M16 × 2.0 Tap Drill Size & Thread Specs

Everything for a M16 × 2.0 coarse pitch thread on one page: tap drill (14 mm), clearance holes, wrench and hex key sizes, and the nearest inch thread.

M16 × 2.0 · tap with
14 mm drill
.5512″
14 mm · 77% thread
Inch drill
35/64 · .5469
Clearance
17 / 17.5 mm
Wrench
24 mm
Cap screw key
14 mm

Thread

Nominal size
M16 · .6299″
Pitch
2 mm · 12.7 TPI
Series
coarse
fine pitch
M16 × 1.5

Drilling

Tap drill
14 mm · .5512
Inch substitute
35/64 · .5469
Close fit
17 mm
Normal fit
17.5 mm
Free fit
18.5 mm

Tools

Hex head (ISO 4017)
24 mm
Hex head (DIN 933)
24 mm
Socket head cap key
14 mm
Button head key
10 mm
Flat head key
10 mm

Nearest inch

Thread
5/8-11
Major diameter
.6250″
Threads per inch
11
Tap drill
17/32
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
35/64.546913.8981%
14 mm.55121477%
9/16.562514.2966%
14.5 mm.570914.558%
37/64.578114.6851%

Neighboring sizes

Questions

What does M16 × 2.0 mean?
An ISO metric thread with a 16 mm major diameter and a 2 mm pitch (the distance from one thread crest to the next). It’s the coarse pitch for M16.
Can I use a 35/64 drill instead?
Usually. 35/64 is .5469″ against .5512″ for the 14 mm drill, which changes the thread engagement by a few percent at most.