Nominal Size And Thread Dia Inside Hole Diameter Maximum Inside Hole Diameter Minimum Outside Hole Diameter Maximum Outside Hole Diameter Minimum Height Maximum Height Minimum Nominal Thickness
M1.6 1.8 1.7 3.4 3.52 0.51 0.36 0.16
M2 2.3 2.2 4.6 4.42 0.53 0.38 0.16
(M2.2) 2.5 2.4 5.2 5.02 0.53 0.38 0.16
M2.5 2.8 2.705 5.8 5.62 0.53 0.38 0.16
M3 3.32 3.2 6.4 6.18 0.61 0.46 0.16
(M3.5) 3.82 3.7 6.9 6.68 0.79 0.63 0.20
M4 4.42 4.3 8.1 7.88 0.84 0.69 0.28
M5 5.43 5.3 9.2 8.98 0.89 0.74 0.30
M6 6.55 6.4 11.5 11.23 1.14 0.99 0.40
M8 8.55 8.4 15.0 14.73 1.40 1.25 0.40
M10 10.68 10.5 19.6 19.27 1.70 1.55 0.55
M12 13.18 13.0 22.00 21.67 1.90 1.65 0.65
(M14) 15.18 15.0 25.5 25.17 2.06 1.80 0.55
M16 17.18 17.0 27.8 27.47 2.41 2.16 0.70
(M18) 19.21 19.0 31.3 30.91 2.41 2.16 0.70
M20 21.21 21.0 34.7 34.31 2.66 2.16 0.70

Please Note - Stock Sizes
Sizes shown in brackets are non-prefered, and are not usually stock sizes.

Please Note - Tolerances
Tolerances to be in accordance with those specified for the thickness of material in table 2 of BS2870. 'Rolled copper and copper alloys, sheet strip and foil', or table 4 of BS1449, 'Steel plate, sheet and strip', Part 4, 'Stainless and heat resisting plate, sheet and strip', as appropriate.