Buffer Speeds

U

unky_gumbi

Joined
Aug 28, 2009
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7,951
After not being able to achieve the level of finish I wanted I have decided that I need to set up a buffer. I am looking at a mandrel on pillow blocks and belt driving it with a some step pulleys. What I am interested in is what RPM should I be aiming to get for general blade buffing?

This is going to be yet another budget build, I can get the mandrel for just under $30 and comes with a 2"/2.5" step pulley, the motor will most likely be a 1/3hp 1725rmp reversible furnace motor. I haven't seen the mandrel in person yet but it looks like I can change the step pulley it comes with so I am thinking 3 or 4 speeds. Right now it looks like the major expense for this toll will be the pulleys, or the combination price of 4 or 5 buffing wheels
 
a 1/3 hp motor might not be enough to run a buffer. it will probably stall when you go to buffing a blade. i bet you can even stall the motor by grabbing the shaft as is. i tried a 1/3 hp motor with the paper wheels once and i was able to stall the motor buffing a small folder blade with a narrow edge.
 
It all depends on diameter of buffing wheel in relationship to motor rpm, so that you know your surface feet per minute. I have a Baldor 1 hp that runs at 1800 rpm and I use a 10"-12" buffer for stainless steel and when it gets down to about 6" I use it for handles. 1800 rpm X 31.4" circumference of a 10" buffer equals 4725 surface ft per minute and a little over half of that for the handle material. This works well for me using black, then green chrome, finishing off with white rouge. I'm in a hurry so I hope my math was correct. I'm sure I will be corrected if not:) This works well for me, hope it helps.
Jim
 
I would use a 1/2 to 3/4HP mtor. Also, blower fan motors aren't made for the torque loads of a buffer. Put a single pulley on the mandrel, and put the step pulley on the motor. Go for speeds of about 500,800,1200RPM for a 10" buff. With a 6" mandrel pulley and a 2"/3"/4" step pulley on a 1750 RPM motor you will get 530/875/1200 RPM at the buffer shaft. On a 10" buff that is 1300/2100/3150 SFM.
 
Can I suggest, you build a buffing add on that fits your grinder?

No motor expense
Perfect speed adjustment

Something like this, only with buffing arbour instead of a disc.



kmg_disc1.jpg
 
Well the motor was free so I will give it a try, it is of no real cost to me other than some wiring and a switch. Both of which I would have to buy any how if I bought a bigger motor. I don't doubt what I am being told, and I will budget for the 1/3hp to be too small and the need to pick up a bigger motor. If nothing else it gives me something to set everything up with. To be honest I am not even sure the motor that was dropped off to me is 1/3hp I didn't look:o it was really meant for my blower, but the feeling of frustration I got when I couldn't get the finish I was looking for on a knife got me thinking buffer on the cheap:p

Numbers, that is a cool set up, and I will be looking into it for a disc grinder, but I think the cost of the parts would be more than the Busy Bee mandrel I am looking at. the Busy Bee one is all of $30, crappy bearings, but it is double sided and I can alway replace the bearings in the future. I also think I would like to keep my buffer separate from my grinder to avoid contamination.



I went out and checked the motor this morning and it is only a 1/3hp 1725rpm motor. Lie I said I will give it a try as a buffer motor, but I think it will end up on the blower any how even if it does sort of work as a buffer motor
 
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