Oops, I flattened my new Norton Flattening Stone

[anthony wall]

you need to keep turning the top stone i should have said

[george wilson]

You usually see the old 2' diameter sandstone wheels at antique places. However,I'll bet you could buy flat sandstone pieces,possibly rejects,from a place that sells stones. That's probably a good way to get a cheap,or FREE flattening stone.

One time in Williamsburg,I was at the Gunsmith's Shop. A young guy was trying to flatten a black Arkansas stone with a piece of 600 wet or dry wrapped around a file!!!! I told him to get out the sandstone wheel from its trough. We laid it flat,poured on some water,and in a few minutes had the Arkansas stone flattened. I picked up that trick from the old English furniture conservator in 1970. It does work great,though probably NOT ON CERAMIC stones. Best use a diamond stone on those. I flattened my Spyderco white stone on a diamond stone under a faucet.

Ceramic stones are many times harder than Arkansas.

[David Weaver]

A young guy was trying to flatten a black Arkansas stone with a piece of 600 wet or dry wrapped around a file!!!!

Holy cow. I would change that guy from hourly rate to piece rate if I saw him doing that.

[john brenton]

God, David, that was a brutal description. It sent a chill up my spine. Yeck...I know that ceramic on ceramic sound...if you can even call it a sound. It's more like vibrations of horror.

like sticking your head out of the car window and pressing your teeth against a galvanized guardrail as the car goes down the road. Ceramic on ceramic is not a good idea.

[Mike Henderson]

you need to keep turning the top stone i should have said

Doesn't matter what you do, you can't guarantee that you can get two flat stones by rubbing two stones together. You'll get two conforming stones, and usually, one is convex and the other concave.

Mike

[Michael MacDonald]

I have a norton lapping stone too... found out the hard way that it doesn't stay flat for very long. I was using it regulalry to "flatten" my water stones... and my waterstones ended up with a very noticable hump (rather than the normal depression) down the middle from end to end... despite this, it took me a while to notice. and the lapping stone was totally concave... it was hilariously sad.

so here is what I am doing. I still like the lapping stone--I can use it for a quick touch-up over the sink between each chisel. However, before each sharpening, I stick some sandpaper onto glass and run the lapping stone against this.. the glass isn't thick enough to be rigid, so I make sure to lay it flat on a presumably flat counter surface. I mark the lapping stone just like a waterstone with a pencil and look for the marks to wear off...

this is working better, though I still have some issues. I find when I flatten the backs of the chisels, the water stones always seem to work great on a portion of the chisel back about a 1/4 inch away from the edge... I have to release the pressure on the shank and double the pressure on the edge to get the stone to "hone in" on the last 1/4 inch. still learning by trial and error and $$.

[John Coloccia]

Doesn't matter what you do, you can't guarantee that you can get two flat stones by rubbing two stones together. You'll get two conforming stones, and usually, one is convex and the other concave.

Mike

Exactly. 3 is key because there's no way to get three surfaces to all match up with each other unless they're all flat.

[anthony wall]

42 years a cabinet maker ,always used this method and never had poor results with it ,my mentor taught me this way and he was a cabinet maker for 40 plus years ,he was probably taught the same way by his teacher so i guess it would be pretty difficult to end up with out of flat stones

[Mike Henderson]

42 years a cabinet maker ,always used this method and never had poor results with it ,my mentor taught me this way and he was a cabinet maker for 40 plus years ,he was probably taught the same way by his teacher so i guess it would be pretty difficult to end up with out of flat stones

It's actually pretty difficult to wind up with flat stones if you only use two stones. My guess is that you were able to use the stones the way they came out, even though they weren't flat, and never checked them for flatness.

Mike

[anthony wall]

you cannot effectively sharpen a jointing plane blade without a perfectly flat stone and my jointer blades were always square and level across the blade just as they needed to be. cant understand why you are knocking this method when it obviously works fine. try asking other apprenticeship trained cabinet makers if it worked ,i also would be interested to hear if they were trained differently as all the ones i know used this method.

[Harlan Barnhart]

I have a norton flattening stone and don't have any problems with it. I am careful to rotate as I use it.

[David Weaver]

As i said above, i really didn't have any problems with mine once i flattened it, either, it worked quite well. If i had kings, I'd still use it because the mud they make is a nuisance on a DMT unless you go really coarse and waste off a lot of stone, and then the DMT coarse wastes a lot more finish stone than is needed.

[Mike Henderson]

you cannot effectively sharpen a jointing plane blade without a perfectly flat stone and my jointer blades were always square and level across the blade just as they needed to be. cant understand why you are knocking this method when it obviously works fine. try asking other apprenticeship trained cabinet makers if it worked ,i also would be interested to hear if they were trained differently as all the ones i know used this method.

Don't take my word for it. Do a search on the Internet and you'll find that it requires three (or more) surfaces to guarantee that you have a flat surface. With two surfaces you'll get two conforming surfaces. Two flat surfaces are conforming but there's no guarantee that you'll come out with two flat surfaces, and the probability is that you won't.

As an example of this, when you grind a small telescope mirror you start with a glass blank (which will become the mirror) and a glass tool. Both start off fairly flat. You rub the two pieces together with the blank on top, rotating the blank and the tool occasionally, with a grinding paste between them. Very soon the blank becomes concave while the tool becomes convex.

But as I said above, don't take my word for it. Do a bit of research on your own. Old (but erroneous) beliefs die hard.

Mike

[David Weaver]

I think there is a condition of two stones that's missing here. One of them is not going to be convex while the other is concave. They are both likely going to similar in how they are out of flat. If they are close to the same hardness, I don't see how they could end up being very far from flat when you're done. they may not be as flat as three stones, but certainly it doesn't seem unlikely that they could be easily flat enough to do good work with them.

I have never rubbed stones together, but I get the sense that with as many people who have actually made things who have used the two stone method, that it might not be as simple as "a book says you can't" or "the interent says you can't". It seems likely that it is more "under some conditions, you can't".

[Mike Henderson]

I think there is a condition of two stones that's missing here. One of them is not going to be convex while the other is concave. They are both likely going to similar in how they are out of flat. If they are close to the same hardness, I don't see how they could end up being very far from flat when you're done. they may not be as flat as three stones, but certainly it doesn't seem unlikely that they could be easily flat enough to do good work with them.

I have never rubbed stones together, but I get the sense that with as many people who have actually made things who have used the two stone method, that it might not be as simple as "a book says you can't" or "the interent says you can't". It seems likely that it is more "under some conditions, you can't".

I can relate a problem I had with the Norton flattening stone. I bought one because I thought it would be an easy way to flatten my water stones. Then I started having problems with things I was sharpening and discovered that my water stones were not flat but were concave. The reason they were concave was that the Norton flattening stone had become convex. Essentially the same as the telescope mirror situation I mentioned above.

So the problem does not just exist in books - it exists in real life and I experienced it personally.

Mike

P.S. I now use a DMT diamond plate for flattening my water stones and have not had any more problems.