Belt grinder advices

[wizard69]

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

The amount of power you need varies with what you are doing. In the case of the original poster I'm not sure 1.5 HP will be enough. Those long wide belts can grind with an incredible hunger, so I would be concerned that 1.5 HP isn't enough to get the full monty so to speak out of the belt. Of course if you are doing fine finishing work on a knife or something you don't need that much power.