Stepper shaft size and pulley bore size problem

[Smiler]

Yes, Psiron, exactly that. Because payment was coming from outside the contiguous (so they won't send to Alaska or Hawaii for ex) US, they refused the order, must have so much business they can turn away the rest of the world. Maybe the reccession has had an effect by now and they might accept an order, worth a try I suppose. They wouldn't even let my wife's aunt in Canada order for me. luckily I found automation overstock in the US who had the profile rail I needed and cheaper too. If the designer is willing (and he seems a decent guy), that would be the way to go, either that or source metric equivalents in the UK, these guys are very good: Bearingboys they do the pulleys you are after and the belts.

BTW, for your pulleys, just treat them as gears so a 12 tooth small pulley driving a 72 tooth larger pulley would give a 6:1 drive reduction (72/12=6) so you just need to work out the ratios he is using and get the metric equivalent

Jeff.