any tips for turning air?

[Brian Brown]

I, going to try a piece today that will be slightly out of balance, and has voids. I can usually keep the vibration down to a minimum, but am worried about the voids. In the past when I have "turned air", the tool bounces when it contacts wood vs air. This causes a deeper cutting action where it leaves the air, and contacts the wood, and can cause some increased vibration. It also can cause an uneven thickness in the piece, at the leading edge of a void. Do any of you have some magic way to keep the tool the same depth so the cut is not uneven? Would a pin in the tool rest to brace the tool against help? Any other thoughts?

[Steve Schlumpf]

Brian, I am sure everyone will have something different that works for them, but for me, I find a slightly higher speed and a slow 'feed' rate works best. The higher speed reduces the amount of time your tool is cutting air and the slow feed rate ensures that you do not push the tool forward while it is in the void. Just takes some practice but the key to the whole thing is to take your time and don't push the cut!

[daryl moses]

I agree with Steve, speed and a light touch is your friend when turning air.

[John K Jordan]

Sharp, sharp, sharp! Light cuts! I use my hand to "pin" since tiny adjustments need to be made constantly. I press the tool into the rest with the left hand to keep it stable. I'm careful to support my right arm against my side. When entering a cut from air, such as in square or winged pieces, I like up the gouge if possible on solid wood, slide forwards and backwards adjusting until it is JUST about to make a "whisper" of a cut, then back out and try to hold that same angle for my air cut.

Also, keep the heel of the gouge from rubbing and bouncing on the work. Many people, including me, grind away the or round over the heel and leave only a short bevel, maybe only 1/8" or so. Grinding away the heel prevents burnishing defects on normal work but I find it can help with bouncing on air cuts. And as Rudy Lopez said in a recent demo, don't "rub the bevel" but "float the bevel"!

I don't fret about tiny ripples left on the wings - I just take them out quickly with curved cabinet scrapers with the lathe stopped. Way better than sandpaper.

Edit: And I just read where others suggested higher speed and slow feed rate - absolutely! Of course, that is almost always the key to perfect finish cuts. I turn most of my smaller things at 3200 rpm, other things as fast as I dare. Jimmy Clewes turns up even fairly large winged pieces so fast it sounds like plane taking off. I've seen people in the line if fire slide their chairs over and lean out of the way!

JKJ

[Keith Pleas]

I'm not a turner, but this really sounds like an abrasion action would be better than a cutting action

[Terry Vaughan]

Yes speed should be as high as is safe. Things to try: It is possible to use balancing weights to cut vibration and enable higher speed. A pin in the rest does help a lot to control the tool but restricts movement and forces you to work in small steps. Make sure the tool is sharp and that the bevel doesn't get knocked back when the wood comes to it. Lift the handle very slightly so the bevel is just clear of the wood. Press the tool down onto the rest if necessary, not against the wood. Focus on moving the tool along its planned path, pushing in that direction only.

[Reed Gray]

This can also be where the 'Hold the sword/tool as you would a bird. Too tight and you kill it. Too loose and it flies away.' comes in handy. You don't want the white knuckle grip. That actually makes your tool bounce more. It does take practice to learn to be able to do smooth cuts on open wood forms. Just one hole, not bad. A rectangular bowl, much more difficult, but generally the wings are all the same distance from the center. Natural edge bowls can vary from simple to you've got to be crazy....

robo hippy

[Ken Fitzgerald]

You have gotten some pretty sage advice! Faster speeds reduce your air time.....sharp tools......light cuts........don't be overly aggressive with the feed or the tool hold!

It takes a commitment!

[Brian Brown]

I will try to balance better. I get nervous turning faster because the vibration gets word. Better balance, less vibe. Last time I tried it, my tools may not have been as sharp as they could be. I'll try some of your suggestions. Cover me, I'm going in.

[Ken Fitzgerald]

Brian,

One last thing to remember, as you turn the piece, it will become more balanced. So, you should experience less vibration as you continue to turn.

[Terry Vaughan]

You will find it difficult if the lathe is vibrating. Spin the work fast but not enough to start it shaking.

[John K Jordan]

Just to be clear for the OP: There are two completely different things discussed in this thread.

One is a balanced piece that has air to cut. (for example a square, triangular, or rectangular shape) The other is an unbalanced piece that has air. (for example, a chunk not yet turned round, an unbalanced natural edged piece, or a heavy piece unbalanced by natural voids)
My opinion:
- The balanced piece can be spun very fast.
- A light-weight but unbalanced piece MAY be spun reasonably fast.
- A heavy unbalanced piece cannot, for both mechanical and safety reasons.

JKJ

[Terry Vaughan]

You are right, John. That's why i said as fast as is safe. The faster the piece spins, the easier the cutting, but the greater the potential for it breaking up. Centrifugal force, a dig-in or accidentally poking the tool into the air gap could blow up the piece. A natural void is a warning sign - it's always a weak point, and may connect to hidden cracks or bark inclusions. Cutting the wood too thin away from the edge can weaken the structure. There is always a judgement to be made. The turner always has to keep the piece under review and use caution and common sense (and a face shield!)

[Adam Wager]

This one might be obvious, but I have found it helpful to make sure there is a good contrast between the wood color and the background along with good lighting, especially when the air is near the rim of the piece. You aren't turning air, you are turning the ghost of the wood that used to be there.

[Larry Matchett]

A B C
The principal is anchor, bevel, cut.
The first is the most important. I think John said press down on the tool rest with the tool. Essential. Your too should never ever bounce. Then kiss the piece with bevel of the tool. Once again it should never ever bounce. Then cut. As has been said over and over again light cuts. I too agree as fast as the piece will allow. The faster the piece turns the less time between wood and air. Hopefully you are not turning something that has more air then wood. Stay out of the line of fire and check often for cracks. Wear a good face shield and maybe even a glove on the tool hand. You never know it might blow up. Turning pieces with voids and cracks is not for the faint hearted. Don't mean to scare you but take every precaution.