# #5-44 tap drill size

The tap drill for a #5-44 UNF thread is a #37 drill (0.1040 in, 2.64 mm). It leaves about 71 % thread. The closest metric drill is 2.6 mm, which leaves 77 % thread.

## Drill options for #5-44 UNF

| Drill | Inch | Thread % |
|---|---|---|
| #37 | 0.1040 | 71 % |
| 2.5 mm | 0.0984 | 90 % |
| 2.6 mm | 0.1024 | 77 % |
| 2.7 mm | 0.1063 | 63 % |

## #5-44 thread data

- Thread: #5-44 UNF, 44 TPI
- Major diameter: 0.1250 in (3.17 mm)
- Tap drill: #37 = 0.1040 in (2.64 mm)
- Thread engagement: 71 %

## Method

Thread % = TPI × (D − drill) / 0.01299 = 44 × 0.0210 / 0.01299 = 71 %.

## FAQ

**What size drill for a #5-44 tap?**
Use a #37 drill (0.1040 in, 2.64 mm). It leaves about 71 % thread.

**Can I use a metric drill for #5-44?**
Yes. A 2.6 mm drill gives about 77 % thread.

Source page: https://machinistcharts.com/tap-drill/5-44/
Updated: 2026-10-05
Publisher: MachinistCharts (https://machinistcharts.com)