Bench Grinder Burnisher Nightmare

[megganpowell]

I've tried both a Ryobi and a WEN bench grinder to try and make a motorized burnisher. They are both cheap 6" grinders with 1/2 arbors. I also bought a pro edge burnisher that is supposed to fit motors with a 1/2" arbor, but the hole doesn't extend deep enough into the dowel. See picture for why it's not fitting. The screw is tightening on the thread and thus the burnisher is not sitting perfectly straight on the arbor. Turn it on and it's not pretty. 

This is my first experience with modifying power tools and three trips to the hardware store later, I can now see why people shell out big $$ for the ready-to-go edge finishers. 

I've seen plenty of threads about this working but apparently I'm missing something. Can anyone tell me exactly what brand/motor they bought to make this work? Any help is appreciated.

[bikermutt07]

I have that set up and the pro edge went deep enough to set on the shaft. Worse case scenario, take something and cut the threaded area off the shaft. You'll still save 500 bucks.

[OLDNSLOW]

You can do what mutt said above, or you can get a much cheaper bench polisher from harbor freight and mount the burnishing tool on it.  the polisher from HF is probably 70 and it you get a 20% discount coupon than it is even less.  There have been discussions here on the board as to whether a motor should run at 1750 or a little over 3000 rpm, if you use a 3000 rpm motor you would want to use a little less pressure when burnishing.  There will no doubt be others that will chime in as to what rpm to use so on and so forth, but depending on the route you take will still result in a learning cure as to what best works for you.  Keep in mind that what works well for one person might not work for another and only time and practice will get you to the place where you want to be.  Oh and I almost forgot to mention that you can look at amazon as well for (2) speed polishing motors that will have different size shafts.

Good luck 

[JLSleather]

You (anyone) cannot say "a burnisher should run at x-rpms" without knowing the diameter of the burnishing tool.  I have two burnishers - one is about 3/4" diameter, and one is a 2" diameter.  If you run them both at the same rpm, the 2" will be running almost 3 times faster on the leather (surface feet per minute).  To get the same effect with the 2" as you get with teh 3/4', the speed would need to be reduced.  To have the effect the same, the 2" would need to run 3/8 as fast (rpms) as the 3/4".  To run the 2", you would need to "turn it down" to less than half the same speed.

That said, I run my 3/4" in a drill press - and it's jsut a guess, but I'd say it's running about 500 rpm.  The 2" I turn down as low as it will go (variable speed) and still don't like it, but can't turn it down MORE.  If I didn't have the smaller one, I'd make something to adapt it to the drill press!

But for those who like quick 'n' simple... while aguycould cut off the threaded end of the arbor, it's much simpler to simply drill a clearance hole in the burnisher to clear the threads.  Looks like a guy only need about 5/8-3/4" ...

Oh, just FYI.. this is the basis for, and the reason, why speed reducers work on machines.

 

Edited September 29, 2016 by JLSleather

[megganpowell]

Thank you everyone for your input. Turns out it was the arbor itself catching on the burnisher, not allowing it to go all the way on. I ended up grinding the shaft down in the middle where it was uneven (thanks, China) and problem solved. Still doesn't explain why the Ryobi didn't work either.

This bench grinder is not a variable speed and I don't necessarily want to wear down my already well-loved drill press so I guess it's 3200 rpm for me until I feel like messing with power tools again. I'd rather be craftin'.

[bikermutt07]

Ryobi (and harbor freight) isn't really known for precision or tight tolerances.

[ricroy]

I made an electric burnisher from an old Emerson model # 7 1/3 hp. @ 1725 rpm... i was able to finally find a saddle pad of 100% wool felt online... i made 1 3/4" donuts and compressed them on the mandrel i bought at a hardware store... i glued some veg tan together to make a groove in the donuts...i made 2 groove widths...you don't want a motor that turns too fast... in John Bianchi's 3 volume set on making a holster and belt, he uses a 1750 rpm motor... a really good video set to have to learn with...