M4×0.7 thread

M4×0.7 is a coarse metric thread with a 4 mm (0.157") major diameter and 0.7 mm pitch. Tap it with a 3.3 mm drill; drill 4.3 mm to pass a bolt through.

The numbers

Designation

M4×0.7

Major diameter

4 mm / 0.157"

Minor diameter

3.242 mm

Pitch

0.7 mm pitch

Tap drill (75% thread)

3.3 mm — 3.3 mm

Clearance hole (close fit)

4.3 mm / 0.169"

Hex across flats

7 mm

How to measure what you have

1. Measure across the thread crests with calipers. A used M4×0.7 reads a little under 4 mm — the crests are truncated by the standard, then worn and plated, so anything from about 3.6 mm up is consistent with this size.
2. Measure the pitch: put a rule against the threads and count the distance over ten crests, then divide by ten. This one should give 0.7 mm.
3. A thread pitch gauge settles it in seconds and costs very little. Guessing between a coarse and a fine thread of the same diameter is the usual way a thread gets stripped.

Tightening torque

Plain steel property class 8.8 or SAE grade 5, dry threads, tightened to about 65% of yield. Lubricated threads reach the same preload at 20-30% less torque. Where the manufacturer publishes a figure — spark plugs, wheel nuts, cylinder heads — use theirs.

Where this size turns up

• VESA 75×75 and 100×100 monitor mounts
• Enclosure lids and small equipment covers
• Ikea and flat-pack fittings
• Panel-mount switches and connectors