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No. 5 Filler Thread
- Thread starter adammack
- Start date
I have filler plug for No5 & N0 23 grenades listed as 7/16" x 20 BSW threads. Check this is correct before you make any plugs.
I just checked and 7/16" BSW is 14 threads. SO I AM WRONG or it is a custom grenade thread.
Maybe try 7/16" UNF which is 20 threads. I will need to check this tomorrow. Whitworth is 55 and UNF is 60 degrees so it may remove metal but still fit??
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king ratgre
Active Member
7/16 BSC british standard cycle thread
That's interesting. A friend of mine who is an engineer said the Mills threads were BSC when he measured them. Is there much of a difference BSW/BSC ? I've got taps and dies for the 7/16 in BSW and they are a match.
7/16" BSW is 14 threads per inch. The No5 filler hole is 20 threads per inch.
Here is the thread sizes for BSC which is 26 tpi so wrong size for filling plugs.
British brass threads are 55 degrees so differ from BSC which is 60 degrees.
Check the common 7/16" UNF as I suggested as taps and dies are common, or cut on a lathe to fit.
Here is the thread sizes for BSC which is 26 tpi so wrong size for filling plugs.
British brass threads are 55 degrees so differ from BSC which is 60 degrees.
Check the common 7/16" UNF as I suggested as taps and dies are common, or cut on a lathe to fit.
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I have found Mills used UNF on some of his prototypes.
king ratgre
Active Member
oops my bad