalent of M10?
A: 3/8-16 is the closest size (9.52 mm vs 10.00 mm major diameter). The pitches differ, so the screws and tapped holes are not interchangeable.

## Sources

- Engineers Edge: metric ISO tap drill chart: https://www.engineersedge.com/manufacturing/metric-iso-tap-drill-chart.htm
- Penn MEDesign: tap drill chart: https://medesign.seas.upenn.edu/index.php/Guides.TapDrillChart
- Albany County Fasteners: clearance hole chart (PDF): https://www.albanycountyfasteners.com/media/6b/b8/g0/1764944339/clearance-hole-chart.pdf
- AMES: metric clearance hole chart (ASME B18.2.8): https://amesweb.info/Screws/Metric-Clearance-Hole-Chart.aspx
- NBK: dimensions of holes for hexagon socket head cap screws: https://alb02.internal.nbk1560.com/en/resources/other/article/technical-22-dimensions-of-holes-for-hexagon-socket-cap-screws
- AMES: counterbore hole dimensions, metric (Machinery's Handbook): https://amesweb.info/Screws/Metric-Counterbore-Hole-Dimensions-Chart.aspx
- Global Fastener: ISO 10642 hexagon socket countersunk head screws: https://www.globalfastener.com/standards/detailn_182.html
- Eugene Fastener: flat head socket screw countersink guide: https://www.eugenefast.com/Home/Page/resources/flat-head-socket-screw-countersink-guide
- SC Fastening: flat head socket cap screw spec, ASME B18.3 (PDF): https://scfastening.com/wp-content/uploads/2017/06/flatsocketspec.pdf
- MISUMI: Helicoil tap and drill size chart: https://blog.misumiusa.com/helicoil-tap-and-drill-size-chart/