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  4. BS 4320 British Standard Black Metal Washers

BS 4320 British Standard Black Metal Washers

BS 4320 British Standard Black Metal Washers

BS 4320 British Standard Black Metal Washers(Normal Diameter Sizes (Form E))

Nom Bolt or Screw Size Inside Diameter Outside Diameter Thickness
Nom Max Min. Nom Max Min. Nom Max Min.
BS 4320 - M5 5.5 5.8 5.5 10 10 9.2 1 1.2 0.8
BS 4320 - M6 6.6 7 6.6 12.5 12.5 11.7 1.6 1.9 1.3
BS 4320 - M7 7.6 8 7.6 14 14 13.2 1.6 1.9 1.3
BS 4320 - M8 9 9.4 9 17 17 16.2 1.6 1.9 1.3
BS 4320 - M10 11 11.5 11 21 21 20.2 2 2.3 1.7
BS 4320 - M12 14 14.5 14 24 24 23.2 2.5 2.8 2.2
BS 4320 - M14 16 16.5 16 28 28 27.2 2.5 2.8 2.2
BS 4320 - M16 18 18.5 18 30 30 29.2 3 3.6 2.4
BS 4320 - M18 20 20.6 20 34 34 32.8 3 3.6 2.4
BS 4320 - M20 22 22.6 22 37 37 35.8 3 3.6 2.4
BS 4320 - M22 24 24.6 24 39 39 37.8 3 3.6 2.4
BS 4320 - M24 26 26.6 26 44 44 42.8 4 4.6 3.4
BS 4320 - M27 30 30.6 30 50 50 48.8 4 4.6 3.4
BS 4320 - M30 33 33.8 33 56 56 54.5 4 4.6 3.4
BS 4320 - M33 36 36.8 36 60 60 58.5 5 6 4
BS 4320 - M36 39 39.8 39 66 66 64.5 5 6 4
BS 4320 - M39 42 42.8 42 72 72 70.5 6 7 5
BS 4320 - M42 45 45.8 45 78 78 76.5 7 8.2 5.8
BS 4320 - M45 48 48.8 48 85 85 83 7 8.2 5.8
BS 4320 - M48 52 53 52 92 92 90 8 9.2 6.8
BS 4320 - M52 56 57 56 98 98 96 8 9.2 6.8
BS 4320 - M56 62 63 62 105 105 103 9 10.2 7.8
BS 4320 - M60 66 67 66 110 110 108 9 10.2 7.8
BS 4320 - M64 70 71 70 115 115 113 9 10.2 7.8
BS 4320 - M68 74 75 74 120 120 118 10 11.2 8.8

BS 4320 British Standard Black Metal Washers(Large Diameter Sizes (Form F))

Nom Bolt or Screw Size Inside Diameter Outside Diameter Thickness
Nom Max Min. Nom Max Min. Nom Max Min.
BS 4320 - M8 9 9.4 9 21 21 20.2 1.6 1.9 1.3
BS 4320 - M10 11 11.5 11 24 24 23.2 2 2.3 1.7
BS 4320 - M12 14 14.5 14 28 28 27.2 2.5 2.8 2.2
BS 4320 - M14 16 16.5 16 30 30 29.2 2.5 2.8 2.2
BS 4320 - M16 18 18.5 18 34 34 32.8 3 3.6 2.4
BS 4320 - M18 20 20.6 20 37 37 35.8 3 3.6 2.4
BS 4320 - M20 22 22.6 22 39 39 37.8 3 3.6 2.4
BS 4320 - M22 24 24.6 24 44 44 42.8 3 3.6 2.4
BS 4320 - M24 26 26.6 26 50 50 48.8 4 4.6 3.4
BS 4320 - M27 30 30.6 30 56 56 54.5 4 4.6 3.4
BS 4320 - M30 33 33.8 33 60 60 58.5 4 4.6 3.4
BS 4320 - M33 36 36.8 36 66 66 64.5 5 6 4
BS 4320 - M36 39 39.8 39 72 72 70.5 5 6 4
BS 4320 - M39 42 42.8 42 77 77 75.5 6 7 5

BS 4320 British Standard Black Metal Washers(Extra Large Diameter Sizes (Form G))

Nom Bolt or Screw Size Inside Diameter Outside Diameter Thickness
Nom Max Min. Nom Max Min. Nom Max Min.
BS 4320 - M5 5.5 5.8 5.5 15 15 14.2 1.6 1.9 1.3
BS 4320 - M6 6.6 7 6.6 18 18 17.2 2 2.3 1.7
BS 4320 - M7 7.6 8 7.6 21 21 20.2 2 2.3 1.7
BS 4320 - M8 9 9.4 9 24 24 23.2 2 2.3 1.7
BS 4320 - M10 11 11.5 11 30 30 29.2 2.5 2.8 2.2
BS 4320 - M12 14 14.5 14 36 36 34.8 3 3.6 2.4
BS 4320 - M14 16 16.5 16 42 42 40.8 3 3.6 2.4
BS 4320 - M16 18 18.5 18 48 48 46.8 4 4.6 3.4
BS 4320 - M18 20 20.6 20 54 54 52.5 4 4.6 3.4
BS 4320 - M20 22 22.6 22 60 60 58.5 5 6 4
BS 4320 - M22 24 24.6 24 66 66 64.5 5 6 4
BS 4320 - M24 26 26.6 26 72 72 70.5 6 7 5
BS 4320 - M27 30 30.6 30 81 81 79 6 7 5
BS 4320 - M30 33 33.8 33 90 90 88 8 9.2 6.8
BS 4320 - M33 36 36.8 36 99 99 97 8 9.2 6.8
BS 4320 - M36 39 39.8 39 108 108 106 10 11.2 8.8
BS 4320 - M39 42 42.8 42 117 117 115 10 11.2 8.8
  • All dimensions are in millimeters.
  • Nominal bolt or screw sizes shown in parentheses are nonpreferred.