Norton or DMT Diamond Stone for Flattening Chisels & Water Stones

[rick bear]

This week I took a private lesson with John McCormack, woodworker extraordinaire in San Francisco. We went over sharpening, flattening a chisel, and finally making a compound mortise using hand tools - more on that in another post...

We spent a fair amount of time working one of my Marple chisels - see photo below. It is not done yet, you can see from the grind lines. We used a DMT 8" coarse diamond stone, equivalent to about a 240 grit. This about a $44 stone on Amazon. Optionally, I'm looking at a Norton 11" stone, 220 grit, which cost substantially more, $130, plus shipping.

I expect to use the stone for flattening my chisels, and water stones. The stone in the photo below, is a new Bester/Imanishi 10,000 from Lee Valley, measuring 8" in length. I would think the longer Norton stone would do a better job on flattening the Imanishi stone.

Suggestions, recommendations? I've used 240 grit sand paper on the wet stone, seems to work well, but would not want to use it on chisels - would take forever.


One other question, even with using lots of water and careful cleaning, I notice my new Imanishi stone is developing black "flecks." You can see them in the photo below. Is this typical? Will it hurt the performance of the stone? This is all new to me.

Thanks - Rick

http://www.vuidesign.com/Machines/water_stone_marple_chisel.jpg

[David Weaver]

8" is long enough to flatten any bench stone, including the 12+ inch norton oilstones.

I don't know anything about norton's diamond stones, but I believe someone else makes a diamond stone that is narrow and long, too.

If you want to use the thing to flatten chisels, buy a second one when it dulls and then use the second one only for flattening waterstones. They seem to lose at least half of their effectiveness in flattening stones once they have some wear on them from sharpening tools.

In case it's not clear, save your money and stick with the 8" DMT (or 2 DMTs if you want to use one for initial lapping, still cheaper than one norton).

I know it seems an extravagance to have more than one diamond hone. I don't use them for sharpening much, but I somehow have ended up with 6 of them (two of them are for stones only - one for waterstones and one for oilstones). I could get by with 2 just fine, though - i learned some lessons on the first two (which I wore out).

[john brenton]

I would still opt for the long diamond hone. It's nice to have that extra length for longer strokes.

I am seeing that I would have done just as well sticking with sandpaper on the lower grits. It's not a waste because the diamond stones are good for flattening the stones, and a quick refreshing of a worn edge or bellied bevel...but I wouldn't use a diamond stone to do any heavy removal. The sandpaper or a careful grinding is better.

[george wilson]

If you have a stone dealer near you,a flat piece of sandstone(which can go by other names,like Bath Stone(in Bath,England),can do a quick job of flattening even black Arkansas stones,when used with water. Just a piece of discarded,broken sandstone will do just fine. We used to lay our sandstone wheels flat and pour water on them,to quickly flatten stones in Williamsburg. I learned the trick from old Mr. Simms,and taught the other craftsmen to do it.

[Jon van der Linden]

If you're going to flatten with another waterstone, I'd use the next lowest grit, not the lowest grit available. So 5k or so for the 10k stone. Personally I've been using a diamond plate, but somewhat finer than the coarse. The coarseness of the flattening stone can effect the results off the fine stone. I know Tormek supplies a grading stone for their wheels to give either a coarser or finer result with the same wheel. I've also noticed this effect while using my Nortons.