Machine Screw Size

Machine Screw Sizes gauge sizes range from #000 to #14.

Starting at #0 size which is .060 inch at the thread's major diameter, all sizes above this (1-14) are larger by increments of .013 inch.

"four forty" screw is a #4 screw with 40 threads per inch.
"six thirty-two is a #6 screw with 32 threads per inch.
"eight thirty-two" is a #8 screw with 32 threads per inch.
"ten thirty-two" screw is a #10 screw with 32 threads per inch.

0	.0600	uncommon
1	.0730	uncomon
2	.0860	uncommon
3	.0990	uncommon
4	.1120
5	.1250	uncommon
6	.1380	commonly used small
8	.1640	very common
10	.1900	very common
12	.2160	common but large
1/4	.2500
5/16	.3125
3/8	.3750