Breaking in a DMT diamond lap

[Leigh Betsch]

I picked up a DMT Duo Diamond lapping stone from Rockler a couple of days ago. The product literature says that it takes a while for the diamond surface to break in, and you will get a better finish after it breaks in. My problem is that I get a much better finish with the "red" (25 micron 600 mesh) than the "green" (9 micron 1200 mesh) side. I've flattened the back on one 1 1/2" chisel, and one 2" plane iron, so I would think the diamond is broke in by now. The green side feels smoother to the touch, and it feels smother when cutting but the more course red side still gives a much better finish. Anyone else have this issue? I need a better finish than what I'm getting off the course side but the extra fine side is worse. I'm thinking about returning it and getting a different diamond stone. I'm pretty well sold on the diamond stones, faster and flatter than my water stones but I've got to get a better finish. Assuming I can get a replacement diamond stone that will produce a 9 micron finish does anyone have a recommendation for a finer diamond stone, or maybe a finer ceramic stone?

[george wilson]

I have used the white and black Spyderco ceramic stones for many years. I flattened the white stone with a diamond stone. When the white stone gets little flecks of steel in it,which it will,I scrub it with the diamond stone again.

Some think the white stones are too hard to flatten. Been a lot of discussion. When you get the white stone flattened,it will never wear out. I scrubbed mine under a water faucet for maybe an hour when I got it,but mostly to get rid of some ceramic fuzz on it from being manufactured.

The fastest way I've found to get a sharp edge is to use the diamond,then black, then white ceramic. After that,just a bit of stropping on leather with some Simichrome spread lightly on it. Let the Simichrome really wear out. Don't use it often.

[Jon Toebbe]

The fastest way I've found to get a sharp edge is to use the diamond,then black, then white ceramic. After that,just a bit of stropping on leather with some Simichrome spread lightly on it. Let the Simichrome really wear out. Don't use it often.
I've recently started using the Spyderco bench stones after reading George's glowing reviews. I use sandpaper on a flat marble tile ($3.99 at the BORG) for rough work, and ceramic stones for honing. It's quick, non-messy, and I've been very pleased.

Of course, I live near Golden, CO -- so I handpicked my white stone for flatness after the first one I bought turned out to be too warped from the kiln. The extra-fine white stone is exactly the same ceramic as their regular fine white stone, but it's been machined flat after firing. I have this (literally) straight from the horse's mouth. My local WoodCraft had the extra-fine for no more than the medium or fine... well worth it to save the extra step of flattening.

I'm told the medium will (slowly) wear, but the white stones are pretty much forever, if you take care of them.

[Leigh Betsch]

Thanks for the info. I'll get a pair of Spyderco ceramic stones on order as soon as I can divert SWMBO's attention away from the check book. Then my water stones are going up for sale.

[george wilson]

I am glad to hear that the extra fine white stone has been flattened. I had to flatten mine,and so did my journeyman. But,we didn't find it that difficult. Probably luck is involved. I suggest spending the extra on the super fine if it's already flat. Most of the previous discussions have revolved around the stones not being flat.

I've never seen a "black" (more like brown) Spyderco that wasn't flat. In all,I have bought 3 pairs of stones for different shops. The black ones may be machined flat too?

[Jon Toebbe]

I've never seen a "black" (more like brown) Spyderco that wasn't flat. In all,I have bought 3 pairs of stones for different shops. The black ones may be machined flat too?
Nope, the medium and fine stones are sold "as fired" from the kiln. Only the extra-fine gets machined. I don't pretend to know much of anything about the chemistry of kiln-fired ceramics, but maybe the larger particles in the medium stone conspire to keep more resistant to warping?

Heck, I go to School of Mines... I'll check around with some of my friends in the Materials Engineering department. Spyderco gets their stones fired in Golden, so somebody in the Materials department is probably a consultant of theirs.

For the record, my brown/black/medium stone was dead flat out of the box, too. I sorted through probably half a dozen fine white stones until I found one that was flat. I never took a close look at the extra-fines, but that was my backup plan in case I couldn't find a flat fine stone. The folks at the outlet store were very indulgent of me rooting through their stocks, and made it very clear that I wasn't leaving until I was satisfied. "Well, if you insist..." :)