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  #1  
Old 04-09-20, 21:32
Harry Moon Harry Moon is offline
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Default Mystery socket sizes?

I picked up a set of 1/2 drive sockets yesterday, vintage and i cleaned them up and sorted them for my mechanic displays.
So I'm sorting these and can't understand the sizes. Made in USA so I didn't write them off as some eccentric (but perfectly logical, no offence) British thing
As marked and then measured and tried on various nuts and bolts.
marked 1 1/16 = 1 5/16
1 5/8 = 1 1/4
9/16 = 1"
1/2 = 15/16
5/16 = 5/8
3/16 = 15/32
1/4 = 17/32

Any explanation?
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  #2  
Old 04-09-20, 23:39
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Richard Farrant Richard Farrant is online now
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Quote:
Originally Posted by Harry Moon View Post
I picked up a set of 1/2 drive sockets yesterday, vintage and i cleaned them up and sorted them for my mechanic displays.
So I'm sorting these and can't understand the sizes. Made in USA so I didn't write them off as some eccentric (but perfectly logical, no offence) British thing
As marked and then measured and tried on various nuts and bolts.
marked 1 1/16 = 1 5/16
1 5/8 = 1 1/4
9/16 = 1"
1/2 = 15/16
5/16 = 5/8
3/16 = 15/32
1/4 = 17/32

Any explanation?
British Standard Whitworth ! I have some large 3/4" drive sockets from wartime period, made in USA, think they are Snap-on
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  #3  
Old 05-09-20, 19:33
Harry Moon Harry Moon is offline
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Default Thank you Peter

So, woulkd they be of any use to any particular vehicle? Free to a good home. Centurian?
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Old 05-09-20, 20:12
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So, woulkd they be of any use to any particular vehicle? Free to a good home. Centurian?
Hi Harry,
I guess a Centurion was made with BSF/BSW threads, as it dates from the 1940's and most British vehicles were using those threads into the 50's and 60's.

regards, Richard
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Old 08-09-20, 23:34
motto motto is offline
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As I understand it the British marked their spanner/socket sizes based on the shank/thread diameter of the bolt, not the distance across the flats (A/F)
I believe that the distance across the flats was arrived at by applying a ratio to the bolt/shank/thread diameter which usually ended up being an odd sort of in between measurement for the distance across the flats.
The Americans went the simpler route and rounded head size to the nearest 1/16"( mostly) and marked their tooling accordingly.

David
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Old 09-09-20, 00:44
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Quote:
Originally Posted by motto View Post
As I understand it the British marked their spanner/socket sizes based on the shank/thread diameter of the bolt, not the distance across the flats (A/F)
I believe that the distance across the flats was arrived at by applying a ratio to the bolt/shank/thread diameter which usually ended up being an odd sort of in between measurement for the distance across the flats.
The Americans went the simpler route and rounded head size to the nearest 1/16"( mostly) and marked their tooling accordingly.

David
Hi David,
I think that was correct pre-WW2, but to save metal the hex head and nut was reduced, so a 1/4" BSF or BS Whit bolt needs a 3/16" Whit spanner, 5/16" bolt needs a 1/4" Whit spanner and so one.

To go slightly off course, I get truck drivers coming into my workshop asking if I have a 10mm bolt, when I question them, it turns out they want a 6mm bolt, they go by the spanner size. Same used to happen with Unified and BS.

regards, Richard
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  #7  
Old 09-09-20, 08:49
Matthew P Matthew P is offline
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Quote:
Originally Posted by Richard Farrant View Post
Hi Harry,
I guess a Centurion was made with BSF/BSW threads, as it dates from the 1940's and most British vehicles were using those threads into the 50's and 60's.

regards, Richard
I would think US made BS tools would have a niche but desiring following. Just as there are those who collect British made US pattern field gear and US made British Lend-lease uniform bits.

Matt
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