Thread: How long will a DMT duostone last?

Groggy has expressed the view that they don't last that long.

And my experience has been similar to yours but I've done a lot of lapping with my Coarse DMT and have gone to a Shapton #120 for this purpose.

The DMT coarse is not that coarse - something like #325. And you're taking a lot off. In your shoes I'd form most of the new bevel on a bench grinder and then put the 2ndary bevel on with the bench stone.

It may be worth following DMT's advice and try cleaning the DMT with Jiff or similar (liquid kitchen abrasive cleaner). I've found that some glazing does develop over time and Jiff gets rid of some of it.

Thanks for the input Ern. Maybe I'll take a look at waterstones next, I've got a couple of blades coming in Thumbsucker's stanley order that will probably chew up what is left of the DMT.

I'm actually planning to go to Japan in June. I wonder if watersones are much cheaper bought over there?

Fuzzie - the quickest way to wear out a DMT is to use it on M2 steel (a la Thumbsucker's blades)......

That stuff makes A2 seem very easy to sharpen, and you'll be spending a lot of time on even a coarse DMT to have much effect.

In the end I did the primary bevel for my M2 paring chisels on an 8" slow speed grinder with alox wheel. I use Shaptons for the microbevel (where little material has to be removed), but when a new primary bevel is needed it'll be back to the grinder.

As an alternative, and following Ern's lead, I have a #120 grit Sigma ceramic stone (plus the gubbins required to keep it flat...) on order from Stu. I'm hoping this will be more effective on M2 steel, and also suitable for changing bevel angles on A2 blades.

I reserve my DMTs for touching up/restoring bevels and general sharpening these days, plus of course they are fantastic for keeping Shaptons flat (except the #120......). I wouldn't recommend using them for bulk material removal - at least get close to where you need to be on a grinder first !

And TS says the blades are pretty flat so maybe not much flattening of the back is called for.

Hope so. I have 3 on order.

Fuzzie, as posted elsewhere and like some other forumites, I've migrated from diamond to ceramic stones.

You could do worse than get advice from Stu of Welcome to toolsfromjapan.com

I have a high regard for his advice and blog posts.

Ern, I think they do wear quickly (I know there is an initial 'wear' period and am not talking about that). For the expense I think they are very good for soft steels and stone flattening. I would not even wave M2 at them. I am currently enjoying using a Shapton Glass stone. At 220 grit it is a good and fast cutter,

Yeah. As posted elsewhere, I've gone to a #120 Shapton Pro for blade back flattening.

Bites like a cut snake and lordy, the flattening of it will fray your nerves (also posted elsewhere).

Too many elsewheres on this forum.

Originally Posted by Mr Brush

As an alternative, and following Ern's lead, I have a #120 grit Sigma ceramic stone (plus the gubbins required to keep it flat...) on order from Stu. I'm hoping this will be more effective on M2 steel, and also suitable for changing bevel angles on A2 blades.

Yeah, well it's kind of a Sigma, 'cept it'll come in a green box.

Just for interest sake, I have a few coarse stones here and have been testing them with really tough steels. The M2 from Thumbsucker should be a dream to work with compared to the CPM 3V, M4 and 10V I have here.

The M2 blades have been heat treated to make them easier to grind, which is a great idea.

The CPM stuff I have here for testing, there's no escaping the fact they are exceptionally tough and wear resistant.

Preliminary testing has shown me that the Sigma eats the stuff, it really doesn't care which metal you feed it, it's always hungry. The Shapton M5 #120 seems to bite well, but it sheds most of it's grit before getting any work done. In fact, no real effect other than lots of expensive white slurry. The Shapton Glass Stone #120, no effect. The steel skates across the stone as though there is grease there. The Naniwa #220 actually does ok. Gets a little work done, and doesn't give up the ghost in the process.

I did actually measure how much of a 1/2" chisel was removed in 30 seconds, full bevel grind and the M5 and Naniwa combined removed 0.05mm. The Sigma removed 0.15mm. The M5 was heavily gouged, not dished. The Naniwa was shallowly gouged. The Sigma showed no effect.


I really hate harping on this, it's irritating to my nature, but I hate seeing folks spend good money on things that won't cut it. I have no such qualms on spending the money myself since I usually get stuff a heck of a lot cheaper than most of you can find anywhere, so it's less money out of my pocket and I can write the whole mess off on taxes.

Oh, Fuzzie...

When you come to Japan, generally speaking, yes, all Japanese tools and stones will be cheaper in Japan than anywhere else in the world. The best pricing comes from wholesalers which are pretty much exclusive to folks who can read and speak the lingo and actually live here. Professional tool stores are certainly less expensive, and home centres pricing is usually not bad, but the products they have in there are on occasion not that great. Common stuff like Gyokucho and Z Saws, stones and whatnot, quality is fine and price is good. Anything else, steer clear unless it looks good to you in every detail or it's just too cheap to pass up.

But don't buy everything in sight believing it's all cheap, cheap, cheap!

Interesting stuff Stu. How thick was the chisel or how long was the bevel?

Yes, I have some CPM 10V turning tools and while they sharpen on an Alox grind wheel OK, honing them with fine abrasive paste is another matter.

Chisel is 3/8" wide, 1/4" thick with a 5/8" long bevel.

Not much chisel, but still enough to give most stuff a hard time.

On the back, I think I used my #400 Atoma to get it into shape, but not all the way. It's an unfinished blade, not a complete chisel and needs to be sent back to whence it came for final finishing. I'm allowed to do anything to it except keep it.

The 3V is 1/2" wide, and looks the same as a Blue Chip in section.

The 10V I have is a very small thing, maybe 1/8" wide, and I can't really get a read on how it's working with stones because there just isn't enough metal to give the stones a hard time. Oh well, not like these will be a common tool since the maker says the 10V is too difficult to work with.

I will tell you that fine diamond paste on a suitable substrate always works. But to me, the paste makes waterstones look like the pinnacle of cleanliness. Slimy, greasy crap everywhere that doesn't wash off very easily, even though the base of the paste I am using is water based. But it does work very effectively.

Stu.

Ah, yes, I have on the 'tuit' list to finish an array of 3 MDF wheels to go on the lathe, rimmed with leather and charged with diamond paste in descending grits.

Better rug up then and pull out an old sheet to cover the lathe bed.

Thanks guys, there is some very interesting stuff in the answers!

Thankfully I'll now have some time to consider my budget and what stones to look for in Japan. Last time I was there I stumbled across Homeacc but I didn't buy anything because I hadn't planned to and I didn't know anything about the brands I was looking at.

I'll be flying in and out of Osaka this time (gotta love those cheap Jetstar fares ) , so I won't be able to land on Stu in Tokyo for a deal.

Fuzzie - I know you're going to Japan anyway, but it would honestly be much easier to buy the stones online from Stu before/after you go.

He already has access to a huge range of stuff you'll never find yourself in the stores, can recommend the best stone for the job if you ask (as several forum members will attest), and at current exchange rates his prices are great.

For example, here are some of the Sigma ceramic stones I've bought from him:

Sigma power. : Tools from Japan, Japanese woodworking tools direct from Japan.

No association with this retailer, just a very satisfied customer.

You're probably right Mr Bush, at least I have a few weeks to consider the options.

I haven't really been properly aware of the issues pertaining to the M2 blades previously and need to take that some time to more fully understand the implications of what I have bought there. I also want to keep in perspective that I'm merely a hobby woodworker.

Ahhhhh......you're in for some fun with those M2 blades !

Once you've got a good edge though, it lasts a surprisingly long time before re-sharpening is required.