M24 × 2.0 Tap Drill Size & Thread Specs

Everything for a M24 × 2.0 fine pitch thread on one page: tap drill (22 mm), clearance holes, wrench and hex key sizes, and the nearest inch thread.

M24 × 2.0 · tap with
22 mm drill
.8661″
22 mm · 77% thread
Inch drill
55/64 · .8594
Clearance
25 / 26 mm
Wrench
36 mm
Cap screw key
19 mm

Thread

Nominal size
M24 · .9449″
Pitch
2 mm · 12.7 TPI
Series
fine
coarse pitch
M24 × 3.0

Drilling

Tap drill
22 mm · .8661
Inch substitute
55/64 · .8594
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.

DrillDecimalmmThread
55/64.859421.8384%
22 mm.86612277%
7/8.875022.2268%
22.5 mm.885822.558%
57/64.890622.6253%

Neighboring sizes

Questions

What does M24 × 2.0 mean?
An ISO metric thread with a 24 mm major diameter and a 2 mm pitch (the distance from one thread crest to the next). It’s the fine pitch for M24.
Can I use a 55/64 drill instead?
Usually. 55/64 is .8594″ against .8661″ for the 22 mm drill, which changes the thread engagement by a few percent at most.