I have been thinking about building something like this myself instead of a full belt grinder project, but this is such a quality product at a reasonable price point that it became a no-brainer versus designing and troubleshooting my own build up front, which I'd probably run into with cheap import competitors to this as well
We found that having a large wheel with a hollow in the wheel (bolts only on one side, and that side to the motor) allowed us to quickly process parts, even with radiuses smaller than the wheel.