M24 × 3.0 Tap Drill Size & Thread Specs
Everything for a M24 × 3.0 coarse pitch thread on one page: tap drill (21 mm), clearance holes, wrench and hex key sizes, and the nearest inch thread.
SP-TD-01 · M24 × 3.0
M24 × 3.0 specs
SizePlate
M24 × 3.0 · tap with
21 mm drill
.8268″
21 mm · 77% thread
- Inch drill
- 53/64 · .8281
- Clearance
- 25 / 26 mm
- Wrench
- 36 mm
- Cap screw key
- 19 mm
Thread
- Nominal size
- M24 · .9449″
- Pitch
- 3 mm · 8.5 TPI
- Series
- coarse
- fine pitch
- M24 × 2.0
Drilling
- Tap drill
- 21 mm · .8268
- Inch substitute
- 53/64 · .8281
- Close fit
- 25 mm
- Normal fit
- 26 mm
- Free fit
- 28 mm
Tools
- Hex head (ISO 4017)
- 36 mm
- Hex head (DIN 933)
- 36 mm
- Socket head cap key
- 19 mm
- Button head key
- —
- Flat head key
- —
Nearest inch
- Thread
- 1-8
- Major diameter
- 1.0000″
- Threads per inch
- 8
- Tap drill
- 7/8
- 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 |
|---|---|---|---|
| 21 mm | .8268 | 21 | 77% |
| 53/64 | .8281 | 21.03 | 76% |
| 27/32 | .8438 | 21.43 | 66% |
| 21.5 mm | .8465 | 21.5 | 64% |
| 55/64 | .8594 | 21.83 | 56% |
| 22 mm | .8661 | 22 | 51% |
| 7/8 | .8750 | 22.22 | 46% |
Neighboring sizes
Questions
What does M24 × 3.0 mean?
An ISO metric thread with a 24 mm major diameter and a 3 mm pitch (the distance from one thread crest to the next). It’s the coarse pitch for M24.
Can I use a 53/64 drill instead?
Usually. 53/64 is .8281″ against .8268″ for the 21 mm drill, which changes the thread engagement by a few percent at most.