While the deburring wheels did suffer some excessive wear from being used for grinding, it also turns out that these wheels just suck. They started coming apart on people during normal deburring operations. These were cheaper wheels than we had used in the past, but they were not a good deal: they were a third the price but lasted a quarter as long.
So I’ve replaced them both with new, proper Scotch brand deburring wheels. Just be aware that these are over $90 each! They are absolutely not for any grinding or polishing – not for extended use or substantial material removal. They are only for removing burrs on aluminum (and other soft metals) or light burrs on mild to medium steel. Heavy or large burrs on steel should probably be removed on the belt sander, or at least reduced there before using the deburring wheel.
Also, I’ve moved the second deburring wheel back into the annex for use with the lathe. That means the (infrequently used) wire brush wheel is also back there.