BS 4183 Slotted Raised Countersunk Head Machine Screws

BS 4183 Slotted Raised Countersunk Head Machine Screws

Nominal Size da Head Diameter D Head Height k Radius rb Thread Length b Thread Run-out a Flushness Tolerancec Slot Width n Slot Depth t
Max. (Theor. Sharp) 2d Min. 1.75d Max. 0.5d Min. 0.45d Min. Max. 2pd Max. Max. Min. Max. 0.3d Min. 0.2d
BS 4183 - M1 2 1.75 0.5 0.45 0.1 e 0.5 .... 0.45 0.31 0.3 0.2
BS 4183 - M1.2 2.4 2.1 0.6 0.54 0.1 e 0.5 .... 0.5 0.36 0.36 0.24
BS 4183 - M1.4 2.8 2.45 0.7 0.63 0.1 e 0.6 .... 0.5 0.36 0.42 0.28
BS 4183 - M1.6 3.2 2.8 0.8 0.72 0.1 15 0.7 .... 0.6 0.46 0.48 0.32
BS 4183 - M2.0 4 3.5 1 0.9 0.1 16 0.8 .... 0.7 0.56 0.6 0.4
BS 4183 - M2.2 4.4 3.85 1.1 0.99 0.1 17 0.9 .... 0.8 0.66 0.66 0.44
BS 4183 - M2.5 5 4.38 1.25 1.12 0.1 18 0.9 0.1 0.8 0.66 0.75 0.5
BS 4183 - M3 6 5.25 1.5 1.35 0.1 19 1 0.12 1 0.86 0.9 0.6
BS 4183 - M3.5 7 6.1 1.75 1.57 0.2 20 1.2 0.13 1 0.86 1.05 0.7
BS 4183 - M4 8 7 2 1.8 0.2 22 1.4 0.15 1.2 1.06 1.2 0.8
BS 4183 - M4.5 9 7.85 2.25 2.03 0.2 24 1.5 0.17 1.2 1.06 1.35 0.9
BS 4183 - M5 10 8.75 2.5 2.25 0.2 25 1.6 0.19 1.51 1.26 1.5 1
BS 4183 - M6 12 10.5 3 2.7 0.25 28 2 0.23 1.91 1.66 1.8 1.2
BS 4183 - M8 16 14 4 3.6 0.4 34 2.5 0.29 2.31 2.06 2.4 1.6
BS 4183 - M10 20 17.5 5 4.5 0.4 40 3 0.37 2.81 2.56 3 2
BS 4183 - M12 24 21 6 5.4 0.6 46 3.5 0.44 3.31 3.06 3.6 2.4
BS 4183 - M14 28 24.5 7 6.3 0.6 52 4 0.52 3.31 3.06 4.2 2.8
BS 4183 - M16 32 28 8 7.2 0.6 58 4 0.6 4.37 4.07 4.8 3.2
BS 4183 - M18 36 31.5 9 8.1 0.6 64 5 0.67 4.37 4.07 5.4 3.6
BS 4183 - M20 40 35 10 9 0.8 70 5 0.75 5.37 5.07 6 4
  • a Nominal sizes shown in parentheses are non-preferred.
  • b See Radius Under the Head of Screws description in text.
  • c See 90-Degree Countersunk Head Screws description in text.
  • d See text following table in Lengths of Thread on Screws description in text.
  • e Threaded up to head.
  • All dimensions are given in millimeters. For dimensional notation, see diagram on page 1610. Recessed head screws are also standard and are available. For dimen- sions see British Standard.