M2.5 × 0.45 Tap Drill Size & Thread Specs
Everything for a M2.5 × 0.45 coarse pitch thread on one page: tap drill (2.05 mm), clearance holes, wrench and hex key sizes, and the nearest inch thread.
SP-TD-01 · M2.5 × 0.45
M2.5 × 0.45 specs
SizePlate
M2.5 × 0.45 · tap with
2.05 mm drill
.0807″
2.05 mm · 77% thread
- Inch drill
- #46 · .0810
- Clearance
- 2.7 / 2.9 mm
Thread
- Nominal size
- M2.5 · .0984″
- Pitch
- 0.45 mm · 56.4 TPI
- Series
- coarse
Drilling
- Tap drill
- 2.05 mm · .0807
- Inch substitute
- #46 · .0810
- Close fit
- 2.7 mm
- Normal fit
- 2.9 mm
- Free fit
- 3.1 mm
Nearest inch
- Thread
- #3-48
- Major diameter
- .0990″
- Threads per inch
- 48
- Tap drill
- #47
- 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 |
|---|---|---|---|
| 2.05 mm | .0807 | 2.05 | 77% |
| #46 | .0810 | 2.06 | 76% |
| #45 | .0820 | 2.08 | 71% |
| 2.1 mm | .0827 | 2.1 | 68% |
| #44 | .0860 | 2.18 | 54% |
| 2.2 mm | .0866 | 2.2 | 51% |
Neighboring sizes
- M1.6 × 0.35tap 1.25 mm
- M2 × 0.4tap 1.6 mm
- M3 × 0.5tap 2.5 mm
- M3 × 0.35tap 2.65 mm
- M4 × 0.7tap 3.3 mm
- M4 × 0.5tap 3.5 mm
Questions
What does M2.5 × 0.45 mean?
An ISO metric thread with a 2.5 mm major diameter and a 0.45 mm pitch (the distance from one thread crest to the next). It’s the coarse pitch for M2.5.
Can I use a #46 drill instead?
Usually. #46 is .0810″ against .0807″ for the 2.05 mm drill, which changes the thread engagement by a few percent at most.