Viking Trackmaster bb

I've just aquired a '60's Viking Trackmaster without a bottom bracket. Does anyone know of a way to calculate the required spindle length for what is to be a cottered bb/ crankset?
The bb shell width is 68mm (with 24 tpi). Any help would be appreciated as to what I might need to look for.

i strongly recommend you not to use cottered crap on a fixed gear. no offence but from my experience cottered cranks are just rubish in fixed applications.

Are you in London? I've got an old cottered spindle you can use as a guide. It's about 130mm.

I wouldn't recommend cottered either, I found them to be an absolute nightmare

• 1 to anti-cottered. that is a really nice aquisition though.
  

Thanks for the replies. Yep, I know cottered can be a real pain. I've installed a cottered crank before and it worked ok after a few trial and error sessions + hammer. But, it was pretty fiddly and time consuming. I'm an old geezer though and really like those old timey chain rings and wanted to restore the bike to something like it's original.

@goodhead Cheers, I'm in London though I think I might have located some cottered axles/spindles. (If they turn out to be no good I might try and PM you if that's OK).

No probs Blockhead. PM me if you want the spare spindle. It's no real use as a permanent solution as it's too pitted, but it would give you an idea of what you may need as a replacement length.

Have you seen this?

http://www.sjscycles.co.uk/product-Unbranded-Cottered-Kinex-Sealed-Bottom-Bracket-136-mm-6861.htm

I'm doing something similar to be set up as singlespeed. It's a bit too long but I'm going to use spacers to push out the freewheel.

Yeah thanks, saw that and thought 'too long' but maybe... this lot do old bb stuff too.. http://www.cyclesofyesteryear.com/cycleshop/sparepart.htm