BS 4183 Slotted Pan Head Machine Screws

Nominal Size da	Head Diameter D		Head Height k		Radius Under Head r	Transition Diameter da	Thread Length b	Thread Run-out a	Slot Width n		Slot Depth t
Nominal Size da	Max. 2d	Min.	Max. 0.6d	Max 0.4d	Min.	Max.	Min	Max. 2pb	Max.	Min.	Max. 0.6k	Min. 0.4k
BS 4183 - M2.5	5	4.7	1.5	1.36	1	0.1	18	0.9	0.8	0.66	0.9	0.6
BS 4183 - M3	6	5.7	1.8	1.66	1.2	0.1	19	1	1	0.86	1.08	0.72
BS 4183 - M4	7	6.64	2.1	1.96	1.4	0.2	20	1.2	1	0.86	1.26	0.84
BS 4183 - M4	8	7.64	2.4	2.26	1.6	0.2	22	1.4	1.2	1.06	1.44	0.96
BS 4183 - M4.5	9	8.64	2.7	2.56	1.8	0.2	24	1.5	1.2	1.06	1.62	1.08
BS 4183 - M5	10	9.64	3	2.86	2	0.2	25	1.6	1.51	1.26	1.8	1.2
BS 4183 - M6	12	11.57	3.6	3.42	2.5	0.25	28	2	1.91	1.66	2.16	1.44
BS 4183 - M8	16	15.57	4.8	4.62	3.2	0.4	34	2.5	2.31	2.06	2.88	1.92
BS 4183 - M10	20	19.48	6	5.82	4	0.4	40	3	2.81	2.56	3.6	2.4
a Nominal sizes shown in parentheses are non-preferred. b See Lengths of Thread on Screws on page 1606. All dimensions are in millimeters. For dimensional notation, see diagram on page 1610. Recessed head screws are also standard and available. For dimensions, see British Standard.