Sharpening on hollow stones

Someone emailed me as a result of my earlier post and said that if a stone hollowed through constant sharpening of the bevel of a tool’s cutting edge, how do you then hone the reverse flat side of the tool blade without creating a round face on what must be dead flat. That’s a good question. I had been working on the next stage of my challenge on sharpening methodology when I received the question and so my answer is here:

One answer is keep a second, superfine grit stone and use it only for flattening. This stone will still hollow (unless it’s a diamond plate), but only at a fraction of what it does when you hone the bevelled side of the tool. The other answer is to never hone the reverse side once it has been flattened and polished which is what I do. The reverse, (large flat surface) of my edge tools such as chisels, planes, spokeshaves and so on are lapped flat and then polished through refining stages to a mirror finish. This face never actually wears away. Remember it is not the bevel or the flat face that wears, but the very cutting edge. And even this is more a matter of edge fracture rather than wear. The finer (smaller) the edge the greater the edge-fracture because of the lack of back support. The reason we work so heavily on the bevel more than the flat is because it’s so much smaller than the whole of the flat face and therefore easier to maintain. We then move the whole bevel along the length of the blade until we remove the fracture on the very tip. The flat face is still highly polished and can be maintained in its polished state in the next stage in the sharpening process, which is honing on the strop.

Lapping the flat face of all the edge tools is critical to flatness straight off and this is something most woodworkers accept. I usually use my diamond stones for this, as they stay dead flat and wear so minimally I cannot detect any discrepancy resulting in roundedness. From here I go to a dead flat granite tile. A manufactured granite slab would of course be better, but it’s beyond the reach of most woodworkers when they are trying to get on with the job. I recommend that you take a straightedge into Home Depot or B&Q and look through the granite tiles until you find a flat one, or you buy a piece of thick plate or float glass around 5” wide and foot long. This will hold abrasive papers and will abrade the flat face of the edge tools dead flat. I usually work from 150-grit through to 1500-grit and then further polish the face up to the edge with abrasive car polish. In a few minutes my chisel is flat enough up to the edge and polished enough to give the surgically sharp tool edge I need for all of my work. From there I can work on the bevel in the usual manner, regardless of whether I use stones or plates. Here are the steps I use:

 

Here is a drawing of the shape of a well used and well worn whetstone (also known as oil stone natural stone, honing stone, Arkansas stone, India stone, carborundum stone, Japanese water stone, Norton stone and several more) of old. This is a stone used by working craftsmen and these are the ones I saw on all of the workbenches in the workshop where I grew up. No one ever flattened their stones that I ever knew and yet the men I worked with always had pristine sharpness that matched or exceeded what we have today.

 

 

 

 

From this point on it’s up to you what you do as to stone choice. They are all abrasive and they all cut steel. All of them work for woodworkers but some cut steel faster, resist wear more and they will all have different qualities to give you a sharpened edge.

I actually use diamond plates as I have for well over a decade. I recommend them because the stay flat, cut fast and last a very long time. I anticipate a diamond plate from EZE Lap or DMT (3″ x 8″) will last me for personal use about 20 years. Here at the school, sharpening 10 sets of chisel throughout the classes as well as ten planes, ten spokeshaves and other tools including all of my own every hour or two, they will last about 5-10 years.

For the bevel

Here is my preferred method. It’s not the only way, but it’s the fastest of all I know, apart from machine sharpening in commercial grinders, which no one has access to in general.

I have three 3″ X 8” diamond plates in a row, Coarse (250-grit) on the left, fine in the centre (800-grit) and superfine on the right (1200-grit). I always go through every grit from coarse to superfine in that order. It’s important to maintain not restore. I abrade until I remove all previous polish and get down to the cutting edge to remove all dullness and edge fracture. I then go to through the next grits until I have an evenness on the entire convex bevel. You can push from the 30-degree angle and as you push forward gradually drop you hand at the far reach of the sharpening plate to cause an elliptical convex bevel. This will accomplish the convexing you want.

 Strop

Now move to the strop. I use split cowhide, rough side uppermost, glued to a flat board 3” x 10” long. I charge the whole surface of the leather with buffing 15,000-grit compound. This polishes to the ideal level I need for most of my everyday work. Sometimes I go to higher levels and for this I have a square strop that can be flipped for 3 different grit size up to 25,000. The 4th side has plain leather for stropping without compound, to remove any burr from the edge.

The carrier fits in the vise and has a stop at each end so that I can pull the tool against the strop and the strop remains in place. The strop itself is not clamped by the vise but simply enclosed on the two long sides so without loosening the vise the strop can be lifted out, flipped and used with the different grit abrasive compound.

This is a long answer for a very simple solution. Don’t be put off. It takes minutes to do.

 

Pictures tomorrow

19 comments

  1. Ronald Jones says:

    Paul, Thank you for this post on sharpening with hollow stones and sharpening with convex bevels. When I first learned about this method from Steve Branam’s blog, Close Grain, where it is referred to as the Grimsdale method, I was fascinated and perplexed why more woodworkers were not using it. Sharpening is a gateway skill that one needs to learn and become comfortable with quickly or else all other woodworking is difficult, less enjoyable, and at time dangerous. I am still a novice as I have very little time to work on my skills with my day job and family responsibilities, but I feel that I would have progressed more quickly if I did not listen to the flat stone, honing jig, and micro bevel crowd from the beginning. Sometimes I think woodworking suffers from the influx of too many types with engineering backgrounds where precise tolerances and measurements are critical to function.

    I currently use 2″ x 10″ oilstones for my sharpening and begin with the chisel or iron held around 30 degrees and dip my hand down as i move down the oilstone and lift it back up to 30 degrees as I return to beginning position. I find this works well in most cases, except on wider irons. For those irons, I have to skew the blade, and it takes me a bit longer to turn a burr. I feel I should have opted for wider stones from the beginning, but I will make do since I know craftsmen of the past likely got by fine with 2 x 8 and smaller oilstones.

    Your blog is very refreshing and I enjoy each post particularly when you share incites such as these that are are critical for new woodworkers to understand.

    • You say “I was fascinated and perplexed why more woodworkers were not using it”.
      Well me too!
      Not only that, but downright hostility on woodwork forums, except for the regular emails and messages from those (probably not wishing to go public) who appreciated the rounded bevel way.
      2″x10`’ oil stones for me, but I might have a go with the 3 diamond pads as per Paul’s description. “It’s important to maintain not restore” is the key.

      I was the “Grimsdale” by the way. It was my forum user name but I’m back to being Jacob now.

      • Thanks for this, Jacob. You can actually get away with two plates if it is a cost factor. Skip the middle one. It takes just a bot longer. The coarse is super critical though. A 2 x 10 will work but I like the extra width of 3″.

        I would never be without my diamond plates now.
        Paul

        • Although I’m a woodworker, this reminded me of when I was learning to make bread 20 years ago, I was immediately sold a book and a bread maker, on a holiday in the country side in France and after a few glasses of wine, an old baker showed me how to make bread with just water, salt and flour, any flour for that matter, the rest was history, I know make the best bread in the world with water, any flour, salt, forgot to mention the guy didn’t have an oven, so the bread was baked on a stove, oh, and without yeast!!, the next day he showed me how to make my own yeast! it does take some time but it worked, so in essence what Jacob and Paul are saying is that sharpening is like baking, it has always been around! but we have just forgotten how to do it, or shall I say made to forget! so that we can spend our money buying mixers and bread marking machines. As soon as I saw Paul using it at a show last year I realised that I was conned, I started using my lovely japanese stones quite roughly, my blades shone, my bevels sparkled and my guides gathered dust! everything made sense, my experience in bread making helped steer me in the right direction and I can say now that I really enjoy sharpening, Gentlemen I thank you!

    • The reality is there is no difference in the end result at the cutting edge between the micro secondary bevel and the convex bevel, but there is in terms of speed and strength so I go with what I know. I named it “convex bevel” in my book because I wanted a definitive name for it to take away any confusion.

      2×10 stones work but I find them quite narrow, but there was a reason for narrow stones too and we should dismiss the practical element. They preferred narrow stones so the blade, cutting irons could over hang with plane irons Planes and chisels are of course the most commonly sharpened of all tools, especially planes. With the cutting iron overhanging, the stone hollowed only one way and though it became concave along its length, it remained square and straight across the whole width so I didn’t ‘dish’ as such, which would of course create problems because left uncorrected it would in fact worsen, ultimately resulting in a rounded chisel edge rather than straight.

      Best for now and thanks for relying. It is important.

      Paul

  2. Steve Branam says:

    Thanks for the reference, Ronald! And it was indeed Jacob’s method I was referring to, where he had posted it on woodworking forums and defended it against much derision and hostility.

    One thing I like to remind people of is that others have used a variety of methods, and all are able to get their work done. What is the “ideal” method? Does it matter? If the method you are trying is not working, try another. Just the act of experimenting with different methods and different abrasives is training the hands to the task. Eventually, every method you try will get better just from the increased practice. But it does take the discipline of putting the time in to develop the skill.

      • Steve Branam says:

        And I just ordered your Woodworking 1 & 2 with full DVD set from Lee Valley, because we are clearly on the same wavelength! I’ve recently been enjoying Jim Kingshott’s videos, so it will be interesting to compare and contrast techniques. I always enjoy learning another way to do something, because having multiple approaches increases my versatility and problem-solving ability. You never know when one of those techniques is going to be just the thing for a particular situation.

  3. This is exactly the case I am trying to help others resolve. I want people to develop skill, not spend their time following legalistic processes and programs that only avoid developing true and substantive skill. In an hour someone can freehand their tools in three or four hours of consistent resharpening sessions over a week or two they have it for the rest of their lives. The training wheels are off at last and you can swerve and glide and fly. Let me expand a littler; Did you know that you probably cannot tell the difference between a sharpened angle of 25 to 35 degrees for instance, or that when mortising it’s best to add a slight micro-bevel and alter the bevel from 30 to around 35-40-degrees, temporarily, or if paring a veneer yo may want an angle to 25-degrees or go the opposite extreme and change it to 40-degrees. Guides are fine to start, they help get momentum and feeling and feel for the angle etc. The freedom of free-hand speeds up my work and I don’t need the guides at all and I can make alterations of angle-to-task quickly and much more efficiently. That development in growth was critical for me in many ways and was indeed required of me. I saw that at first as perhaps oppressive, but once I was on the other side I was set free. Many engineered products hold us back and defy skill building which then substitutes for the freedom I have enjoyed now for over 45 years. I didn’t have the www so that wasn’t an issue. I was shown only once how to sharpen a chisel, and that was much less than I have explained in my blog releases. I will put up a youtube video showing my techniques one of these days. To simplify it for others. A 1″ wide chisel from dull to super-sharp for surgery is under a minute. A plane iron about 1 1/2; + reloading and setting of course.

  4. Norbikahu says:

    I have tried most of the recommended sharpening techniques available on the net and in books. I am a complete amateur, so I struggled a lot with benchgrinding, honing guides, flattening stones, abrasive paper etc. I was afraid to hone freehand fearing a rounded edge.
    When I saw Paul’s technique it was a liberation. I still use a honing guide to establish an angle on a coarse stone, but that’s it. So all I can say is keep on practising freehand sharpening and the skill you gain will make up for all the sharpening jigs you don’t really need. It is also a lot faster, so you are more likely to hone when you need it.
    Remember the first violin (that I know of) was made in the XVI. century with most probably razor sharp tools, and I am quite sure that those luthiers didn’t have extra flat stones or sharpening jigs, and the same holds true for their planes. It is unlikely that their planes were lapped on a granite plate. There is no substitute for skill.
    Thanks.
    Norbert

  5. Ed says:

    I may have answered my own question: Yesterday, I tried to flatten an old Stanley spokeshave blade using just the diamond stones. I worked for a very long time and did not get it flat on the coarse stone. I moved to sandpaper on a flat plate and made much better progress. I then went through all the grits in sandpaper. I think the lesson is that, with sandpaper, you can change to fresh paper to keep the cutting aggressive and by going through all the grits, rather than just three, you can get rid of the various scratches more easily. I suppose I now wonder why the 3 diamond stones are good enough for the bevel, but even with my limited experience learning your technique, they certainly seem to be good enough. Thank you again for sharing your methods with us. A little more practice and my tools will be sharp enough to work on the projects.

  6. Фёдор Медрин says:

    Hello Paul! I badly know English and did not understand such moment. How often do you have to change diamond plates on new one?
    How long does one complete set of diamond plastins work?
    With kind regards Fedor.

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