Cap Screws

Notes: All linear dimensions in milli metresDimensions generally to BS EN ISO 4762 BS 3643- 2 & BS 4168 (superceded)

Nominal Thread.Hex Socket Size

Body diameter and Head height

Head DiaSoc. length

Size Pitch Max Min Max Min

J D /H A K

M3 0.5 2.50 3.00 2.86 5.50 5.20 1.3

M4 0.70 3.00 4.00 3.82 7.00 6.64 2.00

M5 0.8 4.00 5.00 4.82 8.50 8.14 2.70

M6 1.0 5.00 6.00 5.82 10.00 9.64 3.30

M8 1.25 6.00 8.00 7.78 13.00 12.57 4.3

M10 1.5 8.00 10.00 9.78 16.00 15.57 5.50

M12 1.75 10.00 12.00 11.73 18.00 17.57 6.60

M16 2.0 14.00 16.00 15.73 24.00 23.48 8.80

M20 2.5 17.00 20.00 19.67 30.00 29.48 10.70

M24 3.0 19.00 24.00 23.67 36.00 35.38 12.90

Countersunk Screws (Flat Head Screws)

The dimensions are generally in accordance with BS EN ISO 10642:1998.   This supersedes BS 4168-8.

Nominal size

Body DiaThread Pitch

Hex Socket Size

Max Cone Dia

Head DiaHead Height

Soc. length

D(max) D(min) J A1 A_max A_Min H K

M3 3.00 2.86 0.5 2,0 6,72 6,00 5,82 1,86 1,05

M4 4.00 3.82 0.70 2,5 8,96 8,00 7,78 2,48 1,49

M5 5.00 4.82 0.8 3,0 11,2 10,00 9,78 3,1 1,86

M6 6.00 5.82 1.0 4,0 13,44 12,00 11,75 3,72 2,16

M8 8.00 7.78 1.25 5,0 17,92 16,00 15,73 4,96 2,85

M10 10.00 9.78 1.5 6,0 22,4 20,00 19,67 6,2 3,60

M12 12.00 11.73 1.75 8,0 26,88 24,00 23,67 7,44 4,35

M16 16.00 15.73 2.0 10,0 33,6 32,00 29,67 8,8 4,89

M20 20.00 19.67 2.5 10,0 40,32 40,00 35,61 10,16 5,49

Sites Providing Information On Socket Screws

1. Dimensional Data - Socket Cap Screws ..Holo-krome dimensional data2. PTS_uk ..Some useful dimensions of socket screws etc3. Fullermetric .Din /ISO dimensions4. Ondrives Goto Fasteners Lots of Information on metric screws