Originally Posted by Phil Russell
Very interesting observation that suddenly had me thinking.. there was a close relationship between BSA cycle threads and their gun threads. The standard BSA bottom bracket cycle thread was / is 24tpi. Are the BSA Standard end blocks 24tpi? It would be nice (in an old fashioned way) if they are and the Standard cylinder id was also the same size as a cycle BB shell. Maybe I should take time out to rummage amidst the old cycle bits in the box in the shed.
Note that Raleigh old threads were 26tpi but they changed over to the accepted standard of 24tpi many many years ago.
Cheers, Phil
Hi Phil
I measured the threads at 20TPI this afternoon.
Unfortunately screwing the trigger block into a spare Standard cylinder and dropping it into a Mercury stock is as far as I've got, but it all looks like a very doable project when I get time.
The only foreseeable problem would be the piston as the Standard piston rod won't latch into the Airsporter/Mercury top sear.
Now the Standard cylinder is about an inch longer than the Airsporter cylinder so the obvious piston to use would be an Airsporter one with a nose extension.
Alternatively a custom piston could be machined to give a longstroked gun.
Having bought the standard cylinder a while ago I have now accumulated enough parts (except for piston) from the good folks of the BBS to build a complete gun, but the challenge of building something different is drawing me in.
Decisions, decisions.
All the best Mick
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