Episode #6: Sharpening – Part 2

In this episode I talk about sharpening edge tools with curved edges, like molding planes, bench gouges, carving tools and cambered plane irons. If you’re used to using a honing guide you may find honing these tools a little more challenging as most can’t be honed using any kind of guide. You can hone cambered bench plane irons in several of the available honing guides, however, molding planes and gouges are best done freehand. In this episode I discuss the way I do it.



9 thoughts on “Episode #6: Sharpening – Part 2

  1. In the interest of picking nits, a jig *can* be used on one of these blades if the abrasive is the correct shape. By making a fid using the blade in question you can use a jig to sharpen them on the fid, if you so desire.

    • Feel free to pick nits Mike. You are of course correct, you can use a straight jig in the manner you describe. This may be a reasonable alternative if one has just a few simply curved tools. However, if you have a full assortment of H&Rs, carving tools, bench gouges, complex molders, then making a separate specific fid for each tool can be kind of tedious, not to mention finding the one you need when you need it and storing them all someplace. But of course one certainly can do so.

  2. Bob, I’m only getting to this episode now and saw that you have a hand-powered sharpening wheel/grinder; where did you get it or how did you make it?

    • The hand cranked grinder was bought on ebay. They are actually all over but you have to be careful when buying from there as it’s tough to know what kind of condition they are in. The shaft of my grinder is actually slightly bent so the wheel wobbles in use, making for not so smooth grinding, but it works. I’m considering building a different type myself to replace it since I doubt I’ll be able to replace or straighten the bent shaft. If you do decide to look for one, make sure it has the ability to accept at least a 6″ diameter, or larger wheel as this is the size most commonly sold today.

  3. Hey Bob,

    I am just starting to go back and go through your podcasts. The first one I saw some time ago about sawing technique really helped me tweak a few things about my cuts, so thanks for that.

    What kind of a camber do you put on your try plane. I just restored a 137 year old Auburn tool co Try and ended up with a 12.5″ radius camber, I think that works well but I am not sure if that’s a bit to aggressive (having worked with flat blade previously this makes adjustments faster than I am used to so I am not sure if I just need a bit more practice or if it would be a good idea to “flatten out” the arc a bit.

    Thanks and keep up the good work.

    • I’m not really sure what the radius is. I did a blog post on blade camber awhile ago. You might want to check it out here. In the post I talked about an approximate 20″ radius on my try plane. This wasn’t exact though, and honestly I really couldn’t tell you what the radius is. Honestly, radius is probably not the best way to describe the camber because differences in iron width, blade orientation (bevel up or bevel down) and bed angle will all impact the radius for a given shaving thickness. Be sure to read through all the comments in the linked post to understand what I mean.

      For the most part, I camber the blade enough so I can take a full width shaving about the thickness of two to three pieces of copy paper without leaving tracks. The easiest way to accomplish this is to project the iron to the desired depth, mark the edges where they intersect the mouth, and grind the camber to the marks. No radius measurement necessary. I think it’s much more intuitive to do it this way.

      • Thanks for the link. That all makes perfect sense. I have played with my try some more since then, and based on what I have experienced I need to flatten out the camber just a hair

        I will say that squaring an edge is way easier with a curved blade than a straight one…especially if there is a bit of twist. I am trying to figure out how I did it before.

  4. I have an old slip stone. It appears to be loaded with metal. How can I clean it? How can I flatten oil stones or Arkansas stones?

    Thanks for all your posts. This is such an excellent resource!!

    • There are a few things you can try. The first is to soak the stone in some solvent, like kerosene or mineral spirits. Soak it overnight, then take a stiff bristle brush and scrub each surface to try and loosen the embedded grime. Another option is to boil it. Place the stone in a pot in room temperature water and slowly heat it to boiling. You don’t want to drop a cold stone into boiling water or it might crack from the temperature shock. Let it boil for 15 minutes or so and again, scrub the surface to remove any embedded grime. You can add a little dish soap to the water as a surfactant to help loosen the grime as well. I’ve heard of folks running their stones through the dishwasher too, but I don’t think my wife would appreciate that. YMMV :).

      Flattening is a little more challenging. Silicon Carbide sandpaper (the wet/dry metal sanding kind) on a flat surface will work, but it will take some time. You might have better luck with a diamond stone, but don’t put a lot of pressure on or you might dislodge the diamond particles. Let the paper or diamonds do the cutting and just be prepared for a lengthy session if the stones are significantly out of flat. These stones are not friable like man made water stones and do not wear easily. That’s good and bad. Good for sharpening because you don’t need to flatten them near as often as water stones as long as you use the entie surface of the stone. Bad for flattening because it takes time and effort to abrade the stone. After flattening the stones will usually need to “wear in” again. Freshly flattened Arkansas stones have a coarser texture tht will cut faster but leave a less finely finished edge. Just keep using them and be sure to use the entire surface of the stone. After several sharpenings, the stones will begin to get smoother and “wear in”. This is when Arkansas stones, especially the fine ones like the black & translucent, really become a pleasure to use.

      The oil you use makes a difference too. The oil isn’t meant to lubricate the stone, but rather it is meant to fill the pores of the stone and prevent the steel particles from clogging them. I use the standard Norton honing oil on more open stones like India, Crystalon, and soft Arkansas. These stones need a thicker oil to fill the pores and prevent them from filling with steel swarf. For my fine black Arkansas stone I’ve gone to WD-40. I used to use the honing oil, but I think it was too thick and really slowed the cutting action of the stone down because it lubricated more than it filled the pores so the tool merely rode on a thin film of oil between the tool and stone surface. Since switching to the thinner WD-40 for the fine stone, I feel like my fine black stone cuts and polishes better and faster.

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