Hexagon head bolts and screws

Hexagon head bolts and screws

Hexagon head bolts and screws

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
nomi
nal
size
D		 Number of
threads per
inch		 Diameter of
unthreaded por
tion of shank
B		 Width across flats
A		 Width
across
corners
C		 Diameter of
washer face
E		 Thickness
of head
F		 Radius
under head
R		 Split cotter pin holes, see Clause 11
Diameter
of hole		 Drill
sizes		 Maximum off-
centre distance
between centre
line of hole
and thread
B.S.W B.S.F Max. Min. Max. Min. Max. Max. Min. Max. Min. Max. Min. Max. Min.
in in in in in in in in in in in in in in mm in
¼ 20 26 0.2500 0.2465 0.445 0.438 0.51 0.428 0.418 0.176 0.166 0.025 0.015 0.075 0.070 1.80 0.006
⁵⁄₁₆ 18 22 0.3125 0.3090 0.525 0.518 0.61 0.508 0.498 0.218 0.208 0.025 0.015 0.075 0.070 1-80 0.006
⅜ 16 20 0.3750 0.3715 0.600 0.592 0.69 0.582 0.572 0.260 0.250 0.025 0.015 0.075 0.070 1-80 0.006
⁷⁄₁₆ 14 18 0.4375 0.4335 0.710 0.702 0.82 0.690 0.680 0.302 0.292 0.025 0.015 0.110 0.104 2-65 0.007
½ 12 16 0.5000 0.4060 0.820 0.812 0.95 0.800 0.790 0.343 0.333 0.025 0.015 0.110 0.104 0.65 0.007
⁹⁄₁₆ 12 16 0.5625 0.5585 0.920 0.912 1.06 0.900 0.890 0.375 0.365 0.045 0.020 0.143 0.136 3.50 0.008
⅝ 11 14 0.6250 0.6190 1.010 1.000 1.17 0.985 0.975 0.417 0.407 0.045 0.020 0.143 0.136 3.50 0.008
¾ 10 12 0.7500 0.7440 1.200 1.190 1.39 1.175 1.165 0.500 0.480 0.045 0.020 0.174 0.166 4.20 0.009
⅞ 9 11 0.8750 0.8670 1.300 1.288 1.50 1.273 1.263 0.583 0.563 0.065 0.040 0.174 0.166 4.20 0.009
1 8 10 1-0000 0.9920 1.480 1.468 1.71 1.453 1.443 0.666 0.636 0.095 0.060 0.208 0.199 5.10 0.010
1⅛ 7 9 1-1250 1-1170 1-670 1-640 1-93 1-620 1-610 0.750 0.710 0.095 0.060 0.208 0.199 5.10 0.010
1¼ 7 9 1.2500 1.2420 1.860 1.815 2.15 1.795 1.785 0.830 0.790 0.095 0.060 0.238 0.228 5.80 0.011
1⅜ -- 8 1.3750 1.3650 2.050 2.005 2.37 1.985 1.975 0.920 0.880 0.095 0.060 0.238 0.228 5.80 0.011
1½ 6 8 1.5000 1.4900 2.220 2.175 2.56 2.155 2.145 1.000 0.960 0.095 0.060 0.238 0.228 5.80 0.011
1¾ 5 7 1.7500 1.7400 2.580 2.520 2.98 2.495 2.485 1.170 1.110 0.095 0.060 0.271 0.261 6.60 0.012
2 4.5 7 2.0000 1.9900 2.760 2.700 3.19 2.675 2.665 1.330 1.270 0.095 0.060 0.333 0.323 8.20 0.015
Note standard with B.S.W. thread.
When bolts from ¼ in to 1 in nominal size 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 maximumn size.