Replies

1. 
   JohnWW | Jul 20, 2007 09:40pm | #1

   The DMT stones we have in the FWW shop seem to cut as well today as when we got them five years ago.  If you are going to use a sharpening guide you will probably want to buy the larger stones.  I use their green and red stones for 90% of all the sharpening I do.

   John White, Shop Manager, Fine Woodworking Magazine

1. 
   KiddervilleAcres | Jul 21, 2007 03:41am | #2

   Hi John,

   Haven't yet done the math but I wonder how your experience with diamond stones vs sandpaper on glass compares economically?  From your response it sounds like, all things considered, the stones would make a lot of sense.

   Regards,Bob @ Kidderville Acres

    

   A Woodworkers mind should be the sharpest tool in the shop!

2. 
   9619 | Jul 23, 2007 06:39pm | #14

   John,
   YOu said that you use diamond stones for 90% of your sharpening.
   What is the other 10%? I cant tell if you mean that there are other things besides plane blades and chisels that you do with other methods, or if you mean that after using the Green and Red diamond stones, you then go to another method to do a final hone.Also, do you recommend the DMT stones with the diamond grit allover, or the ones with the "dots" of diamond grit? I have read that the dots allow the waste material to accumulate between them. If that is the case, then wouldn't the plates with the diamond grit all over them be a problem?Thanks,
   MelMeasure your output in smiles per board foot. 

1. 
   JohnWW | Jul 23, 2007 07:51pm | #16

   I use the DMT red and then green stones for my final sharpening and find that my planes and chisels are sharp enough for my needs. 

   The other 10% is grinding on a small hand cranked grinder, or a Tormek machine, to restore a hollow grind in a blade that has been sharpened to the point that the hollow is gone.  I do keep a set of small shaped Carborundrum slips in oil for sharpening curved blades but DMT makes round and half round diamond stones also.

   The DMT stones I have are all the dotted type and they work very well for woodworking tools.  I have a few small solid diamond stones that are useful for sharpening very small cutters that can get snagged on the dotted stones.

   John W.

2. 
   philip | Jul 21, 2007 06:09am | #3

   Dan, I am with John on this. I now use DMT plates almost all the time. I have had the big one for more than 10years and see no performance reduction worth noting. I use mainly unfriendly woods on which super sharp is just a waste of time: anyway the degree of sharpness obtainable with a fine diamond is good for most applications.I use kerosene, not water.
   No flatening, no extra bits of sanding paper everywhere and they are good for all steels and tungsten carbide.
   There has been mention of the diamond not performing well on steel-this is applicable to mechanised diamond wheels which tend to load and glaze if they grind steel -that is why tipped planer knives etc have two bevels, so as to avoid grinding steel when the carbide requires grinding.
   But be sure to use DMT stones- I have had a couple of other makes which did not last well.

   Philip Marcou
3. 
   spf | Jul 21, 2007 07:02am | #4

   FWIW, I have sharpened with diamond stones for at least 4 yrs, and haven't noticed a significant change in their performance.  Still FLAT, still MUCH less mess than my waterstones or sandpaper (I hate sanding anything).

   What size? I would want at least as wide as the widest blade you will sharpen. Knives being an exception...

   What grit? Depends on what you have now.  At least fine and extra fine. Coarse could be handy when removing lots of metal.

   I prefer the continuous stones over the "dotted" ones. 

   This one from DMT makes my mouth water...

   http://theconsumerlink.com/product_detail.asp?BID=DiamondMachiningTechnology&T1=TCL+D8EE&navStart=0&.

   ...soon, very soon....

    

   
   

   ---

   Edited 7/21/2007 12:51 am by spf

4. 
   hammer1 | Jul 21, 2007 07:02am | #5

   I have a pair of DMT 8" one red one blue. I've had them over ten years and can't discern any wear. They are still flat and straight. I have used them for many other things than sharpening woodworking tools. I just lapped some carburetor flanges on them today. The fine stone, I'm guessing, is equivalent to 800-1000 grit. Great for all but the finest edges. If I were to buy another, I would get one with a solid, instead of perforated, diamond surface. The perforations don't bother plane blades and chisels but fine carving tools get caught or skip along.

   You can remove a small nick, reshape a bevel, flatten backs and even lap small items on the stones. They use water so there is no oil involved. Just dry them off when you are finished. After using the fine diamond, I may use a 2000 water stone and follow that with a leather charged with metal polish. Most working edges don't have to be that sharp but there are times when you need a surgical edge.

   The diamond stones are quite fast. They are expensive but it's a one time purchase, they are unbreakable, unlike most stones. The sand paper method gets very expensive, if you are a busy shop, and you can always run out when you need it. It's easy to tear and you can't work in both directions like you can with a stone, back strokes only. I can crank all the pressure I want on the diamond and move fast. The diamond stones are also better for cutlery and can sharpen carbide. I've even flattened an old Arkansas stone on mine.

   There isn't any one sharpening method that addresses all of a shop's needs. Turning and carving tools have their own special requirements. You often do other sharpening too, axes, kitchen knives, etc. There are time when sand paper fits the bill. If you want a great and versatile stone, diamond would be my recommendation but you will want some other options too.

   Beat it to fit / Paint it to match

5. 
   troys | Jul 21, 2007 07:36am | #6

   I'll add one more vote for the diamond stones. I have been happy with mine I use them with a 8000 grit waterstone for polishing.

   Troy

1. 
   philip | Jul 21, 2007 08:55am | #7

   One thing I forgot to mention: for those of us who wish to camber plane blades (or any blade) this is easily achieved with a diamond plate-no fear of gouging or damaging a stone when you press on a corner as hard as you like....
   And taking those burrs off an edge....Philip Marcou

6. 
   PaulMassachusetts | Jul 21, 2007 03:02pm | #8

   I go to a local craft center where the large DMT stones have definitely become dull. They are used constantly and may be more than ten years old. I have the large DMT stones as a hobbyist and they are great. The large stones are the only ones to get. The stones must be patted dry after use and are left upright on edge to facilitate drying-this helps prevent rust.

1. 
   danmart | Jul 21, 2007 03:46pm | #9

   Well the inputs are really helpful. Lots of good details. I am wondering??? Purchase the DMT stones with the circles or the continuous surface?
   I think I'll get a fine/coarse stone. They sell 2 sided 8"and 10" so there is some thinking to do.Don't mean to be so hesitant but.. these are pricey.Thanks to all

1. 
   Lataxe | Jul 21, 2007 05:19pm | #10

   Dan,

   I use the 10" X 4" double sided DMT diamond stone (600 and 1200) for all straight edges.  There is no discernible wear, although after the first few times the initial "roughness" wears off.  There is no lack of sharpening ability after some years of use, including a lot of use with 10 inch HSS planer blades. 

   It can take quite a lot of metal fast so I feel no need for a coarse diamond stone - unless there is a very un-straight or deeply nicked thing to deal with.  (In which case "send it off for grinding by an expert" is my outlook).  I only ever let the planer blades get that bad, once.

   The DMTs are easy to maintain as long as you dry any water off them.  It is better to use a very thin oil, as Philip says, to avoid the risk of forgetting and letting rust get a hold of the steel substrate.  Also, I like to use it on a piece of good quality (ie flat) MDF on top of the (also flat) TS table.  The stones are flat but I imagine a 10 incher could be bent a bit under the pressure of flattening or sharpening, if not properly supported.

   I will disagree with that Philip a bit and say that an edge can be further improved by polishing with the 4000 then 8000 grit "sand"papers.  When applied to a blade subsequently used in one of Philip's planes, for example, it does seem to increase its already magical ability to plane horrible stuff agin' the grain and leave a glassy surface.  Nor am I resharpening this fine edge every 10 minutes, so there.  :-)

   That extra-extra-fine DMT looks interesting.........

   Lataxe

1. 
   Patto | Jul 23, 2007 02:11am | #12

   Lataxe,

   I have a very fine diamond plate (not the one with holes, it just looks wrong) and a set of the little paddle things. Never had anthing better for touching up a forstner bit or an auger than those paddles.

   I dont use them for my carving knives - a small hard arkensaw slip is sufficient because I tend to touch up knives every 5 minutes and the slip leaves them close to polished.

   I live in a pretty dry cliamate so rust is rarely a problem, but I found my stone getting clogged with the oil I had so went back to water with a bit of detergent. The only thing that clogs it now is any wax of the back of the iron, and that dissappears quickly.

   Dave

2. 
   spf | Jul 23, 2007 06:02am | #13

   Pricey?  Depends...

   I looked at two well-known web vendors (LV and WC) for prices on waterstones of comparable size and grit.  Guess what?  DMT continuous surface stones are very comparable to Norton waterstones at the finer grits.  But you CAN pay more for imported waterstones, or pay less for local cheapies. 

7. 
   troys | Jul 21, 2007 08:46pm | #11

   The stones I use are a course and a medium 3-M diamond stone that I think are not made anymore and a 1200 grit DMT diamond plate that is solid steel with a diamond grit surface. I usually use a back and forth motion along the length of the stone for the bevel and a circular motion for the back if I am flatting the back. I do the same on the 8000 grit waterstone for polishing. I have to be careful with the very narrow chisels that I don't gouge the corners of the chisels into the stones. I have been slowly getting better at sharpening with out a jig and I think the diamond stones help with this since they cut very fast although maybe it is just practice.

   Good luck

   Troy

8. 
   Ed | Jul 23, 2007 06:42pm | #15

   I've been using the DMT stones for about 10 years. They stay flat, cut quick, no mess.  They DO wear IME, albeit slowly. 

   I once used a diamond stone to flatten a piece of aluminum.  The aluminum peeled the diamonds off the stone and ruined it in short order.  Lesson learned, and I hope by posting this others may benefit from my error. Stay away from soft metals :)

   Ed