BS 4183 Slotted Raised Countersunk Head Machine Screws

Nominal Size d^a	Head Diameter D		Head Height k		Radius r^b	Thread Length b	Thread Run-out a	Flushness Tolerance^c	Slot Width n		Slot Depth t
Nominal Size d^a	Max. (Theor. Sharp) 2d	Min. 1.75d	Max. 0.5d	Min. 0.45d	Radius r^b	Min.	Max. 2p^d	Max.	Max.	Min.	Max. 0.3d	Min. 0.2d
BS 4183 - M1	2	1.75	0.5	0.45	0.1	e	0.5	....	0.45	0.31	0.3	0.2
BS 4183 - M1.2	2.4	2.1	0.6	0.54	0.1	e	0.5	....	0.5	0.36	0.36	0.24
BS 4183 - M1.4	2.8	2.45	0.7	0.63	0.1	e	0.6	....	0.5	0.36	0.42	0.28
BS 4183 - M1.6	3.2	2.8	0.8	0.72	0.1	15	0.7	....	0.6	0.46	0.48	0.32
BS 4183 - M2.0	4	3.5	1	0.9	0.1	16	0.8	....	0.7	0.56	0.6	0.4
BS 4183 - M2.2	4.4	3.85	1.1	0.99	0.1	17	0.9	....	0.8	0.66	0.66	0.44
BS 4183 - M2.5	5	4.38	1.25	1.12	0.1	18	0.9	0.1	0.8	0.66	0.75	0.5
BS 4183 - M3	6	5.25	1.5	1.35	0.1	19	1	0.12	1	0.86	0.9	0.6
BS 4183 - M3.5	7	6.1	1.75	1.57	0.2	20	1.2	0.13	1	0.86	1.05	0.7
BS 4183 - M4	8	7	2	1.8	0.2	22	1.4	0.15	1.2	1.06	1.2	0.8
BS 4183 - M4.5	9	7.85	2.25	2.03	0.2	24	1.5	0.17	1.2	1.06	1.35	0.9
BS 4183 - M5	10	8.75	2.5	2.25	0.2	25	1.6	0.19	1.51	1.26	1.5	1
BS 4183 - M6	12	10.5	3	2.7	0.25	28	2	0.23	1.91	1.66	1.8	1.2
BS 4183 - M8	16	14	4	3.6	0.4	34	2.5	0.29	2.31	2.06	2.4	1.6
BS 4183 - M10	20	17.5	5	4.5	0.4	40	3	0.37	2.81	2.56	3	2
BS 4183 - M12	24	21	6	5.4	0.6	46	3.5	0.44	3.31	3.06	3.6	2.4
BS 4183 - M14	28	24.5	7	6.3	0.6	52	4	0.52	3.31	3.06	4.2	2.8
BS 4183 - M16	32	28	8	7.2	0.6	58	4	0.6	4.37	4.07	4.8	3.2
BS 4183 - M18	36	31.5	9	8.1	0.6	64	5	0.67	4.37	4.07	5.4	3.6
BS 4183 - M20	40	35	10	9	0.8	70	5	0.75	5.37	5.07	6	4
a Nominal sizes shown in parentheses are non-preferred. b See Radius Under the Head of Screws description in text. c See 90-Degree Countersunk Head Screws description in text. d See text following table in Lengths of Thread on Screws description in text. e Threaded up to head. All dimensions are given in millimeters. For dimensional notation, see diagram on page 1610. Recessed head screws are also standard and are available. For dimen- sions see British Standard.