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forming taps

DGT

Plastic
Joined
May 15, 2017
I have a question concerning Whitworth treads, mainly on British motorcycles. Would forming taps be suitable to reshape the Whitworth tread to American standard? I'm talking aluminum cases and the like. I think that the tpi and dia. are the same in most instances, the big difference is thread shape. Thanks for any input.
 
Yes it will work, and IMHU is better than cutting the threads ** (see note below)............but BSW - coarse only interchange up to & inc 7/16 1/2 is different, as are some sizes above. BSF - fine and UNF do not play ball.

BS Cycle thread BS Cy is actually 60 deg and not 55deg WW form as many think, and AFAIK do not interchange with any unified threads.

** Be careful, some Brit bike alu castings are very crumbly and brittle AKA muckmetal .......... do not take kindly to being formed.

OVERALL IT IS A BODGE ...... If you want to do a proper job, helicoil the threads to take UN fastenings.
 
As much as the owners cuss stuff like this they likely prefer an original bike. I don't think this would be a selling point.
 
My idea behind getting away from the Whitworth tread is to go to socket head screws. Anyone who has worked on old Brit bikes knows the problems with Philips screws. Also I like the idea of being able to go to the hardware store and buying the screws that vibrated out on my last ride. I'm looking around to see what taps can be used and then I'll have to find a proper lube. I've got some junk aluminum cases that I can practice on. All part of the brit bike experience, I love it.
 
Yep.
Commando S. Not a Roadster. Peanut tank instead of the big Roadster tank. Only differance though.
Miss it.
Joe

I guessed as much Joe, ....you had to be a Norton nut to love one though, I never was a Norton man, but my mate, was, .big glitch, - he was next to, no! ;- worse than useless with the wrenches, ......and as for that abortion of a gear box? ...........it would have been quite good - if they'd managed to get all the shafts in line.

IMO Nortons never could build a parallel twin engine, .....their singles were GOOD , .but obviously should not have got married.

They made my 350 & 500 Triumph twins seem positively civilised and well made, :eek:

That isolastic (anti vibration) engine / swing arm mount, shim and set so it didn't vibrate too badly and the bloody thing cornered like a wardrobe on top of a blancmange, set it so it cornered and it shook yer bloody teeth out.

And they wonder why they went down the tubes, talk about lipstick on a pig.
 
My idea behind getting away from the Whitworth tread is to go to socket head screws. Anyone who has worked on old Brit bikes knows the problems with Philips screws. Also I like the idea of being able to go to the hardware store and buying the screws that vibrated out on my last ride. I'm looking around to see what taps can be used and then I'll have to find a proper lube. I've got some junk aluminum cases that I can practice on. All part of the brit bike experience, I love it.

What kind of Phillips head? Pan? Countersunk? If countersunk then you will have to counterbore most likely for the socket heads. Make sure you have enough metal there.
 
My idea behind getting away from the Whitworth tread is to go to socket head screws. Anyone who has worked on old Brit bikes knows the problems with Philips screws. Also I like the idea of being able to go to the hardware store and buying the screws that vibrated out on my last ride. I'm looking around to see what taps can be used and then I'll have to find a proper lube. I've got some junk aluminum cases that I can practice on. All part of the brit bike experience, I love it.

Well first of all, they are not phillips head, they are Posidrive, get the correct screwdriver and it will work a lot better. That is if some moron has not bodged them all up with a philips screwdriver. Get your whitworth socket head cap screws from Klempf's British parts. Dodge center Minnesota. 507 374 2222 I have known him since the early 70's when we worked at WIW cycle center in Minneapolis. He probably knows more about british bikes than any man alive and you talk to Mitch himself not some moron from India that just takes orders.
 








 
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