Used brake discs make great bases for shop stands
The best and cheapest bases for workshop support stands I have found are scrap vehicle brake discs. They come in a range of sizes and weights, and have threaded holes for mounting the upright. Shops that service brakes discard piles of them and usually you can get them for free. I got mine just by stopping in and asking. I’ve used a larger disc for a floor-standing light and a smaller one for a benchtop version of the same thing. A large disc could be used as a base for a workshop seat, and an even larger and heavier one as a base for a grinder stand, for example, taking up minimal floor space.
—Bruce Dudman, Hobart, Tasmania, Australia