Yeah I wouldn't touch the sigma 120 with anything diamond! I don't really know what I'd do the flatten such stones, good thing I don't need em'. I do want a sigma 400 or maybe the Gokomyo ryu 300 dual density stone, I have a butt load of old stanley planes and chisel sets to flatten soon.
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The Sigma 400 is a fast stone, and the 1,000 takes its scratches out as easy as any other step between stones. I wish I had bought it years ago. The only "stone" I have that's coarser is a diamond plate x-coarse, but it rarely gets used. If the 400 is not enough, it goes to the CBN wheel. The 400 really speeds things up when 1,000 is not quite enough for flattening the back of a chisel or plane iron. For flattening the finer stones I have one of the Atoma 400 replacement sheets on one half of a 9x12 granite surface plate that stays in one sink. There is another 200 sheet on its way for the other half for coarser stones. I probably would have ordered 140 if I had seen Patrick's post before I put in that order.
Last edited by Tom M King; 01-02-2016 at 1:52 PM.
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For grinding of japanese chisels I make slurry on a Norton crystolon with DMT xxcoarse plastic backed honeycomb stone that can be had for about $35. I spray with non aerosol WD40 for slurry part, but use honing oil for actual grinding. Seems to work ok, and is not too messy or expensive. Kind of like waterstone, but works on a cold porch.
Hi Tom,Originally Posted by Tom M King
What do you use to flatten the Sigma 400? I use the sigma 1.2k to flatten backs and it works well enough, but when you have a lot of work to do it takes too long.
Thanks,
Matthew
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I have some SC grit left from when I built telescope mirrors when I was a teenager (1960s). To use the grit on, I just lay a float glass window pane on top of the granite plate in the sink, on top of a piece of that rubbery drawer liner screen stuff. That's what I ordered the 200 Atoma sheet for-to avoid having to mess with the grit and window pane, but we'll see how that goes.
I wouldn't recommend using a window pane normally, but we have a bunch of float glass panes out of windows in the house we're working on now-lots of sash work, and we're replacing the float glass with cylinder glass.
Last edited by Tom M King; 01-02-2016 at 2:10 PM.
Member
It's probably worth noting that I'm conservative about such things (now :-). I don't view loose SiC as much of a hassle and I'd rather not blow through [m]any more diamond plates.
I know of people who use the #140 Atoma to flatten the Select II #240, and flattening the #400 on a #200 sheet should be less abusive than that. Just use a light touch.
Thanks. I used glass with SC power early on in my woodworking to flatten an old block plane, it cuts very fast but I didn't like it much, and felt like it cut the glass too so not as "flat" for as long. I'd be curious to hear how the 200 Atoma sheet works out for this, as I think I'll have no choice but to get one of those stones soon, that is if I value my time and energy. I also work the field, not houses but woodworking related, and will need to flatted a lot of blade backs very soon.
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Use a sacrificial plastic laminating sheet on top of the glass. It makes the lapping go a lot faster (the sheet is relatively soft and tends to "trap" the abrasive particles) and prevents the grit from scratching the glass.
Contributor
That sounds like a good idea. Plastic laminating sheet? I just toss the pane in the trash when done, but we have a big stack of them to toss right now anyway. I said Silicon Carbide, but on the outside of the cans it says Carborundum, which is the same thing.
[OP]
Member
I realize I was equating loose grit with diamond paste. Oops. Any idea if local big box stores or specialty shops would Cary loose grit?
Member
Not sure about the big boxes. Woodcraft would have it if there's one near you.
Here's the boutique version: http://www.leevalley.com/US/wood/pag...17&cat=1,43072
And here's basically the same thing (the particle size may be a bit less controlled, but definitely close enough for flattening) in bulk. There are several suppliers, I just chose Panadyne because that's what I've most recently purchased.
The difference between diamond paste and SiC is approximately the difference between $5/gram and $5/pound.
Last edited by Patrick Chase; 01-02-2016 at 5:33 PM.
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I don't know how the stuff is graded at other places, but this is pretty good in this form: http://www.willbell.com/atmsupplies/atm_supplies.htm
Member
You need to watch this video, by a guy that makes wooden hand planes.
https://www.youtube.com/watch?v=byDNeehIfmw
Member
His technique is a little sloppy (if you look at the sparks you can see that he's doing a significant fraction if not a majority of his work on the left corner of the wheel, which is bad for both the workpiece and the wheel), but otherwise a good demonstration of how to do gross material removal using a $200 CBN wheel on a $200 grinder.
Not at all relevant to the OP's request or budget, though.
Also, some of us use coarse-grit grinding stones because we like to...
Last edited by Patrick Chase; 01-02-2016 at 11:22 PM.
Contributor
I use the same CBN wheel that David does in that video, but this discussion has been more about stones for not only final honing, but for flattening the backs of chisels and plane irons. I believe Brian here has one of David's planes, but ask him if he goes farther than David on sharpening other things. David has been as big a stone Ho as any of us, but likes that way for what he does. What we all do, and want from our edges, varies. Most of my iron and chisel edges have not touched the grinder in a Long time.
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