"Earlier this year I learned that my Ryobi bench grinder has an awful design flaw: The shields on the grinding wheels have too wide of a gap between the "shield" and the wheel - wide enough to suck your finger in by friction when the wheel is spinning. It happened to me and cut a nice wedge out of my fingertip, like the "cross-sectional diagrams" of planets and stars you might see in an issue of Astronomy Magazine. My finger healed completely, but Ryobi has not responded to my gentle prods to redesign the covers. Basically, the outer protective covers should provide clearance at the center [axle] for the nuts and washers that hold the wheels onto the shaft and after that, should be as close as practical (maybe 0.25 inch max) to the side surface of the grinding wheels. Anyone who designs it any other way has had too much design school and apparently ZERO time in the workshop."
Bench Grinder Has a Finger-Eating Gap
Retired Engineer Alan Falk spends lots of time in his workshop. Recently, he spent some unwelcome time in the ER: