Anyone running a 7inch drive wheel direct drive 2HP

JawJacker

Well-Known Member
Thinking of ordering the 7 inch drive wheel, but the torque with @2hp 1740 motor might be to weak
at low speeds. Any input thanks
 
Are we talking a VFD setup, or a single speed?

Either way I think SFPM (surface feet per minute) would be way faster then I'd personally, want with a 7" drive wheel.

On my old Square Wheel (my first "real" grinder) which came with a 10" drive wheel, on a 1725rpm motor, if you made even a slight bobble with a heavy grit belt, it would almost cut a blade in half.....and nearly always wreck it beyond repair. With finer grit belts the heat build up was astronomical too. As soon as I knew enough, and before they were ever available commercially, I had a 7 1/4" drive wheel custom made for that machine.... but even with that it was still too fast. (7 1/4" was the smallest I could use without having to extensively modify/built a whole new tooling arm....and at that time in my career, my skills were simply not up to the task).

All that being said, if it's a single speed machine, I'd go no larger then a 6" drive wheel, and if it's a VFD machine, no larger then a 4" drive wheel. The reasons I say that is because I can always grind a little more off, but if I grind too much, I can never put it back. In addition, heat build up during finish grinding, from finer grit belts running too fast, can be a very serious/difficult problem to overcome.

I'd much rather have/work on a grinder that runs a bit slower then I'd like, versus one that runs too fast. The only thing a slower grinder might cost you is a bit more grinding time.....while a machine that runs too fast multiplies problems exponentially.
 
Last edited:
I think Ed pretty much covered it, but was there a specific reason you were looking at a 7" wheel? What kind of grinder?
 
AR, I built my own grinder w/VFD being able to slow a 7 down or crank it up when I need it, thats all This week Ill get time to see how my 4 inch wheel works should be fine.
 
I realized you had recently built a grinder just after I posted. Personally, I have a 5" drive on my home built grinder with a VFD, and it goes as slow or as fast as I need it to. I use a 4" on my NWGS (3 step pulley, 1750RPM motor) and I rarely go above the middle speed on it, though anymore that grinder is more/less just my deburring machine.
 
I went the opposite direction with my wilmont LB1000. I found a 3" drive wheel and a 3 phase 800 rpm 1hp Leeson motor. As Ed pointed out, low speed grinding may take longer, but it is impossible to put steel back on your blade.
 
I think it's funny that you can jump all over the Internet and get a thousand 'right' answers to your questions, and each and every one of them conflicts with the other. :biggrin:

There is no such thing as too much speed on a variable speed grinder.

Wellllll....... that's assuming your machine is relatively well balanced. Then again, you could always slap a seat on that bad boy and ride it around the shop while you grind. :D

I am tempted to call Norton up and ask them at what SF/M the grit would simply fly off the belt as soon as I flipped the ON switch. :biggrin:
 
Back
Top