hello,
I'm trying to mount a sprocket with a square hole (from the vex tank tread kit) on a motor with a round shaft (from robot marketplace). Does anyone know how I might go about doing this?
The motor shaft is smaller than the hole... so an adapter of some sort (premade or homebrew) should be able to work
thanks so much for your time 
hoping to hear back soon!
Glue?
Though it will probably break between the glue and shaft eventually. It could help to roughen up the shaft with coarse sandpaper before gluing.
the shaft has a 'knurled surface' (according to robotmarketplace) upon inspection... it's kind of like sandpaper... in any case, glue should adhere to it.
my issue is that the shaft is smaller than the hole it needs to be adhered to. and a different shape
my issue is that the shaft is smaller than the hole it needs to be adhered to. and a different shape
I got that part, the glue would have to act as a filler too, which is why it would be weaker.
I had a glue several years ago called "Liquid Steel" or something like that, it was a thick paste that came in a big tube and was very strong for metal on metal bonds. I wonder if something like that still exists. The gear part looks like plastic, but even so, that part is square so you wouldn't have to worry about that part of the glue bond breaking.
Oracle, are you thinking of J-B Weld : http://jbweld.net/products/jbweld.php
It is a high temperature epoxy and is quite expensive.
A good quality 30 minute epoxy should do just as well. Clean both parts with alcohol to remove any dirt or oil and mix the epoxy well before bonding.
If you use epoxy as a filler you'll want to make absolutely sure the parts are as precisely centered as possible.
hey guys... thanks so much for the help... I tried out lots of different tubing to try to fill some of the space (so it wouldn't be just epoxy) and found some brass tubing that fits almost perfectly.
I'll get some 30 minute epoxy and use it to fill the remainder of the space.
Thanks so much