I have an old 3 speed hub that looks exactly like the S-A 3 speed except it says "Schwinn Approved. Austria." Did a little reading about it on the net. It appears to be exactly the same as the S-A 3 spd. Wanted to put this on a mountain bike. The bike previously had a 21 speed derailler. However the axle is to short (146mm.) I have an S-A 63C (3spd/brake hub) with an axle of 152mm which will fit the bike frame. Don't want to use the 63C so does anyone know if I can use that axle from the 63C in the Schwinn hub? If not can I get a longer replacement axle for this hub?
Thanks in advance.

Ive bought S-A spares from https://www.sjscycles.co.uk/.
If its a steel frame, consider cold-setting to the new width.

So I've got the 5-3/4" axle. Apparently they do have a 6-1/4" axle as well (#hsa440.) This might work.
Isn't cold setting only widening the frame? As I mentioned the hub I want to use is to short, so I would need shorten the gap.

https://www.bikeforums.net/classic-vi...peed-hubs.html

Thanks for the info. I'm somewhat new to trying to build a wheel. I think I might end up putting the hub back together after servicing it. Then I'll try cold setting the frame. I can cold set reduce the gap (I was wrong.) 6mm shouldn't be to much...

Cold setting is the bending process. You can go either way, as needed.

I've bent steel frames inward to accommodate the shorter Sturmey-Archer axle. Worked just fine.

In case it's not clear from the above discussion, this only applies to steel -- cold setting an aluminum frame is discouraged.

Frame is an somewhat older Diamondback "Topanga." Not sure what the metal is, most likely steel, but I'll try taking a magnet to it. Might I ask how far you bent the frame to accommodate the S/A? I'm assuming about the same. Even a 6mm (1/4") to about 3/8" (I can't remember the 3/8" conversion from the top of my head right now, tired but it's not difficult) maximum should be enough, and the axle nuts will suck the hub in a bit more. I also never gave the spacing between the frame, I forgot it.
That's right 3/8th is 11mm.

In my case it was an old ten speed frame, so I assume that I squeezed it down from 120 to 114 mm, not a lot. For a long time, I just let the nuts compress the frame, but I guessed it would be easier to remove and replace the wheel when it was the correct spacing, so I nudged it.