Here's an idea I've been working on for some time now. It is based on an alum. thin wall tube held together by four 1/4-20 threaded rods grooved to fit up in a 2x2x1 bliock at each end carrying the bearings. One end has the collet and the other a sheave. I also think it could be water cooled by adding some fittings and silicone gasketing, or just filled with oil. Any comments or ideas to improve it?