US Machine Screws - Dimensions

Machine screw diameters and thread specifications. Look up thread diameter, nearest fractional size, and TPI (threads per inch) for US machine screws from size 0 to 3/8".

Size No.	Thread Diameter (in)	Nearest Fractional (in)	Fine TPI	Coarse TPI
0	0.0600	1/16	80	—
1	0.0730	5/64	72	64
2	0.0860	3/32	64	56
3	0.0990	7/64	56	48
4	0.1120	7/64	48	40
5	0.1250	1/8	44	40
6	0.1380	9/64	40	32
8	0.1640	5/32	36	32
10	0.1900	3/16	32	24
12	0.2160	7/32	28	24
1/4	0.2500	1/4	28	20
5/16	0.3125	5/16	24	18
3/8	0.3750	3/8	24	16

Reference Information

TPI = Threads per inch
Fine threads are according to UNF (Unified National Fine Thread) standard
Coarse threads are according to UNC (Unified National Coarse Thread) standard

US Machine Screws - Dimensions | MEPKit Engineering Tools | MEPKit