# #6-32 tap drill size

The tap drill for a #6-32 UNC thread is a #36 drill (0.1065 in, 2.71 mm). It leaves about 78 % thread. The closest metric drill is 2.7 mm, which leaves 78 % thread.

## Drill options for #6-32 UNC

| Drill | Inch | Thread % |
|---|---|---|
| #36 | 0.1065 | 78 % |
| 2.6 mm | 0.1024 | 88 % |
| 2.7 mm | 0.1063 | 78 % |
| 2.8 mm | 0.1102 | 68 % |

## #6-32 thread data

- Thread: #6-32 UNC, 32 TPI
- Major diameter: 0.1380 in (3.51 mm)
- Tap drill: #36 = 0.1065 in (2.71 mm)
- Thread engagement: 78 %

## Method

Thread % = TPI × (D − drill) / 0.01299 = 32 × 0.0315 / 0.01299 = 78 %.

## FAQ

**What size drill for a #6-32 tap?**
Use a #36 drill (0.1065 in, 2.71 mm). It leaves about 78 % thread.

**Can I use a metric drill for #6-32?**
Yes. A 2.7 mm drill gives about 78 % thread.

Source page: https://machinistcharts.com/tap-drill/6-32/
Updated: 2026-10-05
Publisher: MachinistCharts (https://machinistcharts.com)