Re: 15 tooth + double sprockets
 

On the output shaft for the transmission I fail to see the issue with simply stacking two hubbed sprockets, this may require you to face them (to get the proper spacing) but this is what AM does in the AM-Shifters.

Look at the output sprockets as shown on the drawing below:
http://files.andymark.com/amshifter-asm.pdf

McMaster has a large selection of standard #35 sprockets, however you will need to broach the keyway/hex yourself.

Re: 15 tooth + double sprockets
 

Oh, you're right, I read that backwards. durpty durp.

The 22-tooth sprocket "doesn't fit" any of the plaction wheels because the plaction wheels have a built-in hub (same size and design, no matter the wheel size) that offsets the sprocket from the wheel. The diameter of that hub is too large when you use a 22-tooth sprocket because the chain walls rest on the hub instead of the rollers resting in the troughs between teeth, which can lead to jumped chain and inconsistent driving. AndyMark sells spacers and hubs with a diameter small enough for the 22-tooth sprocket, but there is also enough material in the wheel for you to turn down the built-in hub to a usable diameter with your handy-dandy lathe.

Re: 15 tooth + double sprockets
 

Justin beat me to the reply, but I totally agree with him.

I am failing to see why a double sprocket is necessary.

-Brando

Re: 15 tooth + double sprockets
 

what is the purpose of bolting together two sprockets ?

if you need two sprockets, then put two singles on the shaft.

the main advantage of the AM part is it reduces a ton of weight relative to the older method of installing two steel single sprockets.

Re: 15 tooth + double sprockets
 

Long ago in the dark days of pre kitbot FIRST we would buy ANSI triple roller chain sprockets and turn off the middle set of teeth on the lathe to solve this issue. Not sure if this is helpful but I know we still have a buck of these kicking around the shop.

Re: 15 tooth + double sprockets
 

I guess we'll have to try that. Thanks! I've no experience in this, however our mechanical team should know.