# #0-80 tap drill size

The tap drill for a #0-80 UNF thread is a 3/64 drill (0.0469 in, 1.19 mm). It leaves about 81 % thread. The closest metric drill is 1.2 mm, which leaves 79 % thread.

## Drill options for #0-80 UNF

| Drill | Inch | Thread % |
|---|---|---|
| 3/64 | 0.0469 | 81 % |
| 1.2 mm | 0.0472 | 79 % |
| 1.3 mm | 0.0512 | 54 % |

## #0-80 thread data

- Thread: #0-80 UNF, 80 TPI
- Major diameter: 0.0600 in (1.52 mm)
- Tap drill: 3/64 = 0.0469 in (1.19 mm)
- Thread engagement: 81 %

## Method

Thread % = TPI × (D − drill) / 0.01299 = 80 × 0.0131 / 0.01299 = 81 %.

## FAQ

**What size drill for a #0-80 tap?**
Use a 3/64 drill (0.0469 in, 1.19 mm). It leaves about 81 % thread.

**Can I use a metric drill for #0-80?**
Yes. A 1.2 mm drill gives about 79 % thread.

Source page: https://machinistcharts.com/tap-drill/0-80/
Updated: 2026-10-05
Publisher: MachinistCharts (https://machinistcharts.com)