I bought a ton of these to use as dials, like 20-30 each in 27, 28, 29, 38, and 40mm, which should cover any build I have planned in the forseeable future.
I 3D printed a jig to drill a hole in the center, and use them to practice techniques for making dials...Waterslide decals, laser etching, pad printing, different finishes and sealers, etc, even luming. If one turns out well, I can solder on dial feet and build up a watch. If it's botched horribly, I can clean it off and start again. I don't think my efforts have any legit sources of dials or sincere and experienced hobbysists sweating just yet, but progress is made with every one. They're .5mm each, so about the right thickness, or could be stacked up for the thicker 1-1.5mm dials.
For the cost of one dial, you can get enough of these to keep you busy for a lifetime.
