# M22 tap drill size

The tap drill for an M22 × 2.5 metric coarse thread is 19.5 mm (0.7677 in). It leaves about 77 % thread, the normal range for steel.

## Drill options for M22 × 2.5

| Drill | Inch | Thread % |
|---|---|---|
| 19.3 mm | 0.7598 | 83 % |
| 19.4 mm | 0.7638 | 80 % |
| 19.5 mm | 0.7677 | 77 % |
| 19.6 mm | 0.7717 | 74 % |
| 19.7 mm | 0.7756 | 71 % |

## M22 thread data

- Thread: M22 × 2.5 (coarse)
- Pitch: 2.5 mm
- Tap drill: 19.5 mm (0.7677 in)
- Thread engagement: 77 %
- Clearance hole (ISO 273): 23 close, 24 normal, 26 loose (mm)

## Method

Thread % = 76.98 × (D − drill) / P = 76.98 × 2.5 / 2.5 = 77 %. Aim for 65–75 % in steel, 75–85 % in aluminium, brass and plastics.

## FAQ

**What size drill for an M22 × 2.5 tap?**
Use a 19.5 mm drill. It leaves about 77 % thread engagement.

**What is 19.5 mm in inches?**
19.5 mm is 0.7677 inch.

**What size clearance hole for M22?**
ISO 273 gives 23 mm for a close fit, 24 mm normal and 26 mm loose.

**How tight should an M22 bolt be?**
About 601 N·m for class 8.8 with dry threads.

Source page: https://machinistcharts.com/tap-drill/m22/
Updated: 2026-10-05
Publisher: MachinistCharts (https://machinistcharts.com)