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BS 1981 Pan Head Screws

BS 1981 Pan Head Screws

Nom.Size of Screw Basic Dia. D Threads per Inch Dia. of Head A Depth of Head B Width of Slot H Depth of Slot J
UNC UNF Max. Min. Max. Min. Max. Min.
BS 1981 - 4 0.112 40 ... 0.219 0.205 0.068 0.058 0.039 0.031 0.036
BS 1981 - 6 0.138 32 ... 0.27 0.256 0.082 0.072 0.048 0.039 0.044
BS 1981 - 8 0.164 32 ... 0.322 0.306 0.096 0.085 0.054 0.045 0.051
BS 1981 - 10 0.19 24 c 32 0.373 0.357 0.11 0.099 0.06 0.05 0.059
BS 1981 - 1⁄4 0.25 20 28 0.492 0.473 d 0.144 0.13 0.075 0.064 0.079
BS 1981 - 5⁄16 0.3125 18 24 0.615 0.594 0.178 0.162 0.084 0.072 0.101
BS 1981 - 3⁄8 0.375 16 24 0.74 0.716 0.212 0.195 0.094 0.081 0.122
BS 1981 - 7⁄16 0.4375 14 20 0.863 0.838 0.247 0.227 0.094 0.081 0.133
BS 1981 - 1⁄2 0.5 13 20 0.987 0.958 0.281 0.26 0.106 0.091 0.152
BS 1981 - 5⁄8 0.625 11 18 1.125 1.09 0.35 0.325 0.133 0.116 0.189
BS 1981 - 3⁄4 0.75 10 16 1.25 1.209 0.419 0.39 0.149 0.131 0.226
  • a All dimensions, except J, given for the No. 4 to 38-inch sizes, incl., also apply to all the 80° Raised
  • Countersunk Head Screws given in the Standard.
  • b Also available with recessed heads.
  • c Non-preferred.
  • d By arrangement may also be 0.468.