What am I doing wrong?

Re: What am I doing wrong?

Roger Dunn

>I don't have a laundry list of suggestions, but try turning as much as you can with the tailstock against the work throughout for extra support and that may help.

Good luck

Re: What am I doing wrong?

Peter Teubel

>The wood may not be uniform in density and will always be in an out-of-balance state.

Re: What am I doing wrong?

Loose Tenon

>Brad,

It sounds to me that you are doing things right. The wood density could be the problem, but I would lower the speed, also. I know the 1442 is not variable speed so it will be harder to find a balance. With a V.S. model, I have the 1642, you can bring the speed up to vibration and then lower it so that it runs smoothly. If you have a friend that has a V.S. lathe perhaps you could duplicate you mounting techniques and see if the problem exists. One final thought, just because it's a new lathe don't rule out headstock problems, I had them.

HTH Loose Tenon

Re: What am I doing wrong?

Doug Leite

>Brad,

I agree with Peter & Loose about the density as I just turned 6 Mango bowls last week and 1 of them was very off balance. The piece was over 30" in dia. so the weight difference was enough that with the machine off, the bowl would settle so that the heavy side was down. Try and check for this by disengaging(losening) the belt and rotating the piece by hand and seeing if it stops in the same place every time.

But I have a question that may help. You say that you turn a flat for the chuck jaws to sit against. What part of the jaw is making contact? It should be the outer shoulder of the jaw, not the bottom of the jaw. This way you get a larger contact diameter that adds rigidity to the turning. If this is what you are doing, then I would either suspect that somrthing is wrong with the spindle, or the imbalance is more then the machine can handle.

Aloha

Hawaii Turner

Re: What am I doing wrong?

Fog Tanner

>If your piece will spin freely, spin the blank over by hand and note or mark the blank at the bottom. Do this several times and chek if the same place (or reasonably close) is at the bottom. If it is, its the wood density and will be out of balance until the bulk is removed. If it stops at different places each time, you have another problem. But, since you only have this on some blanks, it sounds like the wood.

Re: What am I doing wrong?

Bill Hale

>Brad

Run the lathe at different speeds with nothing mounted and be sure the lathe is in balance.

Try not using the face plate. I only use one on very large and in the outboard position.

Start between centers and rgh. the outside and the tennon on the bottom. Turn around in to the jaw chuck and finish.

Make a male tennon and clench tight. Make the tennon short enough so it does not bottom out in the jaws, but close. Make the tennon close to the closed size of the jaws you are using and be sure the tennon angle matches the jaws. You want as much full contact as you can get.

And some wood will never balance.

Good turning and be safe

Bill

Re: What am I doing wrong?

Ron

>I had the same lathe, new, and the same problem. Basically I wasted all last winter trying to figure out what I was doing wrong, knowing it was my technique, even though I'd been turning a few years and hadn't had the problem before. Plus the same bowl would turn just fine on my Jet mini. Finally went around and around with the dealer, who couldn't find the problem, and who assured me it was something I was doing wrong. It ended with them returning my money, and me moving on to a different lathe, which hasn't given me any trouble.

Never did find out what the problem was, but I hope they didn't sell that lathe to someone else.

Re: Taking Bets, Ron?

Mark Mandell - Gone Round In Jersey

>

What am I doing wrong *LINK*

Dennis J. Gooding

>There are several possible reasons for the problem, but one that has not been mentioned is the old "washboard road" problem. You may have noticed that dirt roads almost always develop corregations after long use. These are caused by a strange kind of feedback effect between the bumps that are already on the road and the rebound dynamics of automobile suspensions. What happens is that that a small bump causes the tire to rebound and hit the next valley, digging it a bit deeper. Each cycle makes things a bit worse. The same thing can happen with a gouge when turning a piece of wood that is initially out of balance or that has hard and soft spots around the periphery. Often you can bring the problem under control by making VERY light cuts through the problem area and holding the gouge VERY firmly down against the tool rest to minimize bounce. Another approach is to make a pass with a heavy scrapper to knock off the offending bumps and then return to the gouge to refine the surface. Dennis

Remove the 2 to respond.


http://www.roundthewoods.com/hooktool.shtm

Re: What am I doing wrong

Brad Homman

>Thanks to all for the fantastic input!

Re: What am I doing wrong?

Tug Fork Bob

>I too have a Jet 1442. I always start roughing a bowl blank at the lowest speed. If the lathe initially has no or "not too much" vibration I up the speed to the next notch. Many times the vibration will diminish considerably when I do this. I haven't had enough problems yet to motivate me into adding balast to the lathe so the resonance could be reduced by doing so.

Bob Achenbach