Sharpening a Skiving Knife
Flat back, low bevel, a burr you can feel, and a strop that knows its limits.
A skiving knife is the one blade on a leather bench that has to be sharper than the others, because it does its work lying almost flat against the flesh, taking a shaving thin enough to see light through, and a dull edge at that angle does not cut. It rides. It skips. It digs in a quarter inch from where it started and leaves a gouge in a strap you spent an afternoon cutting. I skive bridle loops for a briefcase flap pivot bar, and bridle is waxy, thick and stiff, as I put it on my Leather Choices page. That leather tells you about your edge in the first inch.
Video: How to Sharpen A Skiving Knife and Leather Tools, from AlaFrancaise on YouTube.
Read the knife before you touch a stone
One side bevels. The other side stays flat. Find out which before you grind.
Most skiving knives are single-bevel tools. One face is ground at an angle to make the edge, and the other face, the back, is meant to stay dead flat so it can ride the leather like a plane sole rides a board. Philip of Leathercraft Masterclass sorts them by type in a piece on his favorite skiving knives: the angled English knife that works low and suits thin skins, the curved German blade that cuts only in the middle when used bevel down, and the Asian knife with a short blade set across the handle, which he finds harder for a beginner.
In a leatherworker.net thread on sharpening for beginners, a member called zuludog puts the first rule plainly: “You must have the bevel on one side only.” He also says the bevel on many store-bought skivers comes too short and steep, and that it wants to be longer and shallower.
How shallow is where the sources stop agreeing. Jeff Peachey, a book conservator who also makes paring knives and teaches sharpening, recommends the lowest angle the job allows and puts paring leather at around 13 degrees. A leather tool shop’s guide from CÍ Official says 15. One poster in a thread on microbevels took his knife to 20 degrees per side on a guided system. Three numbers. No referee.
My opinion: pick one, write it on a piece of tape on the handle, and stay with it long enough to learn what it does in your leather. Changing the angle every session is how a bevel ends up round.
Flatten the back first
A rounded back is a dull knife wearing a shiny coat.
Peachey calls rounding the most common sharpening error, and says it plainly in his Ten Commandments: “Rounding the bevel, or the back, is the most common mistake in sharpening.” A blade can look polished and still refuse to cut once the two faces meet at a blunt angle instead of a keen one. He admits some rounding always creeps in, so the job is keeping it small.
So the back comes first. Lay it flat on the coarsest abrasive you plan to use and rub it until the scratch pattern runs evenly right out to the edge. A write-up of a Peachey sharpening workshop at the Oxford Conservation Consortium describes that order: rough shaping on a diamond stone, flattening the back, then the edge, working through microfinishing film stuck to plate glass so the surface underneath stays flat.
Flat is the word that matters there. A worn stone with a dip in the middle will put a curve into the back no matter how careful your hands are, which is why Peachey tells sharpeners to use the whole length of the stone and not just the center. Grind on a sagging floor and the cabinet comes out crooked.
Do the back once, properly, and after that it needs only a few light strokes at each grit to take off the burr.
Raise a burr and climb the grits
Do not move to the next grit until the edge tells you to.
Now the bevel. Set it on the stone at the angle you chose, and hold that angle the whole stroke. Peachey’s commandments say to work side to side, parallel to the edge, because it keeps a bevel consistent more easily, though he allows other directions if the angle holds. He wants a lubricant every time, since a glazed stone heats up and cuts slowly, and he wants the scratch pattern checked as you go, with a 10x lens if your eyes need help.
The signal to move on is the burr. Peachey describes it as proof that the two planes of the edge have met, which means there is no flat, dull strip left along the edge. Run a thumb lightly off the back side, never along the edge, and you will feel a tiny wire catching. No wire, no next grit. Stay where you are.
His advice is to climb in small steps, not one big jump. The leatherworker.net member bikermutt07 lays out a cheaper version of the same idea in the beginner thread: wet/dry sandpaper on a flat quartz plate, starting at 400 and working up through 800, 1000, 1500 and 2000, pulling the blade away from the edge, ten strokes a side, then five, then three, checking the bevel under magnification and adjusting. He also says a new blade can take about an hour to train. Believe him. The first session on a factory knife is always the long one.
I learned most of this the slow way. When I started, years before anyone paid me for leather, there was almost nothing good to watch, so it was trial and error, books, and studying how bags in stores were put together. A burr was something I found by accident before I knew the word for it.
Strop, and know what the strop cannot do
The strop keeps an edge. It does not make one.
Peachey’s guide to stropping a knife is the clearest thing I have read on the subject. He uses the flesh side of horsebutt dressed with 0.5 micron green chromium oxide compound, then finishes on undressed calf. He wants the strop 12 to 15 inches long and 2 or 3 inches wide, long enough to hold an angle without stopping and short enough to keep it steady.
The stroke trails. His instruction is to “always draw the blade away from the cutting edge,” so the edge never bites into the leather of the strop. Hold the knife at the exact bevel angle, keep the back flat on its own pass, start with firmer pressure on a firm strop and finish with the weight of the blade alone. He counts strokes, 12 to 15 a side as a starting place, to keep both faces even.
Two warnings from the same page stick. The black streaks on the strop are steel coming off the blade, so stropping is real metal removal and not a ritual. And stropping slowly rounds the edge over, until a mirror-bright knife stops cutting and has to go back to the stones. He also says a power-driven leather wheel makes it too easy to round an edge.
Philip of Leathercraft Masterclass makes the same point from the other end: a factory edge stropped for years can quit responding, and the fix is to sharpen it properly, not to strop harder. Polish on a dull edge is wax on a flat tire.
Prove it on scrap from the same hide
The test is a clean shaving from the leather you are about to cut.
Paper tests and arm-hair tests tell you about paper and arm hair. Take an offcut of the same leather, same weight, same finish, and skive the edge on a hard, smooth surface. The forum makers in the beginner thread suggest working on glass or a flat stone, and in the thread on knives going dull, billybopp points out that skiving is gentle on an edge because the blade meets the surface at a steep angle. Chopping down onto a hard surface is what kills an edge, and another poster there recommends a self-healing mat or poly board for cutting.
A sharp skiving knife pulls a shaving that curls and keeps coming in one piece. A dull one tears the fibers, leaves a fuzzy, stepped surface, and asks for more push than feels right. When you catch yourself leaning on the handle, stop. Pressure is where the gouge comes from.
Bridle is the honest test. The wax and the tight fibers in a good bend punish a blade that drags, which is part of why bridle makes a hard first leather. My opinion: if the knife skives bridle clean, it will skive anything softer, and if it only skives soft leather, it is not sharp, it is lucky.
Once the shaving comes off right, the rest is the cut itself, the taper and the thickness, which I wrote about in skiving and splitting bridle leather. The same sharp edge matters on the beveling and creasing of a strap, where a dull tool chatters the same way.
The case for throwing the blade away
Sometimes the sharpest knife on the bench is the one you bought this morning.
Everything above assumes the knife is worth the hour. Not every knife is. In the beginner thread, zuludog, the same member who wants the bevel on one side, suggests skipping the sharpening altogether and using disposable blades, a snap-off knife or a replaceable-blade industrial knife, and he warns that pull-through sharpeners will never give a skiving knife the long bevel it needs. The poster who asked about a French edge skiver with a crooked bevel got told by more than one member that a new tool can arrive with a bad grind, and one of them said simply to send it back.
So here is the reversal, and I will not soften it. My opinion: for someone skiving a few strap ends a month, a fresh snap-off blade is sharper than most hand-sharpened edges will ever be, and the hour on the stones is an hour the leather never paid for. A carpenter who changes the blade in his utility knife is not a lesser carpenter.
Where that argument fails me is the long taper. A short snap-off blade flexes, and a long skive on thick bridle wants a stiff knife with a flat back that rides the leather the whole way. The Masterclass piece recommends that a beginner start with a good carbon steel knife, since softer steel goes dull sooner but comes back faster on the stone. That is the knife you end up learning to sharpen, because nothing else holds the line.
And if the stone is what you are really avoiding, a new blade will not fix that.
Leather Skiving Knife Set, 2 Pieces: A two-piece metal skiving knife set for thinning leather edges. See it on Amazon (affiliate link).
BeaverCraft Stropping Compound Kit: A stropping compound kit for sharpening and polishing edges. See it on Amazon (affiliate link).
Wet Dry Sandpaper Assortment, 45 Pieces: A 45-piece wet and dry sandpaper assortment that starts at 400 grit. See it on Amazon (affiliate link).
Fiskars 18 x 24 Inch Self-Healing Cutting Mat: A self-healing cutting mat, 18 by 24 inches. See it on Amazon (affiliate link).
As an Amazon Associate I earn from qualifying purchases. A commission may be earned if you buy through this link, at no extra cost to you.
Sources
- Jeff Peachey, “Peachey’s Ten Commandments of Sharpening”: https://jeffpeachey.com/2011/10/18/peacheys-ten-commandments-of-sharpening/
- Jeff Peachey, “How to Strop a Knife”: https://jeffpeachey.com/2012/09/18/how-to-strop-a-knife/
- The Book and Paper Gathering, “Making and Sharpening Knives: A Rational Approach, Jeff Peachey’s Sharpening Workshop Held at Oxford Conservation Consortium”: https://thebookandpapergathering.org/2010/10/10/making-and-sharpening-knives-a-rational-approach-jeff-peachey%e2%80%99s-sharpening-workshop-held-at-oxford-conservation-consortium/
- Leathercraft Masterclass, “My Favourite Leather Skiving Knives and How They Can Improve Your Work”: https://www.leathercraftmasterclass.com/post/my-favourite-leather-skiving-knives-and-how-they-can-improve-your-work
- CÍ Official, “How to Achieve Razor-Sharp Precision With Your Leather Cutting Knife”: https://ciofficial.com/blogs/handcrafters-hub/how-to-achieve-razor-sharp-precision-with-your-leather-cutting-knife
- leatherworker.net, “When you don’t know how to sharpen 101”: https://leatherworker.net/forum/topic/79308-when-you-dont-know-how-to-sharpen-101
- leatherworker.net, “Microbevel for skiving knife”: https://leatherworker.net/forum/topic/82663-microbevel-for-skiving-knife
- leatherworker.net, “French edge skiver, is this going to be a problem”: https://leatherworker.net/forum/topic/90691-french-edge-skiver-is-this-going-to-be-a-problem
- leatherworker.net, “My knives dull right after sharpening” (page 2): https://leatherworker.net/forum/topic/78130-my-knives-dull-right-after-sharpening/?page=2
- Marcellino NY, Leather Choices: https://marcellinony.com/leather-choice/
- Marcellino NY Briefcase Maker (YouTube), “Skiving Bridle Leather Loops for my Briefcase Flap Pivot Bar”: https://www.youtube.com/watch?v=-_r0iX4bJ-M
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