Pretty big problem

[Art Brazee]

Thanks Jerry - it's a new Powermatic. I have had a few problems with new machines, but I expect it's the man - not the machine!

[Art Brazee]

Guys,
Thanks for all the feedback - There is a trend and I was thinking about the whole problem too. I don't think it's the lathe, the tools, or the speed. My lathe is new, I generally turn at about as high a speed as possible, and I've been a woodworker for a long time. My tools are very sharp. The only thing that is left is the man. Many of you have had similar problems to varying degrees and offered what works. I do think it's me. Mike offered, what sounded to me, the best explanation. I'll reply in his thread.

[Art Brazee]

Mike,
You really have offered the most plausible theory. "Instead of riding the bevel glide on the bevel" seems like good advice. I'm a bit unsure of what that means. I've tried less pressure on the tool, but I definitely ride the entire bevel on the work. My tools are not hollow ground, but flat ground - all of them. So, I have a large bevel area.

I often get a burnish behind the cut - you're suggesting (I think) that that is not a good thing. Or, at least something I want to avoid right now until I conquer this problem.

Could you elaborate a little because what you have said rings true? I so wish I had a master turner to turn to as I've found the nuances of turning move difficult than any other woodworking problem (excepting, perhaps, saw sharpening).

Thanks MUCH!

[Michael Stafford]

The best way I can describe gliding on the bevel is to tell you how I start a cut with a tool. First you place the tool on the tool rest without the tool in contact with the wood. Next gradually raise the handle of the tool until the heel is touching the wood. Slowly raise the handle until the cutting edge engages the wood and shavings start to appear. As you raise the tool more the shavings will increase in size and if you rotate the flute the curlies will be spiraling off the tool.

If the tool is sharp it will not be necessary to press the tool very hard. When you feel the necessity to press hard and the shavings change from spirals to chips it is time to sharpen. A sharp tool is one of the main secrets of woodturning and is essential to developing good tool control. Whenever the chips change in character it almost always means that the tool needs sharpening.

Burnishing the wood is not a good thing as the burnish marks can show up in your finish and they are darn near impossible to sand out.

Another dead give away to the fact that you might be pressing too hard is that the tool is too hot to hold at the bevel. If it is really hot you are pressing too hard. One other thing that can happen is that if you are pressing too hard and the wood is getting thin you will experience an almost imperceptible bounce which is the equivalent to a chatter tool flexing on the wood except in this case it is the wood flexing against the pressure of the tool. As you get thinner and thinner with your turning it becomes more essential that less pressure is exerted and sharp tools are used.

Art we all have made these mistakes as we started turning and some of us slower learners (I put myself in that category as I have much to learn) continue to make them. So give the suggestions you have received a try and I hope they help you out.

P.S. With respect to your tools being flat ground you might try rounding off the heel of the bevel a little so that you are gliding on a shorter bevel. It takes very little of the bevel for the tool to ride upon. I used to sharpen my tools on a 12" disc and found that the flat bevel made it harder to control my tool. This is not the case for all turners as many love a flat bevel. I prefer the concave bevel because it makes it easier for me to not ride on the heel. I still round off the heel of a lot of my gouges to reduce the impact and potential bruising.

[Dan Forman]

Art --- If you go to the top right corner of the web page and click on "settings", you can add your location to your profile, and it will show on your posts. There may be a creeker near you who could help you out.

Dan

[Reed Gray]

Well, on spindles, they can flex, more so if you are turning longer and thinner, and if the tailscock has a lot of pressure on it. The ratio here is in the 10 to 1 area, or 10 inch long, and 1 inch diameter will have almost no flex. On bowls, some thing else is going on.

Most likely it is too much pressure on the tool. If you have noticed that the more you clamp down on the tool to eliminate the bounce the worse it gets, this is the problem. Two comments here, neither original:

Hold the tool as you would a bird. Too tight and you kill it, too loose and it flies away.

The bevel should rub the wood, but the wood shouldn't know it.

When turning the outside of the bowl, and the inside hasn't been hollowed out, there is no chance for wood movement/shrink/warp as you turn. As the wood spins, you alternate from cutting up hill/end grain/against the grain, to down hill/side grain/with the grain. This will create some bounce. When you clamp down with your hands on the tool, and the tool rest, this makes the bounce worse, kind of like a car or wagon with straight axle, and no shock absorbers. If you loosen up a bit, you can absorb a lot of the bounce to the point where it is almost gone. It is hard to teach this because it is some thing you have to learn to 'feel'. If you check out my You Tube clip on turning a bowl with gouges (type in robo hippy) you might be able to see what I am talking about. If you are getting the bounce, back off a bit, then ease the gouge in to just nibble off the high spots till it is fairly round, and start cutting again.

With the inside of the bowl, as you remove mass, the bowl/wood will 'adjust' to having mass removed. The same battle of cutting up hill vs down hill is going on. It can flex as you turn, especially if you are using heavier than needed tool pressure. This is why you generally turn the inside/do finish cuts on the inside in steps. Go down an inch or so and finish cut it. Then go down another inch or so, and finish cut that part. You may have to 'blend' the start/stop points with a shear scrape because the wood has moved.

One on One lessons are probably the best way to learn.

A burnished surface is a good thing on a finished product, but not so much so on one that needs to be sanded. The compressed surface is more difficult for finish to penetrate, and it is also difficult to sand out. If the surface is really burnished, again, this is too much tool/bevel pressure.

robo hippy

[Bob Bergstrom]

I find changing the rake angle (less of the bevel rubbing, 1/8" instead of 1/4") will help. If you can make the cut with a minimum of force holding down the tool on the tool rest or with only one hand on the handle of the tool, you are cutting properly. The more down force on the tool rest the more the tool is resisting the cut. Usually it is only a small step, lean or twist of the handle to correct it. Grinding down the heal of the bevel may help. I found the skew much less likely to leave ripples if I took lighter cuts , but also reduce the amount of bevel rubbing. Just enough to stabilize the cut.

[Jeff Moffett]

I've had this issue as well, and the solution for me was opening up the flute of the gouge a little more. I was being conservative and kept the flute closed (around the 9 or 10 o'clock position). I found that if I opened up the flute (around 11 o'clock) I got a cleaner cut with no ripples.

[Jim Burr]

Oops...Mike beat me to it. It's half speed, half bevel. If you ride the bevel with the correct angle, you will cut everytime. If your grind is sharp enough to cut on slow speed, it'll cut on a faster one so sharp is sharp. Given your sharpening skill are up to par, speed, angle and bevel are the keys

[Rodney Walker]

Joining a club is good advice. It will go a long way toward making the learning curve less steep. Nothing beats learning in person. If there's a club near you, it's well worth the time and effort to join.
Rodney

[Dennis Nagle]

I was having the same problem until an old turner who watched me turn pointed out that I was not riding the back bevel of the tool on the wood. Since them, EVERYthing is turning much smoother. I second finding a turning club in your area.

[Reed Gray]

Speed had little to do with it. Mostly it is technique, how you hold the tool as you cut the wood.

The terms 'open' and 'closed' flute always confuse me. Open flute to me is a continental style spindle gouge, and closed flute is a deep V gouge. I always roll my gouges onto the side to cut. This puts the nose of the gouge in a high shear cut angle, and the wing does more of a scraping cut, depending on how heavy of a cut you are taking. This is in part because I hold my tools more level when cutting, whether on the inside or the outside of the bowl. On the outside of the bowl, you can drop the handle, and get the higher shear angle by using the wing. With the flutes rolled more onto the sides, the risk of the wing catching and digging in is 0.

robo hippy

[Rick Markham]

Since, you are a "newer" turner there is always a significant chance that over time your grind angle on your tool has changed. Tool steels work best at specific angles if you get out of their range they really cease being sharp, or dull extremely fast. Personally, I would hollow grind all of my gouges, and make a bullet shaped grind on your skew. By trying to ride a flat bevel you are resting the tool on a single point (where this happens varies depending on your angle of attack) A hollow ground gouge rests on the cutting edge and the very back of the grind, You have two points of contact in a stable configuration and the front one is the cutting edge (making it intuitive to engage the cutting edge on the workpiece.) If you are white knuckling your way through this, it only makes it worse as Reed said! Most shaping cuts I make are controlled with a single finger on the gouge. Presentation of the tool (and the sharpness/proper grind angle) is everything! Good luck!

First I would check all my tools and make sure the angle of your grind is appropriate for what tool steel it is made out of. Then, I would hollow grind my gouges, It will make it easier on you

[Mark Levitski]

Speed had little to do with it.

Maybe not speed in itself. However I am in the "speed" group for this problem based on own experience. The suggestions to up the speed of the lathe are not as important as to guard against moving the tool too fast through the cut. IME this produces what you describe. In this case it IS related to speed, but not directly. Too much tool-advancing speed through the cut can yield the same poor technique issues that arise via other faults in presentation. Slowing down the progression of the tool through the cut, or, alternatively, speeding up the lathe, should help.

[robert baccus]

It seems to me that the easiest way to remove ridges and out of rounds it to apply a tip cut with a razor sharp gouge presented head on. Like a toothpick, flute straight up at high rpm. This allows the tool to cut the high spots and not follow them. Sounds like you are at that point maybe.