Sharpening Fingernail Gouge

The fingernail gouge is a turner's tool that earns its place on a carver's bench. Look at the edge and you see a curve like the end of a finger, so the corners trail well behind and never dig where you do not want them. Regrinding one means shaping that curve deliberately, and the jig has a numbered setting that does it for you.

Have you ever tried to clean out the inside of a carved leaf and taken a chunk out of the flower next to it? Did the corner of an ordinary gouge catch something you were trying to protect? Exactly that job is what this shape was made for.

Somebody gave me a couple of these as a gift, and like every new tool that comes into this shop, this one went straight onto the machine. The shape was not what I wanted. The fingernail was not deep enough for me, and the slope was too steep for the work I plan to give it, which is foliage and flowers.

What makes a fingernail different from an ordinary gouge

• The edge sweeps back into a curve instead of running square across the blade.
• Turners use them constantly. Among carvers they are uncommon, which is a pity.
• The point of the shape is reach without collateral damage, especially around flowers.
• A jig with a fingernail setting will grind the curve for you, so you are not chasing it freehand.
• The sequence afterwards is the ordinary one, six steps, and the last two are leather and felt.

Where does this shape come from?

The lathe. This grind is standard equipment in woodturning, where a bowl gouge with swept back wings can ride a curve that a square edge would catch on. Turners have been doing it for generations and think nothing of it.

Carvers, for whatever reason, mostly have not picked it up. The shape stays uncommon on a carver's wall, mine included, and the few I own are all recent. I call that a missed opportunity and not a considered decision, because the geometry solves a problem carvers meet all the time.

Which brings up the other thing worth saying. Every new tool that arrives here goes on the machine before it touches wood. Not because makers are careless, but because a maker cannot know what wood you carve, how hard you drive the tool, or whether your hand wants a long low bevel or a short steep one. Factory geometry is where a tool starts, and was never meant as a verdict on anything.

Which jig grinds a fingernail shape?

Mine is the SVD-186 by Tormek, which runs about a hundred dollars and sits on the arm of a Work Sharp 3000. What makes it the right tool here is a scale along the side that runs from zero up to five.

At zero the jig holds the blade square, which gives you a straight edge and leaves an ordinary gouge's slope exactly where it was. Move the setting forward and the jig starts rolling the tool as it travels, and that rolling is what carves the fingernail into the steel.

Seat the blade centrally in the clamp before you tighten anything. Off centre and the curve comes out lopsided, because one side of the sweep will spend longer against the abrasive than the other.

Setting you choose	What the jig does to the blade	Resulting curve	Where that shape earns its keep
Zero, the default	Keeps the blade square to the abrasive	Dead straight	Ordinary gouges that keep their edge
Two or three	Starts to roll the blade while grinding	Gentle sweep	General work where corners still catch
Four, going deeper	Rolls further, and the corners trail back	Proper fingernail	Foliage and the sides of flowers
Five, the limit	Rolls as far as this jig will allow	Extreme sweep	Rarely, and only on thick steel

How far up the scale should you go?

Start at three and look, which is what I did here. At three the wheel starts taking metal off behind the corners and a recognisable fingernail appears within a minute. At four the curve gets deeper and a burr shows along one side, which is a good sign rather than a bad one.

Then five, as far as the jig goes, and I will be honest about the result. There was barely enough steel left to carry a proper slope, and the curve came out less even than I would like. Extreme is available on this jig. Deeper does not automatically mean better.

About the slope itself, the answer is the same as on every tool I own. As low as you can get it. Pressed for a number, somewhere from fifteen degrees downward, and the one on this blade ended up very low indeed, which gives me a long slope that lies down in the wood.

Which way should the wheel turn?

Away from the edge. Stand where the rotation runs off the tool instead of into it. You can work the other side, and the abrasive will bite considerably harder there, which helps when a tool needs a great deal of reshaping.

Standing on the gentler side suits me because eighty grit on this machine is already quick. Barely any weight from my fingers, and the steel comes away fast enough that overdoing it is genuinely easy. You can hear when the tool starts skipping across the paper, which is your cue to ease off rather than push.

Two small habits belong here. Clean the abrasive when it loads up, using one of those rubber blocks sold for the purpose, and take the burr off with a scrap of timber so you can actually see the shape you have made. Guessing at a shape you cannot see is how good steel gets wasted.

Look at the tool between every few passes. That is the whole discipline at this stage and it costs nothing. Lift it clear, turn it into the light, find where the metal has gone and where it has not, then put it back. On a curved edge this matters more than on a straight one, because the sweep means different parts of the edge are meeting the paper at different moments, and the only way to know whether they are meeting it equally is to stop and look.

What are the six steps?

Eighty grit shapes it. Two hundred and twenty clears the coarse scratches. Then three thousand six hundred and six thousand for polish, then a leather strop, then the felt buffing wheel. Six in all, and the last two are where a curved edge finally gets its inner face attended to.

Those two polishing papers are optional and I will say so plainly. Thirty six hundred already leaves a mirror behind it. Six thousand removes marks nobody will ever see in timber, and I go there because I like looking at a finished tool, not because the wood knows any difference.

What I do care about is what comes off the six thousand. Consistent, straight, no second slope creeping in, no rounding anywhere along it. Those four words describe a properly ground bevel, and it is worth checking before you go near any compound.

The machine wants neither water nor oil. Paper alone does everything and the steel never gets warm, which matters more than people realise, because heat is the one mistake that cannot be polished out afterwards.

A word about the rubber block, since it is the least glamorous item on this bench and one of the most useful. Abrasive paper loads up with metal dust as you work, and loaded paper stops cutting and starts burnishing. Ten seconds with the block and the surface is open again. Paper gets run long past the point where it has given up, and then the paper takes the blame.

Taking the burr off with timber is the same kind of small habit. A rolled wire of steel along the edge hides the shape underneath it, so you stand there squinting at a curve you cannot actually see. Draw the edge along a scrap, the wire comes away, and now you are looking at the real thing and can decide honestly whether it needs more.

Why does the tool come out of the jig for stropping?

Depth is the reason. A fingernail curve runs deep enough that the rotation of the wheel would catch inside it and dig, so the jig comes off and the last two steps happen in my hand. Green compound on the leather first, then blue on the felt.

I put the felt straight on top of the leather wheel and work the outside, then the inside, then the outside again. Barely any pressure at any point. Then I go round again, and again, because every time I feel a burr on either face I want it gone before I stop.

Something useful happens while you do that. The felt is soft enough to follow the inner curve, so it puts a tiny slope on the inside face by itself, and on this tool that is all the inner bevel I want. A slip stone stays in the drawer, and there is no extra step to remember.

One more practical note about the jig, because a hundred dollars is real money. It is not a single purpose device. The same jig holds ordinary straight gouges at zero, which is how most of my tools go through it, and the fingernail setting is simply there when a job wants it. Bought only for this one grind it would be hard to justify. Bought as the jig that handles most of the rack, with this capability included as well, the sum looks very different.

So what is it actually for?

Getting inside a leaf without wrecking the middle of the flower beside it. When you are carving foliage, a bloom's centre is usually the part you most want to protect, and an ordinary gouge brings its corners along whether you invited them or not. This shape tucks those corners back where they can do no harm.

Watch what it does in basswood and the geometry explains itself. Its centre arrives first and the corners follow behind, so the tool enters the timber gradually instead of all at once. Nothing catches, and the sides of the pass come away clean. You get a clean scoop where an ordinary gouge would have left two little wounds at the edges, and no burr dragging behind it.

There you have the whole case for owning one. Nobody's carving is transformed by it, and I would never tell a beginner to buy one before the basic shapes are sharp. What it does is solve a single problem beautifully, and if you carve flowers you will meet that problem constantly.

Trying the shape without buying anything has an honest cheap route. Take a gouge you already own and do not much like, set the jig at three, and see what happens. The worst case is that you have reshaped a tool that was sitting unused anyway. Woodcraft and Flexcut both sell perfectly serviceable gouges to practise on, and so does Pfeil.

One aside about the steel, since somebody always asks. This is a Korean blade and I have no idea what alloy went into it. What I can tell you is that it took the shape well and held it, and after forty years I have stopped judging tools by where they came from.

The rest of the course covers every other shape on the same machine. Begin with the straight gouge, because everything else is a variation on what your hands learn there. Then the V-tool, which defeats more carvers than any other shape and has a second lesson for the days it still will not behave.

Bent shapes follow: the spoon gouge, the back bent whose slope sits on the outer face, and a skew bent. Then the large gouge, the micro tools, diamond discs, seven videos on stropping and honing, and the L-bracket I bent myself. Thirteen lessons in the whole course.

My plane irons I still do by hand, on stones, because I genuinely enjoy that half hour. Carving tools are different. There are hundreds of them in this room and they all have to stay sharp, and doing that by hand would eat the days I am paid to carve. You have to be honest with yourself about which of those two you are. Come and learn the whole thing.

Shall we carve?