Share Page
Email Facebook Twitter Google LinkedIn Tumblr Whatsapp Share

ASME B18.3.1M Metric Socket Head Cap Screws

ASME B18.3.1M Metric Socket Head Cap Screws

Dimensions of ASME B18.3.1M Metric Socket Head Cap Screws

Nominal Size and Thread Pitch Body Diameter, D Head Diameter, A Head Height, H Chamfer or Radius, S, Max Hexagon Socket Size, J, Nom. Spline Socket Size, M, Nom. Key Engagement, T, Min Transition Diameter, Ba, Max
Max Min Max Min Max Min
M1.6 x 0.35 1.60 1.46 3.00 2.87 1.60 1.52 0.16 1.5 1.829 0.80 2.0
M2 0.4 2.00 1.86 3.80 3.65 2.00 1.91 0.20 1.5 1.829 1.00 2.6
M2.5 x 0.45 2.50 2.36 4.50 4.33 2.50 2.40 0.25 2.0 2.438 1.25 3.1
M3 x 0.5 3.00 2.86 5.50 5.32 3.00 2.89 0.30 2.5 2.819 1.50 3.6
M4 x 0.7 4.00 3.82 7.00 6.80 4.00 3.88 0.40 3.0 3.378 2.00 4.7
M5 x 0.8 5.00 4.82 8.50 8.27 5.00 4.86 0.50 4.0 4.648 2.50 5.7
M6 x 1 6.00 5.82 10.00 9.74 6.00 5.85 0.60 5.0 5.486 3.00 6.8
M8 x 1.25 8.00 7.78 13.00 12.70 8.00 7.83 0.80 6.0 7.391 4.00 9.2
M10 x 1.5 10.00 9.78 16.00 15.67 10.00 9.81 1.00 8.0 -- 5.00 11.2
M12 x 1.75 12.00 11.73 18.00 17.63 12.00 11.79 1.20 10.0 -- 6.00 14.2
M14 x 2b 14.00 13.73 21.00 20.60 14.00 13.77 1.40 12.0 -- 7.00 16.2
M16 x 2 16.00 15.73 24.00 23.58 16.00 15.76 1.60 14.0 -- 8.00 18.2
M20 x 2.5 20.00 19.67 30.00 29.53 20.00 19.73 2.00 17.0 -- 10.00 22.4
M24 x 3 24.00 23.67 36.00 35.48 24.00 23.70 2.40 19.0 -- 12.00 26.4
M30 x 3.5 30.00 29.67 45.00 44.42 30.00 29.67 3.00 22.0 -- 15.00 33.4
M36 x 4 36.00 35.61 54.00 43.37 36.00 35.64 3.60 27.0 -- 18.00 39.4
M42 x 4.5 42.00 41.61 63.00 62.31 42.00 41.61 4.20 32.0 -- 21.00 45.6
M48 x 5 48.00 47.61 72.00 71.27 48.00 47.58 4.80 36.0 -- 24.00 52.6
  • bThe M14X2 size is not recommended for use in new designs.
  • All dimensions are in millimeters
  • LG is a grip length and LB is body length.
  • For additional manufacturing and acceptance specificatons, see ASME B18.3.1M-1986.