Tuesday, June 17, 2014

A pair of diamond sharpening stones for $4

Always questing for new ways to save a buck, I bought one of those inexpensive (read "cheap"!) generic diamond sharpening stones.

You can buy your own here, for the princely sum of $4.69 free shipping and all. The price on these types of products jump all over the place. I bought mine about 3 months ago, from the same vendor, and only paid $3.70 shipped. Talk about a low profit margin! 

So, what do you get for the equivalent of a decent latte? The stone measures 6" x 2", #300 grit on one side, #600 grit on the other and is actually two thin electro-plated sheets stuck to a 1/4" thick plastic spacer.

I've already used it a bit, so it's looking rather dirty already. It works just fine. As to be expected for less than $5, the quality is a bit questionable. 

It is NOT flat.

The plastic core readily deforms using a moderate amount of finger pressure. A precision tool it ain't. 

I plan to mount the diamond plates to a different substrate, if I can separate them from the plastic core without damaging them too severely.

REALLY simple! Just a little bit of heat from the heat gun caused the plastic core to bow upward...... It turns out that the sheets are just tacked on using a bit of thermoplastic adhesive.

No prying required, so no damage! When the core bowed, the diamond plate practically jumped off all on its own. In the amount of time that it took to grab the camera, the bowing had subsided a bit, but it was fairly dramatic.

The other side was just as accommodating.

So for less than $5, I've now got two surprisingly flat pieces of diamond coated steel. The plates are die-cut/sheared, so there is a touch of edge deformation, but very slight and only towards the back or uncoated side. A few swipes of a file on the back face and they're nearly perfect.

Now...... What should I mount them to?

In the meantime, I put them back to work, using them to flatten the bevel on a Japanese carpenter's hatchet. I had thought that this blade would be laminated, as so many of the Japanese tools are, but this appears to be of a solid steel construction. It grinds like a laminated blade though, sending lots of  sparks when grinding the edge, but very little when working the deeper bevel. I wiped the bevel with some vinegar looking for an obscured lamination line, but no miraculous revelations were forthcoming. I also tried phosphoric acid and ferric chloride, but no love there either.

Something about this steel REALLY tore up the diamond stones, and not just these, but two other diamond stones as well. The hatchet blade has a very hard edge, too hard to file, but still wanted to load up the stone, causing galling of both the blade AND the stones. It felt like it was dragging the diamonds off of the electroplated surface. Very annoying, and I'm glad that I didn't use my good Eze-lap stones or, god forbid, a DMT stone. This hatchet would've eaten a DMT. Expensive! 

As is clear in the photo, these plates will readily rust (I forgot them outside overnight.... Oops!),  so they should be dried after use. Or use WD-40 instead of water as the lubricant. Just to be clear, this blade was hard on my other diamond stones too, not just these ones. The picture makes them look awful, but the damage wasn't actually that bad, just a handful of scratches. 

I mounted the head of the hatchet at a slight angle, to give better knuckle clearance.

I've had hewing on the mind lately. I made an embarrassingly ugly splitting knife, to be used for making fan birds, obviously just a cheap kitchen knife reground to a single bevel. 

Break off the pointy end and mount a second handle, lash everything together, and call it good (enough). The thin blade does an excellent job of cleaving the wood fibers. With patience (and good eyesight!), a 0.25mm thickness is no trouble.

There is another cheap Chinese diamond stone that I've got my eye on......

These are a healthy 200 x 80 x 1 mm, so about 8" x 3"....Big! The same size as the Eze-lap, they have a number of different grits to choose from, and under $20 delivered. Glue it to a stable substrate and we might have something good here.  I wonder how substantial the electroplated coating is?

The Tsuboman Atoma diamond sharpening stones are a thin plate stuck to a machined aluminum substrate. Wouldn't it be nice if if we could make a home-brew version for less than $20?


  1. I've tried to post a few times before but never works.. I got 3 of those chinese diamond stones in grit 600 (they messed up the shipping, and the second stone was bent) and they cut really nice but they are not really flat. I got a 0.05mm flat diamond stone that I use before (300 grit side) and after (1000 side) the chinese one. This way I get nice results.

    1. Tsuresuregusa, hello!

      Give me more detail! Are your 600 grit the large 200 x 80 x 1 mm diamond stones?

      So you use your 0.05 mm stone to flatten before the #300, then a different stone after the #1000, correct? Can you send me links to the stones that you are using? I love this stuff, and am very interested in what different people find helpful. Any new excuse to buy another sharpening stone...... I'm always looking, haha!

      I used Super-glue to stick the small diamond stones to a couple of pieces of (flat) plywood, and they aren't bad. Actually, they are better than some, and VERY cheap! I am very curious about the quality of the Chinese 200 x 80 x 1 mm stones, and would love to hear from someone who has used them.

      Thanks for writing!


    2. Hi Jason,

      sorry the long wait, I was on vacations (technically, still am, but go home tomorrow). Yes, they are the 200x80x1 mm

      I like the quality of them, and they seem to have a consistent grit on the centre of the stone, the sides are somewhat not so fully coated, or at least I have that impression. They do cut fast and leave a consistent scratch pattern. I use one for sharpening with camellia oil and the other one I got for flattening my natural stones, and for that it is even faster and leaves a really nice smooth surface on them.

      This is the japanese stone I use: http://www.ebay.de/itm/400-1000-SK-11-Diamond-whetstone-sharpening-stone-japan-/131285829713?pt=LH_DefaultDomain_0&hash=item1e913ec851

      but in yellow, from other seller, don't know if there is any difference between the golden and the silver, it was the same price.

      The order of flattening irons is the following:
      a) cheap blue diamond stone from amazon to clean rust,
      b) 300 grit of the golden stone to flatten.
      c) 600 chinese grit to clean the scratches
      d) 1000 grit of the golden again
      (sometimes I touch the chisel on flea market stone that I'd say is around 8000, but most of the time...)
      e) strop on wood with green dictum compound

      This gives me a really flat and nice finish. (I could still use a 3000 before the strop but I got that stone in chile... so maybe I get the chinese 2000 to see how they are.)

      My wife's grandparents have a violin making shop and last week I was there and tried Opa's belgian stone for finishing, and I managed to get curls on end grain of ebony... that will be from now on my sharpening standard I think, so I'm looking for a real old belgian — I have a belgian stone from those you buy nowadays with the blue stone on the other side, and they are not as hard and nice as the old ones.

      I'd really like to add pictures to the text but actually I just have an old iphone camera whose photos look horrible, I will try to borrow a better one and get some shots to make things more clear.


    3. Hi Sebastian!

      Thanks for the detailed response. To have (and use!) sharp tools can be a transformative experience, but so few of us are able to consistently get good edges...... God is in the details. I have only 1 Belgian coticule, an old natural blue/yellow that feels VERY nice in use, but is too small and soft for carpenter tools. I love that each of these natural sharpening stones is different in its abilities and strengths, but it makes finding the "perfect" one a great challenge. I would love a nice, old, hard coticule, too! .....And large size.... And cheap!

      I am very close to buying one of the inexpensive 200-80-1mm Chinese stones, and your experiences with them sounds like what I would hope for. I am most interested in the coarse grits, something around #120-#240 or so, and the price is attractive. I have been finding the China diamond stuff to be..... not bad, actually, and getting better. More than a few of the Japanese guys that I read use them as a cheaper alternative to the Atoma stones. The diamond stone that you linked to is what REALLY gets used!

      It is difficult to make an informed decision , when buying these diamond stones. You really need to be sure of the size that you are buying. The stone that you linked (from eBay seller Sakura-pink ) is a perfect example. I have bought tools from him in the past, and he is an excellent guy. His English language skills are not great (but WAY better than my Japanese, haha!), but he is very patient and honest. The stone mentioned is a #400/#1000 grit, full sized 204-65-7mm double sided stone that he is selling for around $35 USD. Other sellers are charging $50-$60 for the same stone. This stone is package for the Japanese market, but is actually made in China. China again, haha!

      The gold color stones seem to be in smaller sizes, 100 mm long and smaller, but I think that they used to offer a full sized one, also? It seems like everyone uses these for stone lapping, then do most of their blade backs using waterstones. Not too many seem to be using kannaban, anymore. I think that Beta-ura will be the new normal, sigh.....

      My camera is my tablet computer, so I can really sympathize with your photo insecurity. I shudder to see my photos compared to what others publish on their blogs. As if my writing isn't bad enough, bad photos too?!! How can others be so good at so many different things? I am envious!

      Thank you for your follow-up,


    4. Hi Jason,

      Yesterday I got a not so cheap Charnley Forest stone from Markplaats, the dutch ebay, to see how it compares with the cuticule... I hope it's a good one, in any case will let you know.

      I also want to get one of those coarser grit stones... but so many tools and not enough money to get them all. I also realized while traveling that I need something like the DMT diafold to take on my trips, my friend's knives were a shame to see and use. Have you tried the chinese version of those?

      My stone is a full size, 200x70x7mm but for a few months I don't see it in ebay anymore. Did I mention that I use it with oil because when I used it with water it rusted a bit and lost some diamonds? I actually like it more this way though, my hands get plenty of camelia oil and wife does not try to kill me for the mess I used to leave in the sink after sharpening.


    5. Yes, please do let me know on the Charnley Forest. I have no real experience with good old European stones, mostly Japanese waterstones, but I have looked at hundreds (thousands?!) of pictures. Many of them are quite beautiful. You need to sharpen anyways, so if your sharpening stone gives you pleasure, more the better, right?

      I have not tried the Chinese version of the DMT Diafold, but when I returned my DMT Duosharp to the factory, they kindly included 2 demo sharpeners as a gift, along with a flat(er) replacement Duosharp. The demos were a credit card size sharpener and a duofold single grit #220'ish. The demos were free, and a nice gesture, but the quality was VERY poor, cheap feeling and lost effectiveness extremely quickly. Nearly worthless. I would guess that these were of lesser quality than their real offerings, intended to be given away, but if I were running DMT (haha!)....... I would NOT want my company name associated with such low quality goods. I don't care for the DMT sharpeners at all (I might be considered an unusually demanding customer however) but they DO stand by their product. That is VERY commendable!

      The point that you make regarding the use of oil is a VERY good one! I was using one of my China cheapies on an axe (fairly soft steel), and it was galling the steel and tearing diamonds from the stone (Diamonds work great for hard steel, but I now only use them on the very hardest metals. The industrial users say that diamond shows poor performance on steel, and will ruin expensive grinding wheels, but this information is slow to trickle down to us recreational users. I want too try CBN one of these days). When I switched from water to WD40 (a very thin machine oil), the stone worked just fine. Even more importantly, it keeps our dirty tools out of the kitchen sink (as you also mention, haha)!

      I talked myself into buying that SK-11 stone from sakura-pink (and a new ryoba nokogiri saw). Yay! More tools!


  2. thanks for the detailed answer about DMT. Will look for a different solution for on the go sharpening then.

    The stone should arrive tomorrow, hopefully. It does look nice on the pictures, that's for sure. The guy from whom I bought has another for sale http://www.marktplaats.nl/a/antiek-en-kunst/antiek-gereedschap-en-instrumenten/m847164637-charnley-forest-wetsteen-slijpsteen-scheermes-beitel-schaaf.html?c=3c1f5dcc18d02a99040ca8de656940d2&previousPage=lr

    Good idea of leaving the diamonds for just the hardest steel. Seems like a very good practice and cheaper too. This weekend need to go buying paint and will get also a cheap carbide stone from the construction market.

    Today another chisel from japan arrived, razor sharp out of the box. It was weird, not a perfectly flat and polished back nor a nice definition of the bevel, but nevertheless perfectly functional. So I asked the seller if it was sharpened by a japanese carpenter and this was the answer:

    "I think that was sharpened by a retired carpenter friend of mine. I really need to record his sharpening method so I do not forget it.
    1. Generally spend time getting the stones flat. We have 2 synthetic coarse one a King 1000 and a natural stone to finish off. We use a plate of glass and an abrasive powder called kongo to get them flat.
    Stones for chisels and planes are separated. Flat stones are the key. The natural one is flattened by using the synthetic stone (no abrasive) which was previously sharpened
    2. Then it is just down to technique. He is 76 and started as an apprentice a 14 with his father. I just tend to round the end"

    I found very interesting how fast they go from 1000 to finish it, and how well the chisel worked. Remembered my wife's grandfather go goes from the grinder to the belgian stone and then to the Violin... I guess professionals have less time to waste getting an overly beautiful edge when you need to bring the bread to the table with the tools.

    With my wife we have almost decided to get a camera (we are really bad at buying new stuff...), so maybe soon I can arrange some pictures



Like all of us, I am figuring this out as I go, so when you see something that is incorrect or flat out wrong (and you will!), let me know. This is a learning process. Real people and names, please. Constructive comments and questions are very welcome, but hate speak/politics are not! Life (get one!) is too short.

Thanks, Jason