Dressing old pedal operated grind stone?

J

jviss

Joined
Oct 3, 2011
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I recently acquired an old, pedal operated grinder. The stone is 21 1/2" in diameter, 2 5/16" wide. The surface of the stone is in terrible shape: clogged with some kind of material that shouldn't have been ground in this; low spots, etc. It needs to be trued up, laterally, too.

After I correct the wobble, how should I go about dressing the surface? I'm sure I will need something that cuts the stone quite aggressively, at first, then a finer dressing.

I was thinking of using a belt sander at first, maybe fixtured so it remains square and at a fixed radius. I thought I could go through a couple of grits of paper with this. Then I'd switch to a finer dressing tool, but I don't know what.

Any and all recommendations on this will be greatly appreciated!

Thanks,

jv
 
Type in Google "grinding wheel dressers"
Some that I have used:
Grinding Wheel Dresser that has multiple stars wheels. I think you can get a cheep one at Harbor Freight
Industrial Diamond - more costly - Comes in a holder
 
Here are a couple of pictures:

The grinder:
grinder.jpg


Close-up of the stone:
grindstone.jpg


Believe me, I've googled the heck out of this topic! I know a bit about grinders and grinding - I have a basic 6" bench grinder, a pedestal carbide grinder (also referred to as a spindle shaper), and a Clausing 6" surface surface grinder. I have a star dresser (for the bench grinder) and a diamond dresser for the surface grinder. I tried the star dresser on a lark, but as I imagined, it won't doesn't a dent in it, or, I should say, doesn't make a difference at all, given that the stone is so out of whack.

I don't know anything about the stone, it's composition, etc. I am just assuming I can belt sand it into the correct profile, but again, no experience with this kind of grinder.

Thanks,

jv
 
wow. that thing is in rough shape. did someone put mortar on the side where all the grooves are? it looks like its seperate from the stone.
 
I wonder if one of those water jet cutting machines could true that up? Probably be expensive as hell though.
 
A thread in the Axe and tomahawk section had some old school directions on making new grind stones. Didn't look that difficult and would probably be a fun project.
 
Perhaps the lines are there for a purpose..? I mean, maybe they're there so that one can chip off the layers somehow. I don't know, I'm just brainstorming.
 
The square hole in the stone should be much bigger than the drive shaft. This is so you can use shims and small wedges to get the wheel as close to center and as perpendicular as possible with respect to the shaft. Assuming you can move the nut to get in there that is, there looks to be plenty of rust on the drive shaft. These stones run slow, and you are holding the knife/tool freehand, so a little out of round won't be as much of an issue in use as it is on a powered grinder.

For dressing off gunk on the edge of the stone, I'd try an abrasive grinding wheel dressing rod or a "Grading stone" like Tormek sells. The diamond dresser will work, but it's a long way round that stone one diamond width at a time...if you have a multiple diamond dresser that will be faster. These grinders usually had a can of water set up to drip on the stone hung over them somehow, and I would suggest setting something up and doing the dressing wet to keep down the dust.

I would dress just enough to remove the gunk and get a reasonably true surface. This is not the type of grinder where you grind on the corners of the stone, those chips won't bother you when you are sharpening most knives or tools. These stones wear, and you will eventually get down to the full width of the stone, if you are careful and lucky and don't put new chips in the edge that is...I think setting up a belt sander to dress this stone will be overkill, but YMMV. Just beware that these natural stones can blow up if driven at even modestly high speeds so don't let the belt sander "drive" the stone as it abrades it
 
I would suggest grinding on the surface of a cinder block, just to wear through all the clogged material. Just hold the block in place and pedal away.
 
I grew up with a worse shape, older wooden one. truing it up and dressing the wheel are two different things as Mahoney says. Get it as balanced as you can, then take the surface layer off while turning at normal speeds. We just used files/rasps to rough it up as it turned. It was only for hoes, picks, some tines and disks but not usually. Knives and axes are still ground the same way.

That's a nice find BTW. The stone looks almost new compared to most I've seen. I've never seen one as true round as modern grinder wheels BTW. Use it like it is once you get it roughed up. That doesn't look like a model grinder, or stone that was made to be upgradable with a motor. Also, keep the thing well greased. Clean as much old grease off as you can and re grease it with some new stuff. Waterproof, simple grease.

Joe
 
I think it is beyond help and you should just send it to me, I'll get rid of it for you. :)
Nice find!
 
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