John in NM
I've had lowly 1/3 hp grinders rip a work piece right out of my hands and throw it across the room when using a wire wheel or loose buffing wheel. I even once learned the hard way that the <1/4" guideline for tool rests and abrasives is there for a reason - never believed it until I saw it.

So I would say that while a larger machine like a lathe is more dangerous, even a small bench grinder is plenty dangerous on its own (which is part of the reason I like the hand crank buffer I use). Like the drill press, a buffer does not strike us as a horribly dangerous tool as a table saw often does - and we get complacent. I've been surprised and occasionally bitten by my drill press a lot more often than any other machine.