Belt grinder advices

[Frank S]

Grinders, grinders, and more grinders.
I guess that I've never found one with too much power.
the old blacksmith shop where I apprenticed had 3 old arbor grinders 1 had a little 3 Hp motor on it with 2" wide 14" inch diameter fine grit finishing wheels on it that was the one we used to sharpen small cultivator shears.
One had a 10 Hp motor not real high speed but 4" by 20" coarse wheels would remove metal by the pound
The last one had a 45 Hp 4 cylinder Wisconsin it had 2 belt driven arbors on it 1 was horizontal with a single 10 inch wide 20 inch diameter wire wheel the other arbor was vertical with a single 20 inch diameter cupped wheel. this was used for grinding shear blades
One of my tasks was to keep all of the wheels dressed and true. In today's society I would no more trust a 12 or 13 year old young man with a diamond wheel dresser on a 1/2 hp 6" grinder let alone have him anywhere near those monsters. but I used them almost daily.
I like the OP's idea for a 1 1/5 Hp 2800 RPM motor fora belt sander/ grinder I would probably go with a 3.5 or 4" diameter 8 grove serpentine pulley to a 1.5" or possibly 2" driven arbor to power the flat drive sanding belt pulley make it changeable from about 4" in diameter to 6" in diameter
1 1/5 Hp will be a little on the small side in my opinion for a belt wider than 4 inches though and nowhere near enough for a disc much larger than 8"
My Delta 12" disc & 6 by 48" belt sander had a 3 HP 2800 RPM motor with a 3.5" pulley and the arbor had a 2" pulley it did a fine job but could be bogged down