Whitworth Question

[Roger]

The crankshaft thread was much beloved by Austin. It appeared on Austin Seven crankshaft and half-shafts long before the A-type.
I have read that it was originally an Admiralty specification.

 

[JPSmit]

OK sorry I asked this wrong - if you go to the (kijiji) ad it is selling wrenches and sockets - I thought the different bolt head sizes were metric/ Imperial (American) and Whitworth.

Aren't the head dimensions of BSF and BSW threads the same as any other imperial bolt size? IE a 7/16 bolt uses a 7/16 wrench regardless of thread size?

 

[Roger]

American wrench sizes are measured Across Flats. A 1/4 in bolt has a 7/16 head, typically, a 5/16 has a 1/2 inch.
BS wrenches (spanners) are marked with the thread size, and the heads are not the same as SAE sizes.

 

[TR3driver]

There's a nice chart at https://www.samstagsales.com/whitworth_table.htm that gives the AF sizes for various British spanners.