Cottered spindle diameters?
 

They're not all the same, right? I've got a French spindle here that fits my 70mm Raleigh BB and I can fit an English 10 speed crank on it but not a Raleigh 3 speed crank.
Are some 5/8" and some 16mm? Am I going nuts. Seems to me I used to know this. I'm getting old.

I, too, have noticed that some spindles don't fit some cranks. I think they're all the same in theory, but some parts are manufactured out of tolerance.

I have a cottered Nervar crankset that seems to require a smaller spindle diameter than the French cottered spindle I'm using with a Durax cottered crankset. Odd.

Neal

I had a Taiwan-made Raleigh from the 80's and a Nottingham crank arm I had would not fit over the Taiwan-made spindle although it would work the other way around. The difference was only a few thousands of an inch according to my dial callipers but it made all the difference in the world. Perhaps someone missed a decimal point when they converted the English measurements to Metric when they set up the Taiwan factory.

If I remember right it was only 3-4 thousands of an inch but it would just not go on. I wasn't going to mess around trying to mill it up so I just went to my LBS and they had an old used crank in their parts bin that did fit and only charged me $5 for.

Ben, is that the spindle you got from me, I never thought of checking the Dia as I didn't know there would be a difference, here is what I have on them. I have a few used and NOS cottered cranks laying around if you want to use that spindle, let me know.

ISO= 16mm Nominal or 15.9 Actual
English= 5/8" (15.88mm) Nominal or 15.75-15.80mm Actual
French= 16mm Nominal or 15.9 Actual
Italian= 16mm Nominal or 15.9mm Actual

Glenn

.1mm = 0.003937 inch

My Taiwan crank above must have been ISO while the Nottingham-made one was obviously very British. That explains the 4-5 thousandths difference I measured between the two.

Thanks Glenn. That explains a lot.

Yeah, it's that one. It fits the 10 speed crank that I'd planned on using with this bike when I bought it but now I'm thinking of using a Raleigh Heron crank instead. You don't have a 15.9 heron crank lying around, do you?
Where did you find that chart? I looked all over for that info.

Ben I will be honest, I don't know what a Heron crank looks like and if I do have one it would most likely have the 5/8" center. I got this info out of my Sutherland's manual. I have a few old Raleigh's out here that I didn't pull apart when I found those spindles, would you like me to.

Glenn

No, I just need to sit down with my favorite brand of abrasive and a beer and work this out. I just need to learn not to mix and match stuff so much.

Those cranks are HARD. I hope you aren't thinking of grinding down 4 thousandth of an inch off of one side. I think you will not only kill yourself trying but if you suceeded you are going to compromise the fitment/roundness which needs to be pretty darn exact for the cotter to hold it properly. If there are any high spots or wows in it you are going to have problems.

I'd take the crank to a machine shop and have them bore it out a little bit. They can keep it round. Either that or have the spindle turned down a little bit on a lathe. I'm not even sure doing it by hand is even possible. Like I said -HARD.

I had good luck at my LBS -they had a crank for $5. Maybe yours has a spindle.

Yeah, another spindle is a good idea, it's just an odd size and Glennford gave me a really nice one. I actually have a buddy who's sending me a Heron crank from the late 20s/early 30s that's much nicer than the late 70s thing that I have. When it gets here I'll see how it fits and then think about things some more.

Oh, Glenn, a Heron crank is the kind you find on old Raleighs that has the bird profile cut into it. And maybe I will hit you up for one more spindle but I want to see this new (old) crank that's coming first.
Thanks folks, nuther mystery solved.

Ben that is a Stronglight 123, if I remember correctly and my manual has it listed for a double crank, would the chain line even work with a three speed single ring attached to it. I know that is a very nice spindle and should be smooth as butter but you may have to compromise, whatcha building anyway.

Glenn

Ben, if you need to try a different spindle, let me know. I have a large stash.