Video: The Importance of Sharpening

https://vimeo.com/68784527

In this video, Stuart Batty demonstrates the dramatic difference between cutting with a sharp tool versus a dull one — and why technique alone cannot compensate for a dull edge. This is part of his Seven Fundamental Rules of woodturning, where sharpening is a non-negotiable prerequisite before technique even enters the picture.

For our full guide on sharpening methods and equipment, see Sharpening Woodturning Tools.

Key Takeaways

• A sharp tool requires only 1-2 pounds of pressure. If you're working hard, either your tool is dull, your lathe speed is too slow, or your technique is wrong.
• Torn grain cannot be fixed with sandpaper. Sanding removes side grain faster than end grain, making the surface uneven. The only fix is a sharp tool.
• "Rub the bevel" is a misnomer. Stuart teaches "glide the bevel" — pressing the bevel into the surface causes bounce (spiraling marks). The bevel should ride on the cut surface with no additional pressure.
• The "push cut" is a European-style technique where the gouge is pushed around the curve rather than pulled. It produces a superior finish but requires more skill to master.
• Bounce marks come from over-pressing the bevel with your left hand. The fix: use your fingers to pull down on the tool rest, not push into the work.

Full Transcript

The Seven Fundamental Rules

All of the seven fundamental rules that we've developed here at SB Woodturning, the technique is the last to be applied. And although it is a very critical part of getting the wood cut correctly, it doesn't make up for any of the other rules being broken. And therefore we must ensure that everything is set up correctly before we actually cut the wood. So that involves knowing the grain direction that we're securely chucked, that we have the correct and a sharp tool that we have some extra support if it's needed to arrest a set speed and then stance and technique go hand in hand. If you miss any of these out, in other words, you don't check it off, then the possibility is you've created an error even before you've started the cut.

Pressure and Effort

The technique should not involve strength. A couple of pounds of pressure should be the maximum amount of energy I have to put into any cut. If you're requiring more than that, either your technique is incorrect, your lathe is too slow, or the tool is dull. And also, I shouldn't have to fix torn grain. If I've got torn grain, either the tool is dull, the technique is incorrect. You've got to go through the checklist and see if you've made a mistake with one of them. So I'm going to use this particular block of wood as an example that I'm not going to get beat up taking it down to the round. This is a cut that many woodturners don't enjoy doing because they're getting a lot of vibration back to their body through the arms by pushing into the surface and the air as it's revolving, rather than into the wood that needs to be cut away.

Demonstration: Sharp Tool vs. Dull Tool

So I'm going to show you how I'm going to cut this with ease. Then I'm going to cut this piece with ease to shape it. Then we'll show you if I have a dull tool, my technique will not make up for it. So therefore we have to ensure we have sharp tools to make sure it's working correctly. Taking the bowl down to the round was very easy, I was using very little physical strength. I was transferring the cut through slicing away. I wasn't getting beat up and my finish for a rough cut is more than satisfactory. I'm now going to shape the piece and again show the technique is the way to go. Using leverage and not strength and the correct type of tool to end it with the result that we need in woodturning to minimize the sanding and sanding should only be to remove tool marks. It should never be to remove torn grain. If you have torn grain, it's unlikely you're going to be successful sanding it away without going to some extremely coarse grits and also building up a lot more heat in the piece. If you're getting torn grain, either the technique is incorrect, your tool is dull, or your lathe speed is too slow. One of them needs fixing, possibly all of them.

Push Cut vs. Pull Cut

My style of woodturning is based on the English style of pushing the gouge around for the vast majority of cuts.

I named it "push cut" about 15 years ago to distinguish between my style of cutting and the way someone like Mike Mahoney would work, where they're actually using their left and right to pull a tool around to form their shape on the bowl. Push cutting is an ancient style for all Europeans. Nearly all cuts, whether you're French, German, or Norwegian. Your style is a push-cut style. Pull cutting is a more modern style. It does not give the same finish. Push cut, though, requires a little bit more skill to actually master it, but the end result is definitely worth it. So I'm going to show with my technique here how I'm able to use the tool pushing round to give me an excellent finish with no torn grain and never under any physical stress.

Cutting with a Dull Tool

So our technique of push cutting round a side grain bowl where we have to end grain on both sides of the outside of this bowl, plus a little bit of side grain. There's no torn grain anywhere on this piece, and as we can clearly see, it has some spalting in it, so there are some soft areas that tend to tear out very easily. The common problem we have is when the tool is dull, we'll be working harder, will end up with torn grain. And another problem very common to learning push cut on the outside of the bowl is bounce, and that bounce comes from pushing too hard into the surface we've just cut rather than gliding on it.

So with technique, we never rub the bevel. We collide the bevel. There's a big difference. So I'm going to demonstrate with a dull tool, I'm going to create a cut round here. You'll see I've ended up with torn grain and I'm also going to press in with my thumb, and that's also going to create the problem of the bounce.

The Result of a Dull Tool

Then we show you how to eradicate those two problems, very simply. So I was working pretty hard to get the gouge to cut around there. It's extremely dull and it doesn't have to be extremely dull to destroy the fibers. We can see the end result, though it's pretty horrific. This could not be fixed with any type of sandpaper, not even starting at twenty-four grit is going to fix this, because the problem is it's going to sand the side grain away where there's very little damage, much more rapidly than the end grain. You basically can overheat the piece and make the piece elliptical because you're sanding away. Side grain and end grain is going to resist that, so can't be fixed with sandpaper. The only way to fix this is with a sharp tool.

Sharp Tool: The Fix

I'm now going to do the cut with a sharp tool and clean it up. Then I'm going to show you the bounce problem because I didn't actually get the bounce showing up on this because I was using so much force. I wasn't getting any of the rub of bevel. I was just simply having a problem cutting through the piece.

So I've resharpened my 40/40 bowl gouge and showed that the edge is now back to fresh because it has been used too much before, it was very dull. I'm going to take a cut deep enough to get below the torn grain all the way around, but we'll see a substantial improvement in the surface finish with the exact same cut as before. The only difference is the tool is now sharp again. I decided to stop halfway to show you the difference between a really clean, sharp cut and obviously the cut we were getting before when the tool was dull. Here's the torn grain. Pretty much a mess in here. Absolutely no torn grain on any part of this. And remember, the majority of this is end grain, so we are slicing across the end grain, but actually cutting primarily side grain fibers.

The Bounce Problem

So I completed the cut right to the end and then we'll talk about the bounce that happens on the outside of bowls and on many curved surfaces, even flat sometimes where we do over rub the bevel and create this defect. Here you can see I completed the cut. There is no torn grain, I'm left with a slight mark where I joined the two cuts. This mark is above the surface. Unlike torn grain, where it's actually below and deep into the end grain fibers. This would sand off rapidly because it's a high spot. High spots come off immediately when you touch them with paper. When you dig into the end grain and tear it out, then sandpaper won't fix it if it's deep.

So I've set everything up correct, and I'm going to create bounce on the outside through a defect in technique, so it isn't anything to do with the chucking, the tool rest, the lathe speed or stance, and the tool, I've just freshly sharpened it, so it's ready to go. So I'm going to take a cut from the base to the top, cutting the grain in the correct direction. However, I'm going to end up with a very rippled surface and that comes from instead of controlling the tool only with my right hand. I'm going to actually let my left hand get involved, and instead of letting the bevel glide on a surface, I'm going to rub it on the surface. And as we know, the statement of "rub the bevel, rub the bevel" is very common in woodturning. It's a misnomer. They really mean glide the bevel. Rubbing means friction, pressing on the bevel.

What Causes Bounce

And when I do this, you will see the end result and it's not good. I didn't complete the cut because I didn't need to. The bounce is significant. What has happened is as I've started cutting by pushing on the bevel, the side grain of the wood compressed a tiny amount, maybe just a fiber or two.

That means that I've cut a little bit of a wobble in the cut. And unfortunately, the bevel hasn't yet passed that. So when the bevel passes that uneven cut, it starts to make the point of the tool wave more and more. And as we get further up, it just simply gets out of control. This cut cannot be fixed en route. In other words, once I start the bounce, I've actually got to go back behind it and cut below it, and it all comes from simply releasing my fingers.

The Correct Technique

Now you might say, well hey, I put my hand on the top. Well, it's the same effect by having my hand on the top. I'm probably still pushing in with the palm of my hand and creating the over rub of the bevel. So I'm going to fix this cut by doing a controlled cut all around exactly the same. Except for this time my fingers cancel my thumb and we'll see I don't end up with this destroyed surface. This would be extremely difficult to sand up because these are very high and proud on the surface. So I cut all the way around without putting any additional pressure on the bevel. When I held the tool I kept my fingers not just behind the gouge, but above and behind. So I was able to pull down on the tool rest instead of pushing into the work. And what do we have? We don't have any bounce, any torn grain, a controlled cut, and an excellent finish on this piece of wood.

See the second part of the video.