Thread: Lapping Stones Compared

Waterstones need lapping on a regular basis. I've heard some concerns expressed about some lapping stones not being as flat as you would expect. Is the more expensive DMT course or extra-course a clearly better choice? If this has already been addressed, I'd be grateful for a link.

I've got the Naniwa flattening stone, and have yet to use it, my Nani 12k seems fairly flat, and I've read here that if the blade sits evenly on the stone, you're good to go...think I read that comment by Lynn...

I've got the Norton flattening stone. I've had good results with it, but my concern is leaving coarse grit from it whatever stone I'm using (like Norton 1K) to flatten my Norton 8k and Naniwa 12k. Anybody have a good method for flattening a high grit stone and also polishing / smoothing it down / removing coarse grit?

When I first started -- back in Ought-Six -- I bought a Norton flattening stone (220-grit), to go with the matching 1K and 4K/8K combo stone. Time passed, and I read that the Norton flattening stone often need to be flattened, itself. More reading on the subject led me to purchase a DMT-8C (325-grit) from Dia-Sharp, and it became (and remains) my sole lapping stone.

I had occasion to borrow a DMT-8XC (120-grit) from JimmyHAD, in order to flatten my (b|s)adly unflat Spyderco-UF finishing stone, but I've got no need for one of my own.

Smooth shaving!

Money spent on the Norton flattening stone is wasted for our uses. Maybe the axe and chisel folk can find a use for it, but otherwise it's a doorstop.

The coarse DMT (325 grit) is the way to go for normal lapping purposes. The extra-coarse can be useful for dealing with seriously out-of-true stones, but if you only buy one lapping tool the coarse will serve you well. If the cost of the 8 inch plate is a problem, the cheaper 6 incher will also do, though it requires a little more finesse to ensure that you don't dish the stone.

Before touching a stone, DMT plates should be prepared with some figure-eights on a rough surface, such as a sidewalk or out-of-the-way garage floor. This will knock off any outsized diamonds that would otherwise gouge furrows in your hone. Only takes a second.

Originally Posted by Ecl

Money spent on the Norton flattening stone is wasted for our uses. Maybe the axe and chisel folk can find a use for it, but otherwise it's a doorstop.

The coarse DMT (325 grit) is the way to go for normal lapping purposes. The extra-coarse can be useful for dealing with seriously out-of-true stones, but if you only buy one lapping tool the coarse will serve you well. If the cost of the 8 inch plate is a problem, the cheaper 6 incher will also do, though it requires a little more finesse to ensure that you don't dish the stone.

Before touching a stone, DMT plates should be prepared with some figure-eights on a rough surface, such as a sidewalk or out-of-the-way garage floor. This will knock off any outsized diamonds that would otherwise gouge furrows in your hone. Only takes a second.

What about the Naniwa Flattening Stone?

Originally Posted by JBHoren

When I first started -- back in Ought-Six -- I bought a Norton flattening stone (220-grit), to go with the matching 1K and 4K/8K combo stone. Time passed, and I read that the Norton flattening stone often need to be flattened, itself. More reading on the subject led me to purchase a DMT-8C (325-grit) from Dia-Sharp, and it became (and remains) my sole lapping stone...
Smooth shaving!

My path exactly, but that I checked the NFS and it was true-just wouldn't cut the other Nortos for diddly squat. Ever.

Originally Posted by Ecl

Money spent on the Norton flattening stone is wasted for our uses. Maybe the axe and chisel folk can find a use for it, but otherwise it's a doorstop.

The coarse DMT (325 grit) is the way to go for normal lapping purposes...

Before touching a stone, DMT plates should be prepared with some figure-eights on a rough surface, such as a sidewalk or out-of-the-way garage floor...

Yes and Yes and you could substitute a good hard Novaculite for the sidewalk. (some of use don't have sidewalks or garages)

The rest of my input on the subject: Get a DMT coarse continuous-grit 8x3, and then if you decide you need/want/desire/ something more or less expensive you'll be well-covered until you make the decision and get the other thing. I found the DMT to be 10 to 20x faster than the NFS, Which is a LFT when you're lapping in new stones. I started with a dual-grit 6" DMT (so it'd fit my knife jiggery). When I bought the 8x3, I was quite surprised at the difference in mass. I haven't checked but the big one is easily 3 or 4x heavier than the smaller one. I also use the DMT plate as a backer for sandpaper.

(late entry)

Originally Posted by Phrank

What about the Naniwa Flattening Stone?

Never shared the room with one. Send me yours and i'll evaluate it for the crew.

I've thought about getting the DMT plate, but I don't want to spend more money right now. I've thought about using aluminum oxide sand paper on glass to flatten my stones, like I do for my woodworking tools. It gets things perfectly flat, but again I'm worried about grit getting stuck in the Norton / Naniwa. Anybody try this method for flattening their high grit stones?

Because I am a rock hound I do use my DMT plates a lot. If you buy the coarse ones you also need the smooth ones. If you don't smooth after the coarse plates it leaves a really rough hone. I doubt that anyone that is not a rockhound or is restoring very worn hones need the coarse ones. 325 is probably all you need, for that matter most could get by with wet dry and a small rubbing stone to clean their hones. As with most thing though, feel free to collect them all, they are great to have should you need them.

A simple reminder...

The commonly used DMT D8C (325) is not, and never was, designed or intended to be a used as a hone lapping plate. The D8C is usable for lapping waterstones, but you do so at your own peril. The more coarse D8X and D8XX were not intended for hone lapping either, but are more suitable for the task.

DMT states "Some DMT Diamond Sharpeners could be used (and have been used) for flattening, however, they were designed for sharpening, not flattening, therefore, DMT assumes no liability for sharpening stones worn out due to this method of use."

ONLY the DMT Dia-Flat is designed for lapping hones.