# M14 tap drill size

The tap drill for an M14 × 2 metric coarse thread is 12 mm (0.4724 in). It leaves about 77 % thread, the normal range for steel.

## Drill options for M14 × 2

| Drill | Inch | Thread % |
|---|---|---|
| 11.8 mm | 0.4646 | 85 % |
| 11.9 mm | 0.4685 | 81 % |
| 12 mm | 0.4724 | 77 % |
| 12.1 mm | 0.4764 | 73 % |
| 12.2 mm | 0.4803 | 69 % |

## M14 thread data

- Thread: M14 × 2 (coarse)
- Pitch: 2 mm
- Tap drill: 12 mm (0.4724 in)
- Thread engagement: 77 %
- Clearance hole (ISO 273): 15 close, 15.5 normal, 16.5 loose (mm)

## Method

Thread % = 76.98 × (D − drill) / P = 76.98 × 2 / 2 = 77 %. Aim for 65–75 % in steel, 75–85 % in aluminium, brass and plastics.

## FAQ

**What size drill for an M14 × 2 tap?**
Use a 12 mm drill. It leaves about 77 % thread engagement.

**What is 12 mm in inches?**
12 mm is 0.4724 inch.

**What size clearance hole for M14?**
ISO 273 gives 15 mm for a close fit, 15.5 mm normal and 16.5 mm loose.

**How tight should an M14 bolt be?**
About 141 N·m for class 8.8 with dry threads.

Source page: https://machinistcharts.com/tap-drill/m14/
Updated: 2026-10-05
Publisher: MachinistCharts (https://machinistcharts.com)