Crank shaft thread
Posted: Sun Sep 20, 2020 6:17 pm
What size is the screw thread in the crank to hold the flywheel on please.
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Crank shaft thread
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Re: Crank shaft thread
Posted: Sun Sep 20, 2020 6:22 pm
5/8" x 16tpi Whitworth form
Re: Crank shaft thread
Posted: Sun Sep 20, 2020 6:22 pm
According to the Guessworks site, it is 5/8" 16 TPI
http://www.guess-works.com/Shop/Parts/d ... htm?id=494
http://www.guess-works.com/Shop/Parts/d ... htm?id=494
Re: Crank shaft thread
Posted: Sun Sep 20, 2020 7:06 pm
Thanks - if anyone has one, can you confirm the o/d of the tap over the cutting edges.
Re: Crank shaft thread
Posted: Sun Sep 20, 2020 7:22 pm
Re: Crank shaft thread
Posted: Sun Sep 20, 2020 7:43 pm
So, that would make it a 16-16 tap???? 
Re: Crank shaft thread
Posted: Sun Sep 20, 2020 7:51 pm
Its 5/8 x 16tpi whit form .
It's a special non standard thread size
It's a special non standard thread size
Re: Crank shaft thread
Posted: Sun Sep 20, 2020 8:33 pm
Easily confused with a 5/8-16 SAE tap (more common here in USA), but that has a 60° angle thread form, so will under-cut the 55° of the Whitworth form. Blue loctite is your friend if someone else has already used an SAE tap...
Re: Crank shaft thread
Posted: Sun Sep 20, 2020 8:44 pm
I have taps available in my facebook shop if anyone needs one.
Re: Crank shaft thread
Posted: Mon Sep 21, 2020 8:03 am
Does that make it the same size as the bypass hose spigot in the head ?
Re: Crank shaft thread
Posted: Mon Sep 21, 2020 8:43 am
Yes - both ends of the crank and the bypass spigot are all this thread.
Re: Crank shaft thread
Posted: Mon Sep 21, 2020 9:42 am
Great - its worth buying one then.