M8 × 1.0 Tap Drill Size & Thread Specs
Everything for a M8 × 1.0 fine pitch thread on one page: tap drill (7 mm), clearance holes, wrench and hex key sizes, and the nearest inch thread.
SP-TD-01 · M8 × 1.0
M8 × 1.0 specs
SizePlate
M8 × 1.0 · tap with
7 mm drill
.2756″
7 mm · 77% thread
- Inch drill
- J · .2770
- Clearance
- 8.4 / 9 mm
- Wrench
- 13 mm
- Cap screw key
- 6 mm
Thread
- Nominal size
- M8 · .3150″
- Pitch
- 1 mm · 25.4 TPI
- Series
- fine
- coarse pitch
- M8 × 1.25
Drilling
- Tap drill
- 7 mm · .2756
- Inch substitute
- J · .2770
- Close fit
- 8.4 mm
- Normal fit
- 9 mm
- Free fit
- 10 mm
Tools
- Hex head (ISO 4017)
- 13 mm
- Hex head (DIN 933)
- 13 mm
- Socket head cap key
- 6 mm
- Button head key
- 5 mm
- Flat head key
- 5 mm
Nearest inch
- Thread
- 5/16-18
- Major diameter
- .3125″
- Threads per inch
- 18
- Tap drill
- F
- 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 |
|---|---|---|---|
| 6.9 mm | .2717 | 6.9 | 85% |
| I | .2720 | 6.91 | 84% |
| 7 mm | .2756 | 7 | 77% |
| J | .2770 | 7.04 | 74% |
| 7.1 mm | .2795 | 7.1 | 69% |
| K | .2810 | 7.14 | 66% |
| 9/32 | .2813 | 7.15 | 66% |
| 7.2 mm | .2835 | 7.2 | 62% |
| 7.3 mm | .2874 | 7.3 | 54% |
| L | .2900 | 7.37 | 49% |
| 7.4 mm | .2913 | 7.4 | 46% |
Neighboring sizes
- M6 × 1.0tap 5 mm
- M6 × 0.75tap 5.2 mm
- M8 × 1.25tap 6.8 mm
- M10 × 1.5tap 8.5 mm
- M10 × 1.25tap 8.8 mm
- M10 × 1.0tap 9 mm
Questions
What does M8 × 1.0 mean?
An ISO metric thread with a 8 mm major diameter and a 1 mm pitch (the distance from one thread crest to the next). It’s the fine pitch for M8.
Can I use a J drill instead?
Usually. J is .2770″ against .2756″ for the 7 mm drill, which changes the thread engagement by a few percent at most.