Thread Size | BSF Pitch tpi (Actual) | Hex Flats
(Max) | Head Height
(Max) | Bolt Thread Length (Min) |
1/4 | 26 | 0.445 | 0.176 | 0.750 |
5/16 | 22 | 0.525 | 0.218 | 0.875 |
3/8 | 20 | 0.600 | 0.260 | 1.000 |
7/16 | 18 | 0.710 | 0.302 | 1.125 |
1/2 | 16 | 0.820 | 0.343 | 1.250 |
9/16 | 16 | 0.920 | 0.375 | 1.375 |
5/8 | 14 | 1.010 | 0.417 | 1.500 |
3/4 | 12 | 1.200 | 0.500 | 1.750 |
7/8 | 11 | 1.300 | 0.583 | 2.000 |
1” | 10 | 1.480 | 0.666 | 2.250 |
1 1/8 | 9 | 1.670 | 0.750 | 2.500 |
1 ¼ | 9 | 1.860 | 0.830 | 2.750 |
1 3/8 | 8 | 2.050 | 0.920 | 3.00 |
1 ½ | 8 | 2.220 | 1.000 | 3.250 |
1 ¾ | 7 | 2.580 | 1.170 | 3.750 |
2” | 7 | 2.760 | 1.330 | 4.250 |
2 ½ | 6 | 3.550 | 1.670 | 5.250 |
3” | 5 | 4.180 | 2.000 | 6.250 |
3 ½ | 4.5 | 4.810 | 2.330 | 6.750 |
4” | 4.5 | 5.440 | 2.660 | 8.250 |
For lengths 5” to 8” add ¼”
to thread length above For lengths over 8” add ¾”
to thread length above
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These dimensions are for
use as guide purposes only
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