Disc Grinder question...

Kalindras

Kalindras

Joined
Aug 24, 1999
Messages
933
Howdy, all!!

Just got a Grizzly 12" disc grinder as an early Yule gift from the fam'bly, and fired it up this weekend. And, of course, now I have questions... :rolleyes:

First and foremost...having already managed to jam a blade down between the table and the disc, and thus reinvent the wheel (okay, discover that it's "safer" to use the UP-rotation side for grinding (wear your glasses, or the faceful of grit will KILL you!!)), I was wondering--how far from the wheel do you folks adjust your table for? I see pictures in my various books of makers using the down-rotation side (so that the rotation of the disc carries the blade into the table), but when I tried that, it was almost impossible to keep the blade from getting sucked down and trapped between the disc and the table.

Do you just cram it against the disc, and let the disc grind its own micro-clearance? Is my technique just wrong? Or is there some other, unknown factor that I'm missing?

Also, which side really IS the safest to grind on? I mean, having already had my fingers gunched when a blade got stuck, and eaten a faceful of steel grit, I can't really tell where I should be grinding from...?

Any tips from you old pros would be much appreciated...heck, any tips from the utter newbies would be appreciated, too! Basically, anyone who knows more about this than me (which qualifies everyone!!)... :p

Thanks in advance, folks!
 
I think most folks just remove the table because of what happened to you. It's too hard to avoid. Just hold the blade against the disc on the down turning side.
 
Kal, You might think about putting a piece of phenolic on top of the steady rest, as close as possible to the disc. Also, install a foot switch, for safety and will help control the RPM. I beleive the best way to grind steel, with a disc, is to have the disc in the horizontal position.
Ken (wwjd)
 
(Newbie here)
I have seen pictures of discs actually hanging over the edge of benches. Maybe so that the only thing to stop the blade is the floor and hopefully not your foot or leg.
(It didnt look like a good idea to me, but to each his own.)

I think the horizontal makes the best sense.
 
Kal, if you are doing profiling, the workrest is great. But for bevels they can be dangerous, as you found out. I only use mine for flattening, but I also do it on the down side. My discs are mounted in the conventional way, vertical. If something gets away, I want it to go downward, rather than across the room, in God knows what direction. :eek: . You might also want to check on a beveled face 9" disc, from Rob Frink. You can use 9X11" sheets, and not worry about hitting the upside, when doing long blades. ;)
 
Mike,

Cool pic. What sort of motors do you have attached to your discs? Do they run in opposite directions?

I have the 9" from Tru-Grit. Not cheap, but a precision piece of equipment. I saved about $400 by finding my own variable speed reversible motor on Ebay. It just happened to be the exact one Tru-Grit sells with theirs, so I just ordered the disc, mounting base, and work rest.

I like the work rest for a few things: profiling (as already mentioned), dovetailing, flattening the part of handle scales that will meet the guard, etc. My disc is held onto the motor arbor with two allen/hex screws. I just adjust the disc so it is about 1mm from the work rest and have never had a problem with anything getting between the disc and the rest.

John
 
John, the gray one is a Baldor, the one by the fan is a GE. They came off a couple of grinders that got VS motors.
Both run CCW.
 
Many industrial motors can use these reversing switches.

rev-switch.jpg


This way you can run the disk in the appropriate direction depending on which side you are working. These switches are can be used on single phase AC motors. They are available from typical "power transmission industrial suppliers" and from my web site with motors.

-Rob
 
I have a drum switch just like Rob has pictured,it works slick
I had to figure out how to wire it but I got it:)Mike I like the pictures of your shop,I would love to see some more of your work:D
 
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