Spindle-length for cottered, single-chainring

[PedalPedantic]

I would just like to know what a typical length for a cottered spindle is for single chainring (Williams C34)
and fixed-gear. The bike is a 1959 Claud Butler, so nothing unusual. I am thinking 120-121mm. Is that correct?

 

[TheDoctor]

Moved to Vintage
[/Mod hat]

 

[Ming the Merciless]

Best thing to do is measure the existing.

 

[PedalPedantic]

Yes, as a matter-of-fact, you are correct. The Bayliss Wiley #15 spindle is what you need, and that is precisely 120mm long.