How do you flatten a Norton flattening plate?

I have a Norton lapping plate that I just discovered is not flat, but is instead, convex. Is there a way to flatten it? If so, with what?

Thanks!

I think they are 220 grit ? Not sure. Sandpaper of a coarser grit on a flat surface. Best bet is to forget it and go for a DMT D8C continuous plate IMHO. :shrug:

If I'm not mistaken, I think you can lap it with the DMT8C. Even if the Norton is lower grit, it's much much softer than the DMT. Unless anyone has tried and knows it doesn't work...

DMT 325 plate is the way to go.

Thanks for the repies and info. The DMT 325 must be the greatest thing since sliced bread. Right before posting this thread, I had just finished ordering one from SRD. It should be here by Thursday

Thanks!

150 grit silicon carbide powder on a glass plate will flatten AND deglaze your Norton. The DMT will flatten, but not deglaze.

I love DMTs, but I think SiC is better for this particular job.

kcarlisle,

Before I got my DMT325, I used to flatten the Norton Flattening Stone with 160, then 220 silicon carbide paper on glass (using lots of water with detergent in it).

Have fun !

Best regards

Russ

I agree with using loose SiC grit. No sense wearing out an expensive DMT. I like using a piece of flat steel (called a kanaban in Japan) instead of glass; it seems to help hold the grit in place, but glass works fine too if that's what you have. The back side of a DMT is perfect for this. You pour a teaspoon or so of grit onto the flat surface, add a few drops of water and rub the stone in circles or figure-eights. I've flattened silicon carbide oil stones, which are some of the most difficult stones to flatten, using this method.

I've used 90x from lee valley. 36x from the tools from japan store works much faster though. Japan wood worker also sells a 60x. All of it is inexpensive.

It's funny you brought this up. I tried using my norton flattening stone to flatten the previously mentioned SiC oil stone. It was really stupid idea. I ended up shaping the flattening stone to the the shape of the bowed oilstone.