I have a really beautiful Japanese skiving knife that my daughter and son-in-law bought for me, while in Japan a couple of years ago.
I was using it to thin some leather from a piece where it would blend with a joint, and I noticed it wasn’t sliding through the leather like it had when I got it. My eyes aren’t what they once were, so I looked at the knife’s cutting edge under some magnification, and what I saw just blew me away! The edge was chipped something terribly!
I’m the only one who has ever used this skiving knife and I always handle my tools very carefully, and it has never fallen from the workbench or come in contact with anything other than leather. I even made a leather sheath for this knife when I received it, so it would be protected.
It is possible that the steel used in this skiving knife is not flawed at all, even though it would seem at first glance that the heat treatment possibly left the blade too brittle. This isn’t uncommon in the blade making world, as the outside (what I might call a skin, for lack of better terms) can be a bit too far towards the brittle side, but once this skin is removed, the remaining body of the blade is both hard and resilient.
Ok, so how the heck can I fix this, without spending hours at the water stones, and without using up half a stone? Now this is going to sound crazy to some, but you hold the cutting edge perpendicular to the 1000-grit water stone, and move the blade down the stone. I know someone is cringing just thinking about doing this to a blade, much less with the damage it will do to some water stones, but stay with me here. This is one of the places that the Shapton Glass Stone series of stones really rock (not that they don’t rock all the time), when you have a narrow tool (something like a 1/16″ chisel or the working the edge of a card scraper), that can plow furrows into your water stone(s). The Glass Stones have a much harder matrix that most water stones I’ve used, and I find they do a better job of withstanding these focused pressure situations, without leaving deep depressions in the stones. Ok, back to the skiving knife… I visually check the knife’s cutting edge after each pass on the water stone, so I don’t waste my time, the water stone or the knife’s steel, and continue until there are no remaining chips on the blade’s edge (not a cutting edge at this point, as this process creates a flat at the edge) of the skiving knife. You may be wondering why I would use this technique, rather than working the bevel as you normally do when sharpening. I find this technique to be much faster and very reliable.
Now that the chipping is removed, its time to work the bevel on the 1000-grit, until the created flat at the tip is gone. This will prepare it to be a very sharp blade! This skiving knife has an amazingly acute honing angle, and the handle can get in the way of some honing guides, when trying to work at this low an angle. I decided to use my Kell honing guide, as it could hold the blade for this type angle, even though I found it was just barely able to retain it. What I mean regarding retaining the blade, is the blade would try to pivot ever so slightly during use, even though I had applied recommended pressure with the Kell honing guide. It turns out the back section of the skiving blade has a little taper to it, rather than two parallel edges. I found I had to put strong finger pressure down onto the rear part of the blade, while I was moving the Kell guide and blade up and down the water stones, which kept the blade static. One way to determine if you have actually removed enough steel, so that the back and bevel meet in the perfect “zero radius”, is to hold the blade with the cutting tip facing up towards some lights. If you can see any reflected light from the tip (not the back or the bevel) then you still have a flat on the tip and should continue to remove steel from the bevel. When you reach the point where there is no longer any light reflected back from the cutting tip (and you can feel a small burr all along the edge, from the back of the blade), it is time to shift to your finishing water stone, which should be at least an 8000-grit or higher. I prefer to use my 1000-grit water stone to remove the burr from the back of the blade, as it only takes a couple of swipes, but it really depends on the situation. Now on to the finishing stone, for both the bevel side and then the back.
You should be left with an amazingly sharp tool! I tested my skiving knife on a piece of leather, and it cut through it like it was going through soft butter. This is a wonderful tool that is back in business!
Thank you for reading the article and please let me know if you have any questions or suggestions.
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I thought I’d supplement my last blog with just a bit more info, relating to the honing guides I currently own. I’ve had a range over the years, and those in the photo below, are a fair representation of those.
In the photo, the guide listed as
1. This guide is by Veritas, and was their first version, as far as I know. This one holds the tool via downward pressure, via a large screw and a disc that touches the top surface of said tool. I struggled getting tools perfectly square, but the newer version 2.0 (I believe this is correct) has attachments that aide in this and accurate setting of angles.
2. This guide is the Sharp Skate which has the bronze unit that holds the blades (with the pins removed, the far top on each end, the internal mechanism can be skewed to set positions with pin-holes or possibly in between). It also comes with the black “tray” on which it sits, with lines the blade can engage, to set the angle precisely. The bottom has wheels that run laterally, which is how this guide (and the tool it holds) is moved. This can hold the larger irons for Japanese hand planes, as well as Western tools.
3. This guide is an older Eclipse style made by Record/Marples, and as you can see, it has thicker castings in areas, and a finger-friendly nurled cap to tighten the guide.
4. This is a very recent Eclipse style, replacing my old worn unit.
5. This is the old worn unit (with the rusty wheel).
6. This one is the Kell honing guide (they now have another version that has wheels with a larger diameter, which can also be had as replacements that fit on the earlier units), which has two clear-plastic discs, that make contact with the side of the tool, rather than galling the inside bronze surface of each wheel. There is another version, that does not handle as wide of irons or chisels, but each are easy to use.
There are a range of honing guides on the market, and one that I have on my hit list, made by Lie-Nielsen. Their new guide is made with precision that is not unlike their planes, and there are a number of different jaws for the guide, depending on the tool which you are sharpening/honing. They even have jaws for their skew block plane irons, both left and right available skewed 18-degrees, as well as a 30-degree skewed version for the side rabbit plane irons, and others. This looks to be THE honing guide! Thomas Lie-Nielsen does advise that he doesn’t guarantee it to work with all irons/blades/chisels, as it was made to work with Lie-Nielsen products, but it should work for a wide range of sharpening
I hope this might give a little more insight into some of the honing guides on the market, and even a few from the past. Thanks for stopping by to check out the info, and let me know if you have any questions or comments.
I’ll start this entry by just saying it out loud, “I love chisels”! There, now no one will ever mistake why I have so many from different makers. Haha. I ordered the four piece chisel set (1/4″, 1/2″, 3/4″, 1″) from Highland Woodworking and with the length of time it took to ship from Barr, […]