My BC came yesterday. The instructions recommend that the mill not be powered by a motor. If the rpms are 500 or less, what would be the problem with motorizing vs. using a hand drill?
I have a couple of motors with rpms of 1725. If I put a 2 inch pulley on the motor and a 10 in pulley on the mill spindle, I calculated the rpm of the mill will be right around 500 rpms.
The reason for "no motor" is that a constant pull in one direction will wear the brass bushing on the BC drive shaft into an egg-shape, and the spacing between rollers will get all messed up.
If I'm grinding into a 5gal bucket, I put another 5gal bucket next to it and lay the drill on top of it. That way the weight of the drill will not be pulling down on the BC shaft. I use a DeWalt 3/8" Hammer Drill which is a pretty heavy unit.
I have a 19:1 gear reduction unit that I was considering
using with a 1725 rpm motor. The reduction unit output would be direct-coupled to the BC - so no sideways pull. The problem is that I would have to build a stand to mount all the components, and this would take up a bunch of garage space, be harder to clean, move grain buckets, etc.
Since I only brew once or twice a month, a good 3/8" electric drill works fine, and lets me put everything back on the shelf until next time.
BTW, if you're going to go out and buy a 3/8 drill, get a good hammer drill. It's only a few bucks more than a regular one, and eventually one day you'll need to drill a hole in concrete.