M12 × 1.25 Tap Drill Size & Thread Specs
Everything for a M12 × 1.25 fine pitch thread on one page: tap drill (10.8 mm), clearance holes, wrench and hex key sizes, and the nearest inch thread.
SP-TD-01 · M12 × 1.25
M12 × 1.25 specs
SizePlate
M12 × 1.25 · tap with
10.8 mm drill
.4252″
10.8 mm · 74% thread
- Inch drill
- 27/64 · .4219
- Clearance
- 13 / 13.5 mm
- Wrench
- 18 mm
- Cap screw key
- 10 mm
Thread
- Nominal size
- M12 · .4724″
- Pitch
- 1.25 mm · 20.3 TPI
- Series
- fine
- coarse pitch
- M12 × 1.75
- fine pitch
- M12 × 1.5
Drilling
- Tap drill
- 10.8 mm · .4252
- Inch substitute
- 27/64 · .4219
- Close fit
- 13 mm
- Normal fit
- 13.5 mm
- Free fit
- 14.5 mm
Tools
- Hex head (ISO 4017)
- 18 mm
- Hex head (DIN 933)
- 19 mm
- Socket head cap key
- 10 mm
- Button head key
- 8 mm
- Flat head key
- 8 mm
Nearest inch
- Thread
- 1/2-13
- Major diameter
- .5000″
- Threads per inch
- 13
- Tap drill
- 27/64
- Interchangeable
- No
Not interchangeable means the threads look close but won't run together: forcing one into the other strips both.
Drill size by thread percentage
Larger drill, less thread, easier tapping. 75% is the usual target.
| Drill | Decimal | mm | Thread |
|---|---|---|---|
| 10.7 mm | .4213 | 10.7 | 80% |
| 27/64 | .4219 | 10.72 | 79% |
| 10.8 mm | .4252 | 10.8 | 74% |
| 10.9 mm | .4291 | 10.9 | 68% |
| 11 mm | .4331 | 11 | 62% |
| 11.1 mm | .4370 | 11.1 | 55% |
| 7/16 | .4375 | 11.11 | 55% |
| 11.2 mm | .4409 | 11.2 | 49% |
Neighboring sizes
- M10 × 1.0tap 9 mm
- M12 × 1.75tap 10.2 mm
- M12 × 1.5tap 10.5 mm
- M14 × 2.0tap 12 mm
- M14 × 1.5tap 12.5 mm
- M16 × 2.0tap 14 mm
Questions
What does M12 × 1.25 mean?
An ISO metric thread with a 12 mm major diameter and a 1.25 mm pitch (the distance from one thread crest to the next). It’s the fine pitch for M12.
Can I use a 27/64 drill instead?
Usually. 27/64 is .4219″ against .4252″ for the 10.8 mm drill, which changes the thread engagement by a few percent at most.