M14×2 thread
M14×2 tap drill
12 mm
Clearance hole 15 mm · 21 mm hex
M14×2 is a coarse metric thread with a 14 mm (0.551") major diameter and 2 mm pitch. Tap it with a 12 mm drill; drill 15 mm to pass a bolt through.
The numbers
- Designation
- M14×2
- Major diameter
- 14 mm / 0.551"
- Minor diameter
- 11.835 mm
- Pitch
- 2 mm pitch
- Tap drill (75% thread)
- 12 mm — 12 mm
- Clearance hole (close fit)
- 15 mm / 0.591"
- Hex across flats
- 21 mm
How to measure what you have
- Measure across the thread crests with calipers. A used M14×2 reads a little under 14 mm — the crests are truncated by the standard, then worn and plated, so anything from about 13.6 mm up is consistent with this size.
- Measure the pitch: put a rule against the threads and count the distance over ten crests, then divide by ten. This one should give 2 mm.
- 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
115–155 N·m
84.8–114.3 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
- Heavy machine base and bearing housing bolts
- Agricultural implement mounting
- Steel fabrication where M12 is too light
ISO 4014 gives 21 mm across flats; DIN 931 gives 22 mm.
Other threads at this diameter
| Thread | Pitch | Tap drill | Clearance |
|---|---|---|---|
| M14×1.5 | 1.5 mm | 12.5 mm | 15 mm |
| M14×1.25 | 1.25 mm | 12.8 mm | 15 mm |
Common questions
- What size drill for an M14×2 tap?
- 12 mm (12 mm), which gives about 75% thread engagement.
- What clearance hole for M14×2?
- 15 mm for a close fit — enough to pass the bolt without slop.
- What spanner fits M14×2?
- 21 mm across the flats on a standard hex head.
Related pages
- M14×1.5 12.5 mm tap drill
- M14×1.25 12.8 mm tap drill
- M12×1.75 10.2 mm tap drill
- M16×2 14 mm tap drill
- M12×1.5 10.5 mm tap drill
- M12×1.25 10.8 mm tap drill
- M12×1 11 mm tap drill
- M16×1.5 14.5 mm tap drill
- M10×1.5 8.5 mm tap drill
- M18×2.5 15.5 mm tap drill
- M10×1.25 8.8 mm tap drill
- M10×1 9 mm tap drill
Sources
- Official vendor product documentation — At One Place
- Typical range compiled from manufacturer specifications — At One Place