BS 4320 British Standard For Metal Washers
BS 4320 British Standard For Metal Washers (Normal Diameter Sizes)
| Nominal Size of Bolt or Screw | Inside Diameter | Outside Diameter | Thickness | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Form A Normal Range | Form B Light Range | |||||||||||
| Nom | Max | Min | Nom | Max | Min | Nom | Max | Min | Nom | Max | Min | |
| BS 4320 - M1.0 | 1.1 | 1.25 | 1.1 | 2.5 | 2.5 | 2.3 | 0.3 | 0.4 | 0.2 | ... | ... | ... |
| BS 4320 - M1.2 | 1.3 | 1.45 | 1.3 | 3 | 3 | 2.8 | 0.3 | 0.4 | 0.2 | ... | ... | ... |
| BS 4320 - M1.4 | 1.5 | 1.65 | 1.5 | 3 | 3 | 2.8 | 0.3 | 0.4 | 0.2 | ... | ... | ... |
| BS 4320 - M1.6 | 1.7 | 1.85 | 1.7 | 4 | 4 | 3.7 | 0.3 | 0.4 | 0.2 | ... | ... | ... |
| BS 4320 - M2.0 | 2.2 | 2.35 | 2.2 | 5 | 5 | 4.7 | 0.3 | 0.4 | 0.2 | ... | ... | ... |
| BS 4320 - M2.2 | 2.4 | 2.55 | 2.4 | 5 | 5 | 4.7 | 0.5 | 0.6 | 0.4 | ... | ... | ... |
| BS 4320 - M2.5 | 2.7 | 2.85 | 2.7 | 6.5 | 6.5 | 6.2 | 0.5 | 0.6 | 0.4 | ... | ... | ... |
| BS 4320 - M3 | 3.2 | 3.4 | 3.2 | 7 | 7 | 6.7 | 0.5 | 0.6 | 0.4 | ... | ... | ... |
| BS 4320 - M3.5 | 3.7 | 3.9 | 3.7 | 7 | 7 | 6.7 | 0.5 | 0.6 | 0.4 | ... | ... | ... |
| BS 4320 - M4 | 4.3 | 4.5 | 4.3 | 9 | 9 | 8.7 | 0.8 | 0.9 | 0.7 | ... | ... | ... |
| BS 4320 - M4.5 | 4.8 | 5 | 4.8 | 9 | 9 | 8.7 | 0.8 | 0.9 | 0.7 | ... | ... | ... |
| BS 4320 - M5 | 5.3 | 5.5 | 5.3 | 10 | 10 | 9.7 | 1 | 1.1 | 0.9 | ... | ... | ... |
| BS 4320 - M6 | 6.4 | 6.7 | 6.4 | 12.5 | 12.5 | 12.1 | 1.6 | 1.8 | 1.4 | 0.8 | 0.9 | 0.7 |
| BS 4320 - M7 | 7.4 | 7.7 | 7.4 | 14 | 14 | 13.6 | 1.6 | 1.8 | 1.4 | 0.8 | 0.9 | 0.7 |
| BS 4320 - M8 | 8.4 | 8.7 | 8.4 | 17 | 17 | 16.6 | 1.6 | 1.8 | 1.4 | 1 | 1.1 | 0.9 |
| BS 4320 - M10 | 10.5 | 10.9 | 10.5 | 21 | 21 | 20.5 | 2 | 2.2 | 1.8 | 1.25 | 1.45 | 1.05 |
| BS 4320 - M12 | 13 | 13.4 | 13 | 24 | 24 | 23.5 | 2.5 | 2.7 | 2.3 | 1.6 | 1.8 | 1.4 |
| BS 4320 - M14 | 15 | 15.4 | 15 | 28 | 28 | 27.5 | 2.5 | 2.7 | 2.3 | 1.6 | 1.8 | 1.4 |
| BS 4320 - M16 | 17 | 17.4 | 17 | 30 | 30 | 29.5 | 3 | 3.3 | 2.7 | 2 | 2.2 | 1.8 |
| BS 4320 - M18 | 19 | 19.5 | 19 | 34 | 34 | 33.2 | 3 | 3.3 | 2.7 | 2 | 2.2 | 1.8 |
| BS 4320 - M20 | 21 | 21.5 | 21 | 37 | 37 | 36.2 | 3 | 3.3 | 2.7 | 2 | 2.2 | 1.8 |
| BS 4320 - M22 | 23 | 23.5 | 23 | 39 | 39 | 38.2 | 3 | 3.3 | 2.7 | 2 | 2.2 | 1.8 |
| BS 4320 - M24 | 25 | 25.5 | 25 | 44 | 44 | 43.2 | 4 | 4.3 | 3.7 | 2.5 | 2.7 | 2.3 |
| BS 4320 - M27 | 28 | 28.5 | 28 | 50 | 50 | 49.2 | 4 | 4.3 | 3.7 | 2.5 | 2.7 | 2.3 |
| BS 4320 - M30 | 31 | 31.6 | 31 | 56 | 56 | 55 | 4 | 4.3 | 3.7 | 2.5 | 2.7 | 2.3 |
| BS 4320 - M33 | 34 | 34.6 | 34 | 60 | 60 | 59 | 5 | 5.6 | 4.4 | 3 | 3.3 | 2.7 |
| BS 4320 - M36 | 37 | 37.6 | 37 | 66 | 66 | 65 | 5 | 5.6 | 4.4 | 3 | 3.3 | 2.7 |
| BS 4320 - M39 | 40 | 40.6 | 40 | 72 | 72 | 71 | 6 | 6.6 | 5.4 | 3 | 3.3 | 2.7 |
BS 4320 British Standard For Metal Washers (Large Diameter Sizes)
| Nominal Size of Bolt or Screw | Inside Diameter | Outside Diameter | Thickness | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Form C Normal Range | Form D Light Range | |||||||||||
| Nom | Max | Min | Nom | Max | Min | Nom | Max | Min | Nom | Max | Min | |
| BS 4320 - M4 | 4.3 | 4.5 | 4.3 | 10 | 10 | 9.7 | 0.8 | 0.9 | 0.7 | ... | ... | ... |
| BS 4320 - M5 | 5.3 | 5.5 | 5.3 | 12.5 | 12.5 | 12.1 | 1 | 1.1 | 0.9 | ... | ... | ... |
| BS 4320 - M6 | 6.4 | 6.7 | 6.4 | 14 | 14 | 13.6 | 1.6 | 1.8 | 1.4 | 0.8 | 0.9 | 0.7 |
| BS 4320 - M8 | 8.4 | 8.7 | 8.4 | 21 | 21 | 20.5 | 1.6 | 1.8 | 1.4 | 1 | 1.1 | 0.9 |
| BS 4320 - M10 | 10.5 | 10.9 | 10.5 | 24 | 24 | 23.5 | 2 | 2.2 | 1.8 | 1.25 | 1.45 | 1.05 |
| BS 4320 - M12 | 13 | 13.4 | 13 | 28 | 28 | 27.5 | 2.5 | 2.7 | 2.3 | 1.6 | 1.8 | 1.4 |
| BS 4320 - M14 | 15 | 15.4 | 15 | 30 | 30 | 29.5 | 2.5 | 2.7 | 2.3 | 1.6 | 1.8 | 1.4 |
| BS 4320 - M16 | 17 | 17.4 | 17 | 34 | 34 | 33.2 | 3 | 3.3 | 2.7 | 2 | 2.2 | 1.8 |
| BS 4320 - M18 | 19 | 19.5 | 19 | 37 | 37 | 36.2 | 3 | 3.3 | 2.7 | 2 | 2.2 | 1.8 |
| BS 4320 - M20 | 21 | 21.5 | 21 | 39 | 39 | 38.2 | 3 | 3.3 | 2.7 | 2 | 2.2 | 1.8 |
| BS 4320 - M22 | 23 | 23.5 | 23 | 44 | 44 | 43.2 | 3 | 3.3 | 2.7 | 2 | 2.2 | 1.8 |
| BS 4320 - M24 | 25 | 25.5 | 25 | 50 | 50 | 49.2 | 4 | 4.3 | 3.7 | 2.5 | 2.7 | 2.3 |
| BS 4320 - M27 | 28 | 28.5 | 28 | 56 | 56 | 55 | 4 | 4.3 | 3.7 | 2.5 | 2.7 | 2.3 |
| BS 4320 - M30 | 31 | 31.6 | 31 | 60 | 60 | 59 | 4 | 4.3 | 3.7 | 2.5 | 2.7 | 2.3 |
| BS 4320 - M33 | 34 | 34.6 | 34 | 66 | 66 | 65 | 5 | 5.6 | 4.4 | 3 | 3.3 | 2.7 |
| BS 4320 - M36 | 37 | 37.6 | 37 | 72 | 72 | 71 | 5 | 5.6 | 4.4 | 3 | 3.3 | 2.7 |
| BS 4320 - M39 | 40 | 40.6 | 40 | 77 | 77 | 76 | 6 | 6.6 | 5.4 | 3 | 3.3 | 2.7 |
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