Cottered Crank

[funk2monk]

Having now had the Claud Butler painted I'm slowly re-assembling the bike. I've re-greased and put the original bottom bracket back in which seems to run smoothly.

However, the Williams crankset I've thought about using doesn't fit? The bottom bracket measures 15.8mm whilst the internal of the Williams is 15.6mm.

I have a 'spare' crankset which is slides straight onto the crank but its not complete and in poor condition.

Is there a difference in crank diameters as I've been looking at sourcing a replacement crankset but none of these gives a dimension so I assume they all should be interchangeable. I'm aware the length of the crank is different for single or dual chain rings, this is a single chain wheel.
The bike is a 1949 Claud Butler Closed Circuit model.

Thanks in advance.

 

[tyred]

Very strange. I've never measured any of them but I've swapped cottered cranks around various bikes over the years without ever encountering a problem.

The only thing I can think of is that one might be Continental (it will take a 9mm cotter pin. British spec were 3/8"). Measure the diameter of the cotter pin holes to see if they match.

 

[midlife]

Not sure why but 15.8mm rings a bell as being the standard diameter......

 

[Poacher]

Sheldon Brown (has anyone suggested sanctification?) reckons that "French cottered spindles have a diameter of 15.5 mm (0.610") and most others, 0.625" (5/8")."
0.625 * 2.54 = 1.5875
Did Williams make cranksets for the French market, and have you inadvertently bought one of those?
Must confess. I've always thought that cottered spindles were a universal standard, but I sit corrected.

 

[Once a Wheeler]

A decent bike shop should be able to ream out the crank with no problem: the UK/continental adaptation used to be a standard procedure. Otherwise, change the axle. Reaming was often a free-of-charge service to regular customers,

 

[Dogtrousers]

Just goes to show that as much as we complain about the multiplicity of BB standards these days, it's not entirely a new thing.