It's not just the diameter, but the width of the buff or any wheel for that matter that causes extra load on the motor. Especially with a loose buff like that, a soft hand and that is an accident waiting to happen. I'd go check out the belt/disk sanders, more useful than multiple bench grinders. Sounds like a fun place to shop.
not to hi-jac but l have the big old orange HF buffer, the guy assured me it was fine, and he hardly used it.
Call me crazy, but there have been times l have trusted a guy from e bay or craigs list gotton a good feeling about him, and brought something sight un seen.
Case in point the buffer, and my cicra 1947 unisaw.
Its .again, the big old orange buffer HF sold, don't think they sell that one any more, l have heard good reviews about it.
and It came with I think it;s HF too, a grinder stand...................$30.00.
The uni was sweet. no problems, and the grinder is (buffer) is sweet l am sure, (Positive thoughts.....)........................ but the seller wasn't home when I picked it up, I was gonna ask his wife to let me plug it in, but the plug was messed up, I called the guy, (I was picking it up from his back yard) and (no actually, sorry , its the wire was cut in two) asked him Whats up w/the wire, but it had been tucked in the stand post, he said he wasn't sure, and assured me it worked, he just never used it like he thought he would. (he offered to send my some back I said its all good.
I really need to get that tested, but still running power back there, (the "overflow area" my buddy calls it,) and have to fix the wire still.
can't stay down there as long as I used to, and other projects were first in line.
To wit, Sweetest young girl in the world, now if she's really like this all the time, and not just with her patients, if i could go in a time machine (just me now, not her.......LOL) I would Pester her till she agreed and Marry her.........................LOL
But anyways, no time machines that l know of yet,
(shut up anthony, .....OK).................................
anyways she is a student from morgantown doing an internship at the PT dept here in the hospital.Really really nice girl though, but Friday is her last day.
I am making a country style wall shelf like you see at the flea markets, made of pine, with the roughly cut out heart, but using oak or walnut, not sure yet, but I make them furniture quality. I already ran my mouth to her boss, and said tot not tell Jacki, so I will look like a B/S'r if I don't come through. wow, for somebody that says he hates to type, this got long.
I hate it I tell you, I contend I Hate IT!!!!!

if you still reading and didn't say STFU yet,
thanks,