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blueprint (Structural) (OP)
11 Jan 02 23:20

I would like to know what standard bolt or screw size is associated with a 5/8" or 3/4" ring spanner.
ie. 5/8" ring spanner fits on nut(standard nut)what size would the bolt be. I dont want to go back to site to measure it.
I know it is not a 5/8 bolt.

diamondjim (Mechanical)
12 Jan 02 6:22
If you are talking about the dim. over
flats then the bolt would be
1/2 inch dia. if an unfinished bolt or a
7/16 dia. bolt if a finished
3/4 flat on bolt head.

For the 5/8 flat
7/16 dia. for unfinished bolt head or
3/8 dia. for finished bolt head

Nothing is ever simple.
MikeMilburn (Mechanical)
12 Jan 02 7:46
A very rough rule of thumb is the wrench size is 1 1/2 times the bolt size, ie, a 1/2" bolt-3/4" wrench, 1" bolt- 1 1/2" wrench. As I said, very rough rule ...Mike
clatford (Mechanical)
16 Jan 02 19:00
Hi Blueprint,

You might find some help on the following :

Hope it saves you a journey!


clatford (Mechanical)
24 Jan 02 4:27
Oh! what a tangled net.......!!!

Whitworth or British Standard Whitworth (BSW) nuts and bolts use the same spanners as do British Standard Fine (BSF).   BSF bolts have a smaller head ie 'across flats' dimension than Whitworth for the same bolt diameter, by one sixteenth in the spanner rating.


3/16 BSW fits 1/4 BSF
1/4  BSW fits 5/16 BSF
5/16 BSW fits 3/8 BSF       and so on.

In this way the British took engineering around the world!

Now we have metric sizes and nothing works at all!

Mike.   :)

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