At One Place

M12×1.75 thread

M12×1.75 tap drill
10.2 mm
Clearance hole 13 mm · 18 mm hex

M12×1.75 is a coarse metric thread with a 12 mm (0.472") major diameter and 1.75 mm pitch. Tap it with a 10.2 mm drill; drill 13 mm to pass a bolt through.

The numbers

Designation
M12×1.75
Major diameter
12 mm / 0.472"
Minor diameter
10.106 mm
Pitch
1.75 mm pitch
Tap drill (75% thread)
10.2 mm — 10.2 mm
Clearance hole (close fit)
13 mm / 0.512"
Hex across flats
18 mm

How to measure what you have

  1. Measure across the thread crests with calipers. A used M12×1.75 reads a little under 12 mm — the crests are truncated by the standard, then worn and plated, so anything from about 11.6 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 1.75 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
72–97 N·m
53.1–71.6 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

  • Structural steel connections in metric practice
  • Towbar and tow-bracket mounting bolts
  • Machine feet and levelling mounts
  • Car suspension arms and subframe bolts

Two traps. The tap drill: nominal minus pitch is 10.25 mm, which is not a stocked size, so most charts give 10.2 mm and a few give 10.3 mm — use 10.2 mm in steel and 10.3 mm in something that grabs, such as stainless. The spanner: ISO 4014 and ISO 4032 give 18 mm across flats, while the older DIN 931 and DIN 934 parts take 19 mm.

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
M12×1.5 1.5 mm 10.5 mm 13 mm
M12×1.25 1.25 mm 10.8 mm 13 mm
M12×1 1 mm 11 mm 13 mm

Common questions

What size drill for an M12×1.75 tap?
10.2 mm (10.2 mm), which gives about 75% thread engagement.
What clearance hole for M12×1.75?
13 mm for a close fit — enough to pass the bolt without slop.
What spanner fits M12×1.75?
18 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