This section is from the book "Cassell's Cyclopaedia Of Mechanics", by Paul N. Hasluck. Also available from Amazon: Cassell's Cyclopaedia Of Mechanics.
The following table gives the thickness of the bolt-heads and the widths of hexagon nuts in the Whitworth standard. The third, fifth, and seventh columns are to the nearest sixty-fourth of an inch: -
Thickness of Nut in In. | Thickness of Head in In. | Width of Nut across Flats in In. | Width of Nut across Corners in In. | |||
1/2 | •4375 | 7/16 | •9191 | 59/64 | 1.06 | 1 1/16 |
3/16 | • 4921 | 31/64 | 1.011 | 1 1/64 | 1.16 | 15/32 |
5/8 | •5468 | 35/64 | l.101 | 1 7/64 | 1.27 | 1 17/64 |
11/16 | .6015 | 19/32 | 1.2011 | 1 13/64 | 1 .38 | 1 3/8 |
3/4 | .6562 | 21/32 | 1.3012 | 1 19/64 | 15 | 1 1/2 |
13/16 | .7109 | 45/644 | 1.39 | 1 25/64 | 1.6 | 1 39/64 |
7/8 | •7656 | 49/64 | 1.4788 | 1 31/64 | 1.7 | 1 45/64 |
1 5/16 | •8203 | 1/1 5/6 | 1.5745 | 1 37/64 | 1.82 | 1 33/64 |
1 | •875 | 7/88 | 1.6701 | 1 43/64 | 1.95 | 1 33/64 |
1 1/8 | .9843 | 6/6 3/4 | 1.8605 | 1 55/64 | 2.15 | 2 5/64 |
1 1/4 | 1.0937 | 1 3/33 | 2.0483 | 2 3/64 | 2.36 | 2 23/64 |
1 3/4 | 1.2031 | 1 13/64 | 2.2146 | 2 7/32 | 2.55 | 2 35/64 |
1 1/2 | 1.3125 | 1 5/16 | 2.4131 | 2 13/32 | 278 | 2 23/32 |
1 5/8 | 1.421 | 1 27/64 | 2.5763 | 2 37/64 | 2.97 | 2 31/32 |
1 3/4 | 1.5312 | 1 17/32 | 2.7578 | 2 3/4 | 3.18 | 3 3/16 |
1 5/4 | 1..6406 | 1 31/64 | 3.0183 | 3 1/64 | 3.48 | 3 31/64 |
2 | 1.75 | 1 3/4 | 3.1492 | 35/32 | 363 | 3 5/8 |
The odd 1/16 -in. sizes given above are seldom used.
 
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