Grindstone gloat and questions

[Federico Mena Quintero]

This long weekend my family and I went to Puebla, a lovely colonial town between Mexico City and Xalapa. On weekends there is an antiques market in a few of the pedestrian streets. There is a lot of overpriced iron and sellers who don't know what they are selling, but I just couldn't part without this:

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1240 pesos, which as of today is around 97 USD. The wheel's diameter is about 43 cm. The only major flaw that I can see is that single chip on the edge, but it doesn't intrude much into the cutting surface.

The wheel is loose in its axis; the wedges are cracked; all the iron is rusty. The axis is broken on on the threaded end (third photo), but there seems to be enough meat there to allow welding a lever for a handle.

I'm thinking of disassembling everything, giving it some de-rustification, making new wedges... Now for my newbie questions :)

How does one center this beast on the axis? Just careful measuring and wedging?

How does one go about truing the surface? I can't find one of those toothed wheel dressers here.

The water tank seems a bit flimsy; maybe it's just the grime. If it's still water-tight, would you leave it as is, or would you build a slimmer frame, maybe just with a water dish under the stone? (Or is this bulky tank just to avoid water splashing everywhere?) The lower supports have tenons on them; I don't know if they were actually set into some sort of base or if they were just built out of leftover pieces.

I wetted the edge and turned it by hand against a dull knife - man, this thing cuts *fast*! :D

[Jim Koepke]

My guess is the part that is broken was holding a small crank to link it to a foot pedal.

You might have to check with a local metal worker to find what is used to dress their grinding wheels. Maybe a diamond pointer or such.

If it works as it is I would do as little disassembly as possible to put it back in to working order.

jtk

[Lonnie Gallaher]

Frederico,

Take a look at this. http://www.gutenberg.org/files/20846/20846-h/20846-h.htm#page51 Scroll down to about the middle of the file, there you will see some information on using and maintaining your water grinder.

[Federico Mena Quintero]

Take a look at this. http://www.gutenberg.org/files/20846/20846-h/20846-h.htm#page51 Scroll down to about the middle of the file, there you will see some information on using and maintaining your water grinder.

Thank you, Lonnie! Although I'm not quite getting it - it says, "It can be made true by using a piece of 1" gas pipe as a truing tool held against the stone when run dry." Say, grab a length of galvanized pipe (I think that's what I can get), and hold it perpendicular to the wheel?

Sounds easy enough. I'll try.

[Jim Koepke]

it says, "It can be made true by using a piece of 1" gas pipe as a truing tool held against the stone when run dry." Say, grab a length of galvanized pipe (I think that's what I can get), and hold it perpendicular to the wheel?


My recollection is that "gas pipe" is non-galvanized or black pipe. The zinc in galvanized may load up the wheel.

Also I think from reading this I recall that the box base is not to hold the water as much as it is to catch the water that comes off the stone. I have seen some with a bottle suspended above them to drip water on the stone as it is used.

jtk

[Federico Mena Quintero]

Also I think from reading this I recall that the box base is not to hold the water as much as it is to catch the water that comes off the stone. I have seen some with a bottle suspended above them to drip water on the stone as it is used.

Thanks, Jim, this makes sense. I was thinking of filling the tank only so the stone barely dips in the water. Once I have time to examine everything more closely and clean it, I'll see if it was actually used with water inside, or if it was dripped from elsewhere.

[Federico Mena Quintero]

Aha, I knew Stephen Shepherd would have something to say about this:
http://www.fullchisel.com/blog/?p=94

"Stones can glaze and need to be dressed, the easiest way to dress a limestone grind stone is to saturate it with water then use a piece of hard steel as a scraper and smooth off the surface. A flat piece of sandstone or other abrasive stone can also be used to dress an old stone."

[Zach Dillinger]

I'd say that there should be a crank on that arm, but not necesarilly a foot treadle. You see a lot more crank arms than treadles, at least in my part of the world. Nothing stopping you from rigging up a foot treadle, should the idea grab you.

[george wilson]

We had those old style stones all over Williamsburg. They usually had SQUARE holes through the center. As toolmaker,we were asked to make axles that had 8 bolts. They were in groups of 4 on each side of the stone,and the bolts and axles could be fed through the square holes in the wheel. Then,the 4 bolts on each side were unscrewed until they touched the insides of the square hole. They were adjusted until the stone would run true.

I hope thin makes sense. It was an easier system than trying to put in wooden wedges,by a long shot. Even if the hole is round,if you use short bolts,you can put the axle and bolts through the hole.

Do NOT leave the wheel sitting in water. It will soften the side that got wet,and the wheel will wear unevenly. We put a drain plug on all our troughs. We made those troughs ourselves.

That axle looks pretty bad,and so do the bearings. Make sure the bearings are o.k. before you go welding a handle on them,or you won't be able to get the axle out of a bad bearing. We did not use elaborate bearings. We drilled a hole through each side of the trough,and just put in a short piece of copper pipe for a bearing. They never wore out because the speed was so slow.

You should think about removing that old axle and making a n axle with the bolts in it for adjusting the wheel. The center portion of the axle does not have to be square. Round will work fine. Just drill and thread the holes to screw in the bolts,which should have hexagonal or square heads. Hexagonal would be easier to reach into the hole and adjust with a wrench.

Sometimes the old timers would insert the axle and pour the hole full of lead,but that would be tricky unless you somehow knew exactly when the axle was square to the wheel.

[Zach Dillinger]

You could also use a very hard wood for bearings since, like George said, the speed is so slow and there is very little wear.

[george wilson]

Some of our oak troughs did not have bearings. They were just drilled holes. Over the nearly 4 decades I was there,I never noticed one wearing out,though it wasn't a conscious concern of mine at the time.

[Federico Mena Quintero]

We had those old style stones all over Williamsburg. They usually had SQUARE holes through the center. As toolmaker,we were asked to make axles that had 8 bolts. They were in groups of 4 on each side of the stone,and the bolts and axles could be fed through the square holes in the wheel. Then,the 4 bolts on each side were unscrewed until they touched the insides of the square hole. They were adjusted until the stone would run true.

George, you are full of pure gold. This makes perfect sense, and seems like it would be the easiest way to center the wheel. I'm thinking of having the axis-with-bolts, and a strip of wood on each side to pad between the bolt and the stone (the stone's hole seems to be square).



That axle looks pretty bad,and so do the bearings. Make sure the bearings are o.k. before you go welding a handle on them,or you won't be able to get the axle out of a bad bearing.

Well, the wheel runs smoothly. It feels a bit wobbly, but I think that's because it's not centered and not 100% tight to the axis. Maybe the axle still has some life to it. Once I take it apart to do the above, I'll be able to tell better.

Thanks for your great suggestion :)

[Zach Dillinger]

I'd be really, really careful about using wood in any way in that axle hole. After all, you're going to be using water and if you've got the wood tight against the stone, and the immoveable axle, you might split the stone if / when you get the wood wet.