Thread: Buffer /Grinder question...

Originally Posted by hornm

1/4 x diameter of wheel x rpm = sfmSmaller wheel = slowerHorn

Soon after I made my post I had a feeling I was wrong. Glad someone corrected me.

Surface feet per minute. Sorry. I just copied what I had in my notes without thinking about the abbreviations.

Horn

Originally Posted by hornm

Surface feet per minute. Sorry. I just copied what I had in my notes without thinking about the abbreviations.

Horn

Thanks Horn

The larger the Dia the faster the wheel passes the work. RPM does not change with wheel size.

(RPM * Dia)/4 = SFM roughly (order of operations)
or
RPM = (12*SFM)/3.14168*DIA so (3.1416*DIA*RPM)/12=SFM More accurate but the first is good enough

I think some of the guys use 4" buffs on the faster motors.

Jeff

I have a baldor that's 1725 rpms and I have one of the variable speed deltas. To be honest I don't think the 275 rpm is going to be that much of an issue. You certainly don't want a 3450 rpm but 2000 should be ok.

Another option it to get one of the belt driven pillow block type buffers and find yourself a slower 1/2 hp motor to run it. Ya the enclosed motor systems are nice but.... one of the nice things about a pillow block buffer is that you can control the speed by the motor you select and by pulley size. The math is pretty easy for figuring the speed by pulley size. IF you would be interested in this type set up I can show you how to do the math and you can probably get that buffer down to 1000 rpm if you want.

That being said, I really don't like the idea of sticking a sharp razor into a buffer. The buffer really is the most dangerous tool in my shop. I know knifemakers who have had sharp pointy things grabbed by the buffer and thrown into themselves. If you do decide to go that route please do be careful and don't let yourself ever get so comfortable with it that you let your guard down.