BS 1083 Precision Hexagon Bolts

BS 1083 Precision Hexagon Bolts

                                                                                                                       
Nominal Size D Number of Threads per Inch Width Diameter of Washer Face G Radius Under Head R Diameter of Unthreaded Portion of Shank B Thickness
Across Flats A Across Corners C Head F
BSW BSF Max. Min. a Max. Max. Min. Max. Min. Max. Min. Max. Min.
BS 1083 - 1⁄4 20 26 0.445 0.438 0.51 0.428 0.418 0.025 0.015 0.25 0.247 0.176 0.166
BS 1083 - 5⁄16 18 22 0.525 0.518 0.61 0.508 0.498 0.025 0.015 0.313 0.309 0.218 0.208
BS 1083 - 3⁄8 16 20 0.6 0.592 0.69 0.582 0.572 0.025 0.015 0.375 0.372 0.26 0.25
BS 1083 - 7⁄16 14 18 0.71 0.702 0.82 0.69 0.68 0.025 0.015 0.438 0.434 0.302 0.292
BS 1083 - 1⁄2 12 16 0.82 0.812 0.95 0.8 0.79 0.025 0.015 0.5 0.496 0.343 0.333
BS 1083 - 9⁄16 12 16 0.92 0.912 1.06 0.9 0.89 0.045 0.02 0.563 0.559 0.375 0.365
BS 1083 - 5⁄8 11 14 1.01 1 1.17 0.985 0.975 0.045 0.02 0.625 0.619 0.417 0.407
BS 1083 - 3⁄4 10 12 1.2 1.19 1.39 1.175 1.165 0.045 0.02 0.75 0.744 0.5 0.48
BS 1083 - 7⁄8 9 11 1.3 1.288 1.5 1.273 1.263 0.065 0.04 0.875 0.867 0.583 0.563
BS 1083 - 1 8 10 1.48 1.468 1.71 1.453 1.443 0.095 0.06 1 0.992 0.666 0.636
BS 1083 - 11⁄8 7 9 1.67 1.64 1.93 1.62 1.61 0.095 0.06 1.125 1.117 0.75 0.71
BS 1083 - 11⁄4 7 9 1.86 1.815 2.15 1.795 1.785 0.095 0.06 1.25 1.242 0.83 0.79
BS 1083 - 13⁄8b ... 8 2.05 2.005 2.37 1.985 1.975 0.095 0.06 1.375 1.365 0.92 0.88
BS 1083 - 11⁄2 6 8 2.22 2.175 2.56 2.155 2.145 0.095 0.06 1.5 1.49 1 0.96
BS 1083 - 13⁄4 5 7 2.58 2.52 2.98 2.495 2.485 0.095 0.06 1.75 1.74 1.17 1.11
BS 1083 - 2 5 7 2.76 2.7 3.19 2.675 2.665 0.095 0.06 2 1.99 1.33 1.27
  • a When bolts from 1⁄4 to 1 inch are hot forged, the tolerance on the width across flats shall be two and a half times the tolerance shown in the table and shall be unilaterally minus from maximum size. For dimensional notation, see diagram on page 1571.
  • b Noted standard with BSW thread.
  • All dimensions in inches except where otherwise noted.