Z drill bit size

Z drill = .4130 in = 10.49 mm. Closest metric drill: 10.5 mm.

Nearby drill sizes

Drill	Type	Inch	mm	Difference
25/64	fraction	.3906 in	9.922	-22.4 thou
X	letter	.3970 in	10.084	-16.0 thou
Y	letter	.4040 in	10.262	-9.0 thou
13/32	fraction	.4063 in	10.319	-6.7 thou
Z	letter	.4130 in	10.490	0.0 thou
27/64	fraction	.4219 in	10.716	8.9 thou
7/16	fraction	.4375 in	11.112	24.5 thou
29/64	fraction	.4531 in	11.509	40.1 thou
15/32	fraction	.4688 in	11.906	55.8 thou

1 thou = 0.001 in = 0.0254 mm. Drills a few thou apart are usually interchangeable for clearance holes, but not for tap drills or reamer pilots.