Imperial Flat Head Countersunk Socket

UNC/UNF

*Flat Head Countersunk

S325 - UNC/UNF Bare Steel

ANSI/ASME B18.3

1986

Coarse Thread
Diameter d		#6-32	#8-32	#10-24	1/4-20	5/16-18	3/8-16	7/16-14	1/2-13	5/8-11	3/4-10	7/8-9	1-8
Diameter Code		006	008	010	014	016	018	020	024	026	028	030	034
t		.066	.076	.087	.111	.135	.159	.159	.172	.220	.220	.248	.297
s		⁵/₆₄	³/₃₂	¹/₈	⁵/₃₂	³/₁₆	⁷/₃₂	¹/₄	⁵/₁₆	³/₈	½	⁹/₁₆	⁵/₈
s		.078	.094	.125	.156	.188	.219	.250	.312	.375	.500	.562	.625
k max.		.097	.112	.127	.161	.198	.234	.234	.251	.324	.396	.468	.540
d₁ max.		.307	.359	.411	.531	.656	.781	.844	.938	1.188	1.438	1.688	1.938
Length	Code	Pkg.
Order Number -> Order Number -> 1/4 x 2-1/2 = S325-014-0250 (Diameter Code x Length Code)
1/4	0025	100	100
3/8	0038	100	100	100	100	100
1/2	0050	100	100	100	100	100	100
5/8	0063	100	100	100	100	100	100
3/4	0075	100	100	100	100	100	100	100	100
1	0100	100	100	100	100	100	100	100	100	50
1-1/4	0125		100	100	100	100	100	100	100	50	25
1-1/2	0150		100	100	100	100	100	100	100	50	25
1-3/4	0175		100	100	100	100	100	100	50	50	25
2	0200	100	100	100	100	100	100	50	50	50	25
2-1/4	0225				100	100	100		50	25	25
2-1/2	0250			100	100	100	100	50	50	25	25
3	0300				100	100	100	50	50	25	25	25
3-1/2	0350				100		100	50	50	25	25
4	0400				100	100	100		50	25	25	25	10
4-1/2	0450						50		50	25	25
5	0500						50		50	25	25		10
6	0600						50		50	25	25

Fine Thread
Diameter d		10-32	1/4-28	5/16-24	3/8-24	1/2-20
Diameter Code		010	014	016	018	024
t		.087	.111	.135	.159	.172
s		¹/₈	⁵/₃₂	³/₁₆	⁷/₃₂	5/16
s		.125	.156	.188	.219	.312
k max.		.127	.161	.198	.234	.251
d₁ max.		.411	.531	.656	.781	.938
Length	Code	Pkg.
Order Number -> Order Number -> 1/4 x 2-1/2 = S325-014-0250-F (Diameter Code x Length Code)(Fine Thread add -F)
1/4	0025	100
3/8	0038	100	100
1/2	0050	100	100	100
5/8	0063	100	100	100
3/4	0075	100	100	100		100
1	0100	100	100	100	100	100
1-1/4	0125	100	100	100
1-1/2	0150	100	100	100	100	100
1-3/4	0175	100	100	100
2	0200	100	100		100	100

*82 degree countersink +/- 2 degrees