M4 × 0.5 Tap Drill Size & Thread Specs
Everything for a M4 × 0.5 fine pitch thread on one page: tap drill (3.5 mm), clearance holes, wrench and hex key sizes, and the nearest inch thread.
SP-TD-01 · M4 × 0.5
M4 × 0.5 specs
SizePlate
M4 × 0.5 · tap with
3.5 mm drill
.1378″
3.5 mm · 77% thread
- Inch drill
- #29 · .1360
- Clearance
- 4.3 / 4.5 mm
- Wrench
- 7 mm
- Cap screw key
- 3 mm
Thread
- Nominal size
- M4 · .1575″
- Pitch
- 0.5 mm · 50.8 TPI
- Series
- fine
- coarse pitch
- M4 × 0.7
Drilling
- Tap drill
- 3.5 mm · .1378
- Inch substitute
- #29 · .1360
- Close fit
- 4.3 mm
- Normal fit
- 4.5 mm
- Free fit
- 4.8 mm
Tools
- Hex head (ISO 4017)
- 7 mm
- Hex head (DIN 933)
- 7 mm
- Socket head cap key
- 3 mm
- Button head key
- 2.5 mm
- Flat head key
- 2.5 mm
Nearest inch
- Thread
- #8-32
- Major diameter
- .1640″
- Threads per inch
- 32
- Tap drill
- #29
- 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 |
|---|---|---|---|
| #29 | .1360 | 3.45 | 84% |
| 3.5 mm | .1378 | 3.5 | 77% |
| #28 | .1405 | 3.57 | 66% |
| 9/64 | .1406 | 3.57 | 66% |
| 3.6 mm | .1417 | 3.6 | 62% |
| #27 | .1440 | 3.66 | 53% |
| 3.7 mm | .1457 | 3.7 | 46% |
Neighboring sizes
- M3 × 0.5tap 2.5 mm
- M3 × 0.35tap 2.65 mm
- M4 × 0.7tap 3.3 mm
- M5 × 0.8tap 4.2 mm
- M5 × 0.5tap 4.5 mm
- M6 × 1.0tap 5 mm
Questions
What does M4 × 0.5 mean?
An ISO metric thread with a 4 mm major diameter and a 0.5 mm pitch (the distance from one thread crest to the next). It’s the fine pitch for M4.
Can I use a #29 drill instead?
Usually. #29 is .1360″ against .1378″ for the 3.5 mm drill, which changes the thread engagement by a few percent at most.