Lifespan of a DMT bench stone?

emperorwang

emperorwang

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Nov 16, 2008
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I have a 200 grit DMT bench stone that I've had for about 5 years. It hasn't been my sole sharpener and have used it sporadically during that time. I'd estimate about a couple thousand passes.

Lately I've sharpened two knives on it, a Chinese steel schrade sharpfinger and a 154cm fixed blade griptilian, and it seems both knives came away with tiny notches in the edge, barely visible, but noticeably catching on my test paper. The blades are otherwise sharp. Theres no apparent anomalies in the surface of the stone.

Is this normal for an older DMT stone? Is it past its lifespan?
 
So, that's the x coarse stone. Mine has good endurance. Some of the other grits I have don't. If I did all my rebeveling with the x coarse
it would show more wear but that would be over 500 knives. Lighten up the pressure and take it to the coarse plate. Work it slow. DM
 
Might scrub the hone real thorougly with some Bar Keepers Friend powder & water, and a stiff non-metallic brush (toothbrush, etc). It may be that parts of the hone's surface are clogged with steel swarf. Softer and more ductile stainless steels can clog a diamond hone very fast when used dry or with water, with the swarf being cut away in stringy ribbons (microscopically) which blanket and tenaciously cling to the grit on the hone. The 'notches' in the edges of your two blades might be from a small bit of the hone's grit that's covered over with swarf. So, the effect will be that the grit covered by the swarf might dent or deform the edge, but not cut it.

On a very coarse diamond hone heavily covered with stainless swarf, the result would be a very heavily burred, deformed & ragged edge on the blade. You might have something like this going on, but on a smaller & more limited scale.
 
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You'd expect tiny scratches with that coarse grit; my DMT DiaSharp ultra coarse (220 grit) does the same, but they polish out on the DMT red (600 grit). I've used the same DMT bench hones for 25+ years and they work as good as new. BreakFree CLP works great to lift out the swarf.
 
Obsessed with Edges said:
Might scrub the hone real thorougly with some Bar Keepers Friend powder & water, and a stiff non-metallic brush (toothbrush, etc). It may be that parts of the hone's surface are clogged with steel swarf. Softer and more ductile stainless steels can clog a diamond hone very fast when used dry or with water, with the swarf being cut away in stringy ribbons (microscopically) which blanket and tenaciously cling to the grit on the hone. The 'notches' in the edges of your two blades might be from a small bit of the hone's grit that's covered over with swarf. So, the effect will be that the grit covered by the swarf might dent or deform the edge, but not cut it.

On a very coarse diamond hone heavily covered with stainless swarf, the result would be a very heavily burred, deformed & ragged edge on the blade. You might have something like this going on, but on a smaller & more limited scale.
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This is extremely helpful, thank you
 
I purchased the coarse and x coarse, dia sharp stones. These two plates alone were $184 to get them to my door. The coarse is getting slow in cutting after 10 years. The x coarse is still cutting better. But for the same money I could have purchased 6 Norton SiC, IM313 coarse
stones that would have given me Far better economy. So, diamond I shy away from now. DM
 
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I've owned a few of DMT's sharpening stones/tools in the past few years. I haven't owned any of their really high end equipment but I do own several of their specialty tools and have had decent luck with them overall.

The two diamond benchstones that I use to mainly reprofile a beat up blade are both relatively coarse. One of my stones is a Norton coarse diamond and it's a stone that is used in their triple flip system. But I've been using it as a benchstone and I've had great luck with it. I also own a 3M extra-coarse benchstone that I've had since about 2005. I've owned both the Norton and 3M stones for well over 10 years and neither one of them are what you would call "worn out'.

Now I am on my 3rd set of diamond stones for my Spyderco 204 Sharpmaker. But I've really used that tool much, much more than the average person would have used it. I'm not exactly sure what it is that eventually destroys diamond stones but I've heard a crosscurrent of discussion about the problem for some time now. Personally I've been far more impressed with Norton's and 3M's diamond stones than I ever have with anything that DMT ever made.
 
My 2 (extra coarse, coarse, fine, and extra fine) 4”X10” DMT stones lasted about a week. They are now as smooth as a baby’s butt. DMT says they still scratch glass, so no problem. I say they’re too sloooooow. I dumped the DMT’s in favor of Venev bonded Diamond stones.
 
David Martin said:
JD, who sells the Norton diamond stones? DM
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I would guess any vendor who would sell any of Norton's other great sharpening stones. I also own their "India" stone and a couple of others>> I got those through Garrett Wade quite some time back. I've been a fan of many of Norton's products for years. I've like Norton's and 3M's sandpaper far better than any others on the market. I think all of their's and 3M's abrasives to be quite good IMO. Over the years I've found 3M's great diamond stones to be far better than DMT. The two Norton diamond stones I have are ones you can buy for their triple flip system that is sold to commercial meat packing houses. But I'm sure you could buy them from any vendor who sells Norton abrasives.

I live here in the Kansas City, MO USA part of the country and we have probably a dozen tool vendors and contractor supply houses that carry all of Norton's abrasive products. As I'm sitting here a friend of mine just told me that the internet vendors "Sharpening Supplies" and "Chef's Knives To Go" both sell Norton's great products.

I have a question for you guys? Who might sell aftermarket stones that will fit a Spyderco 204 Sharpmaker. I would think that someone would make tri-angle stones that would fit the unit unless Spyderco patented the size of the stone but I'm not sure you can patent the size of anything? I'll have to ask a Lawyer friend of mine about that.
 
I'm not finding them on Sharpening Supplies. Norton's IM-313 does not show a diamond stone offered for the commercial meat cutters Tri-Hone. I have this system and would purchase this size diamond stone if offered through Norton. DM
 
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JD Spydo said:
(...)

I have a question for you guys? Who might sell aftermarket stones that will fit a Spyderco 204 Sharpmaker. I would think that someone would make tri-angle stones that would fit the unit unless Spyderco patented the size of the stone but I'm not sure you can patent the size of anything? I'll have to ask a Lawyer friend of mine about that.
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Sharpening Supplies carries some 1/2" triangular rods in aluminum oxide (C/M/F, or 120, 180-220, 320), which should fit the SM. They look essentially identical to Norton product, in terms of the color & grit rating, but aren't branded as such on the SS site. And they mention the rods are made for them in the USA (don't know by whom). They're 6" long, and not very expensive.

I'm pretty sure Norton themselves also make 1/2" triangular rods in their India and/or Crystolon line. You kind of have to hunt around for vendors selling them though, and the one or two vendors I've seen are kind of pricey too. As much or more expensive than even the 8" bench stones in the same lines, depending on where you buy those.

Congress Tools has frequently been mentioned here as an alternative for SM-compatible rods in some very aggressive grit ratings. They carry aluminum oxide and 'ruby' (also AlOx, but more aggressive and tougher). Don't remember if they carry these in SiC or not. Reviews sometimes indicate these work well enough, or even very good, although issues with finish of the stones are also frequently mentioned (rough edges, not straight, wobbly or too-tight fit to the SM, etc).
 
Again I've for years found that Norton the 3M's diamond stones to be far more durable than anything I've owned made by DMT. I've also heard that Atoma also has some great diamond sharpening tools as well.
 
Ok, I found the Norton diamond plates at Grainger, in 2X6" and 2X8", from 220 grit up to 600 grit. These originate from Norton's plant in Mexico. They are dia stones, made in like manner as the DMT, where the grit is attached to a nickle plate. One could then purchase the Tri-hone base and box system and install these stones. Your experience is this brand wears better. DM
 
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JD Spydo said:
I have a question for you guys? Who might sell aftermarket stones that will fit a Spyderco 204 Sharpmaker.
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The "moldmaster" line from Congress Tools has been mentioned here quite a bit, but with the caveats that OwE talked about in his post above.

That said, I don't see the point. The SharpMaker isn't really ergonomically set up for a lot of grinding. If you need to remove a lot of metal, you're better off with something else first. Bench stones, belt sander, etc.

Switching to the SM after you have an edge (or very close to it), produces great results and you don't have to fiddle around with stones that don't fit or anything else. Just use the tool as it was intended and get great results with it.

As always, just my opinion.

Brian.
 
Tiguy, when removing more metal do you use both hands and apply pressure? What angle is you jig set at? Well thought out gadget. DM
 
I use one hand only. It is tough to get good control with 2 hands on one grip/handle. A little more pressure on SiC and Al2O3, a little less on Diamonds. One side is set to 15 degrees off vertical, the other to 20 degrees off vertical (same as the SharpMaker). In use, I grind on one side of the blade and then rotate the jig 180 degrees to grind on the other.
Because the stones I use on my jig are so much coarser than the S/M stones, excess pressure is not required.
 
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