Machine Screws

Tapping & Clearance Hole Information
(Size 7/16" through 11/16" Diameter)

Machine Screw Size Number of Threads Per Inch Minor Dia. Tap Drills Clearance Hole Drills

Aluminum, Brass & Plastics

75% Thread 

Stainless Steel, Steels & Iron

50% Thread

All Materials
Close Fit Free Fit
No. or Dia. Major Dia. Drill Size Decimal Equiv. Drill Size Decimal Equiv. Drill Size Decimal Equiv. Drill Size Decimal Equiv.

7/16

.4375

14 .3499 U .3680 25/64 .3906

29/64

.4531

15/32

.4687

20 .3762 25/64 .3906 13/32 .4062
28 .3937 Y .4040 Z .4130
1/2 .5000 13 .4056 27/64 .4219 29/64 .4531 33/64 .5156 17/32 .5312
20 .4387 29/64 .4531 15/32 .4688
28 .4562 15/32 .4688 15/32 .4688
9/16 .5625 12 .4603 31/64 .4844 33/64 .5156 37/64 .5781 19/32 .5938
18 .4943 33/64 .5156 17/32 .5312
24 .5114 33/64 .5156 17/32 .5312
5/8 .6250 11 .5135 17/32 .5312 9/16 .5625 41/64 .6406 21/32 .6562
18 .5568 37/64 .5781 19/32 .5938
24 .5739 37/64 .5781 19/32 .5938
11/16 .6875 24 .6364 41/64 .6406 21/32 .6562 45/64 .7031 23/32 .6562

Tables for other screw sizes #0 - #6
#8 - 3/8
3/4 - 1-3/16
1-1/4 - 1-3/4