In this video, Stuart Batty continues to shows the importance of sharpening.
Transcript
The torn grain will nearly always occur on end and on this mixed grain bull blank, where the grain is running in this direction, the end grain was vulnerable. And as you saw before, when I cut it with a very dull gouge, it tore a lot of the fibers completely out, completely unusable, not fixable with sandpaper in any way at all. The same problem can apply to direct end grain here if the tool is dull.
So I set everything up to be correct technique, speed, stance, etc. But one of these tools is dull and one is freshly sharpened, and we’ll see the result between cutting across with a dull tool first and then taking the exact same grind and style of gouge doing the next cut and seeing the cleaned-up result.
So everything was correct, except for the tool was simply used too much before and has become dull. And as you can see, cutting directly across the end grain, we’ve got torn fibers. To sand this, because end grain is so resistant to being sanded away, will take an incredible amount of time, so we don’t want to have a struggle with that problem. We simply want to cut it clean. Changing this gouge out. Let’s go with a freshly ground one, and let’s see the result from doing the exact same cut.
So here we can see I cut across the fibers here with a freshly sharpened gouge. There’s absolutely no damage to any of these fibers. It’s smooth to the touch other than the texture of the wood. This would just need touching with a bit of 180 grit and above sandpaper to your desired finish. But there’s no repair work needed to do. All that’s left on the surface are tool marks, and those would come out immediately with sanding with 180 grit, maybe even 220.
We hear the term in woodturning “rub the bevel”, and as I pointed out before, this is a misnomer. It isn’t “rub the bevel”, it’s “glide the bevel”. When I place the bevel on the surface but add no extra weight to it, I can get the tool to glide very comfortably across the surface. On this occasion, I’m going to create the cut and I’m going to let my left hand take a little bit of control and pull it into the surface. And what will happen here is I’ll induce bouncing because I’m over rubbing the barrel.
Here you can see the spiral or bounce mark created by rubbing the bevel without letting it collide on the surface. You’ll notice there are almost no marks at the beginning. It takes a little bit of time again when the fibers are compressed to create a little bit of a bouncing wave. Yet the bevel hasn’t yet traveled over them. Once it does, it starts to make the cutting edge, the very nose of the gouge, create a bigger and bigger spiral, so it doesn’t happen immediately, takes a moment of time, and the very middle of the tool is basically out of control.
Now, the one thing about getting a spiral is it doesn’t actually damage the edge of the tool. I just need to go back, be on the outside and start fresh again. Now, the opposite to rubbing the bevel is actually no bevel contact at all. And in fact, it isn’t possible to cut across end grain without bevel support of some kind. It simply will spiral sideways. And the other problem with that, when you take the bevel off and you cut across the face, I’m actually scraping with the very nose of the gouge that’s doing the finished work, so it’s actually damaging the surface fibers. But most importantly, it’ll actually damage the tool. So even if I go back to fix the cut, I need to go back and re-grind the tool. So let’s do that defect next, and then I’ll show you how it’s done correctly.
So you can see it’s a complete mess, and without my left hand there, the tools simply want to dig in and then kick out sideways, so it’s a very poor cut, loss of control, and in fact, it would be almost impossible to make a clean straight line and you would always be tearing the fibers and killing the edge. So what’s happening here is I’m controlling the tool without the bevel. I’m using my left hand as third support, like on a tripod. On a tripod, we always know it’ll stay stable. A wood-turning tool needs the same. It needs bevel contact to be stable, it needs a tool rest and the right hand controlling the tool. The left hand is simply there to add weight and position for the start of this type of cut. So to make it from the edge to the outside without the bevel support, I had to use my left hand with considerable force to push the tool across the fibers, and I could actually feel the heat, the dust being torn off that it was pretty hot on my fingers.
So I know the cutting edge is now dull. If I try to cut across the surface, it probably isn’t going to give me a good finish. So I’m going to go and sharpen the tool. But let’s do one cut and let’s see what we actually do get has a finished result. Go back, we sharpen the tool, see the improvement.
So the tool was definitely dull. It wasn’t completely done, but it wasn’t doing a good job with the finish here.
I can feel the fibers clearly there’s some light tear out on the surface here. And again, this would take a little bit more sandpaper than I would want to have to use to clean this up. So, quick sharpen, one light cut across, and let’s see what we end up as an end result with a sharp tool back to correct technique, not allowing our left hand to do anything other than place weight onto the tool rest position for the start of the cut.
So we’re back to very clean fibers. I can only feel the wood grain, not any torn grain, and I was pushing with about a pound, pound, and a half a pressure to get the desired end result. When it was still before I was pushing with about two and a half to three pounds and with a very dull tool that I used on the very first cut. Well, I can’t remember how much I was pushing with, but it was considerably more, maybe three times four times harder than I just did.
So really important that if the tool is dull, or damaged, incorrectly ground, it must be corrected. And therefore, when I apply the correct technique in combination with all the seven setups, then we get the perfect end result, requiring just a minimum amount of sanding.
See the first part of the video.