Hey there everyone. We use imperial and metric hardware in our bots for many reasons. Basically some things are only available in one format or the other or the cost is prohibitive in one format or the other. So for us it is no big deal to mix them.
I am working on some house bots for competition and have found myself lacking. I need to attach some MXL timing belt pulleys onto a 6mm shaft. I’m not interested in changing to another belt size as MXL fits the size and scope perfectly. I have found a good source for the aluminum pulley at econobelt.com. The imperial ones have set screws in them, but the metric ones do not. I’m not interested in futzing around with drilling and tapping. Even drilling out a smaller imperial size one doesn’t sound very exciting to me.
Does anyone know of a place that sells aluminum MXL timing belt pulleys in metric sizes with the set screws in them? I’m looking for 3mm and 4mm in 12 to 18 tooth, and 6mm around 32 tooth. My googlefoo is not working well lately. 
tia
I even have the catalog set they provide. Well yes they do have the metric parts with set screws. I ordered everything for my new 3kg sumo, and James antweight battlebot brushless motor retrofit. 8) Thanks for the nudge in the right direction.