I am thinking the ball bearings would be fine on regular shafting (3/4" cold rolled even?). Yes the balls don't make a ton of contact with the shaft, but there are lots of them, and the pressure isn't that high on a home made machine. It would last many years IMHO. Even with low friction the bearing will be quite tight, ie. no play at all. remember the balls just need to roll along. They actually roll thru the bearing and out the back into a tunnel built in to bring it back around to the front. They work slick (punn intended).
I would stay away from the plastic bearings.
Eric
__________________
I wish it wouldn't crash. |