At One Place

M10×1.5 thread

M10×1.5 tap drill
8.5 mm
Clearance hole 10.5 mm · 16 mm hex

M10×1.5 is a coarse metric thread with a 10 mm (0.394") major diameter and 1.5 mm pitch. Tap it with a 8.5 mm drill; drill 10.5 mm to pass a bolt through.

The numbers

Designation
M10×1.5
Major diameter
10 mm / 0.394"
Minor diameter
8.376 mm
Pitch
1.5 mm pitch
Tap drill (75% thread)
8.5 mm — 8.5 mm
Clearance hole (close fit)
10.5 mm / 0.413"
Hex across flats
16 mm

How to measure what you have

  1. Measure across the thread crests with calipers. A used M10×1.5 reads a little under 10 mm — the crests are truncated by the standard, then worn and plated, so anything from about 9.6 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 1.5 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

Typical torque
41–56 N·m
30.2–41.3 lb·ft

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

  • Brake caliper and suspension bolts on cars
  • Motorcycle axle pinch bolts
  • Engine and gearbox mounting bolts
  • Scaffolding and staging fittings

ISO 4014 and ISO 4032 give 16 mm across flats; the older DIN 931 and DIN 934 parts you will still find in a drawer take a 17 mm spanner.

Other threads at this diameter

Same diameter, different pitch. Forcing the wrong one strips the thread in a turn or two.
Thread Pitch Tap drill Clearance
M10×1.25 1.25 mm 8.8 mm 10.5 mm
M10×1 1 mm 9 mm 10.5 mm

Common questions

What size drill for an M10×1.5 tap?
8.5 mm (8.5 mm), which gives about 75% thread engagement.
What clearance hole for M10×1.5?
10.5 mm for a close fit — enough to pass the bolt without slop.
What spanner fits M10×1.5?
16 mm across the flats on a standard hex head.

Related pages

Sources

  1. Official vendor product documentation — At One Place
  2. Typical range compiled from manufacturer specifications — At One Place

How these figures are compiled and checked