BS 1981 80 Degree Raised Countersunk Head Screws

Nom.Size of Screw	Basic Dia. D	Threads per Inch		Dia. of Head A		Depth of Head B		Width of Slot H		Depth of Slot J
Nom.Size of Screw	Basic Dia. D	UNC	UNF	Max.	Min.	Max.	Min.	Max.	Min.	Depth of Slot J
BS 1981 - 4	0.112	40	...	0.211	0.194	0.067	...	0.039	0.031	0.025
BS 1981 - 6	0.138	32	...	0.26	0.242	0.083	...	0.048	0.039	0.031
BS 1981 - 8	0.164	32	...	0.31	0.291	0.1	...	0.054	0.045	0.037
BS 1981 - 10	0.19	24 c	32	0.359	0.339	0.116	...	0.06	0.05	0.044
BS 1981 - 1⁄4	0.25	20	28	0.473	0.45	0.153	...	0.075	0.064	0.058
BS 1981 - 5⁄16	0.3125	18	24	0.593	0.565	0.191	...	0.084	0.072	0.073
BS 1981 - 3⁄8	0.375	16	24	0.712	0.681	0.23	...	0.094	0.081	0.086
BS 1981 - 7⁄16	0.4375	14	20	0.753	0.719	0.223	...	0.094	0.081	0.086
BS 1981 - 1⁄2	0.5	13	20	0.808	0.77	0.223	...	0.106	0.091	0.086
BS 1981 - 5⁄8	0.625	11	18	1.041	0.996	0.298	...	0.133	0.116	0.113
BS 1981 - 3⁄4	0.75	10	16	1.275	1.223	0.372	...	0.149	0.131	0.141
a All dimensions, except J, given for the No. 4 to 38-inch sizes, incl., also apply to all the 80° Raised Countersunk Head Screws given in the Standard. b Also available with recessed heads. c Non-preferred. d By arrangement may also be 0.468.