Getting a lot of vibration when turning...

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M

mbellek

Member
Joined
Jul 18, 2007
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177
Location
Circleville, OH, USA.
Hello everyone,

I don't know if any of you remember me, because I haven't been around in a while... But I'm having some trouble and I knew this was the place to come for help!!

So for some reason, I'm experiencing a LOT of vibration when I turn. The lathe feels steady, but the wood jumps like crazy and I'm breaking a lot of wood. A LOT of wood.

We're talking about spindle turning here, not mandrel. I have a regular drive center on my Jet mini (the one that came with it) and the live center that came with it. If I'm turning an 8" spindle, which is usually what I start with, it'll be worst in the middle. The projects that I do are relatively small, so it tends to get worse as my wood gets thinner... My finished work will be as narrow as 3/16" in diameter. My head and tail stock line up just right, and I'm carefully centering the wood....

Any ideas on where to look next for trouble-shooting?
 
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Hello Melanie ..

To my barely trained eye, it sounds like you are putting too much pressure on the spindle with the tailstock.
With the lathe off, engage the tailstock (live center) firmly so it dents the end of the blank, then back out "a hair's breath" so there is not as much pressure .. then when the lathe is on, make sure the live center is spinning as fast as the spindle .. adjust the pressure a tiny bit until the live center spins (start with enough pressure that it is not quite fully spinning then move the pressure up a little) ..

good luck
 
When does your vibration start?

As you turn the 1" square, or when you are close to finished dimension?
What is your speed (rpm)? Do you change it, as the piece gets smaller?
Can you feel any movement in the headstock (left to right, up and down)?

Mechanically, could it be your headstock bearings?

Do you have any kind of a chuck available, so you could see if it changes with the "threads" vs. the MT?? Also, a chuck is easier to grab to try to wiggle.
 
I don't believe there is enough information in your post to really pin down the cause of the vibration. Do you have a woodturners club in your area? If you do, someone there will come to your house and watch what is happening. Or do you just know an experienced turner? Good luck.
 
Originally posted by Rifleman1776

I don't believe there is enough information in your post to really pin down the cause of the vibration. Do you have a woodturners club in your area? If you do, someone there will come to your house and watch what is happening. Or do you just know an experienced turner? Good luck.
Click to expand...

I know. That's the idea... I've checked and done everything I know to do. I live out in the boonies and I'm a primarily self-taught turner (except help I've gotten on here).

Originally posted by ed4copies

When does your vibration start?

As you turn the 1" square, or when you are close to finished dimension?
What is your speed (rpm)? Do you change it, as the piece gets smaller?
Can you feel any movement in the headstock (left to right, up and down)?

Mechanically, could it be your headstock bearings?

Do you have any kind of a chuck available, so you could see if it changes with the "threads" vs. the MT?? Also, a chuck is easier to grab to try to wiggle.
Click to expand...

I do increase speed as my wood gets smaller, but lately that doesn't seem to make a difference. It looks like my tools aren't touching my wood when I turn, if that makes sense.

Generally I start out on 1800, then move to 2630 as my work gets smaller, and then go to 3975 to finish. Right now the vibration is starting almost immediately toward the center. Where my tools will cut smoothly toward the headstock, they'll make a loud shrieking sound and cut very roughly toward the center.

I can't think of a single thing that has CHANGED though... I think I'm doing everything the same way I've always done it.

And no, unfortunately I don't have any threaded chucks.

Jeff-in-Indiana ~ Your theory has the ring of truth... I'll have to try varying the pressure applied by the tailstock.
 
Obviously it could be many things and I am sure you have trouble shooted. As someone said, there is not enough information. Can you send a pic of your lathe set up and also a pic with your turning in place? Have you checked that nothing has become wedged under your lathe to cause a vibration at higher speed? What wood are you using, perhaps the wood itself isn't the type that can be reduced to 3/16th without vibrating?
 
With lathe off, position the toolrest so the end of it is JUST TOUCHING the wood, in the center, when you have been experiencing the vibration.

Turn lathe by hand, does the wood continue to JUST TOUCH the toolrest, which has been locked in place, or is the wood moving back and forth, changing the distance to the toolrest (which CAN'T move). IF the wood continues to JUST TOUCH when turned by hand, turn ON the lathe at its slowest speed. IF it now is vibrating, adjust your tailstock pressure (less pressure) WHILE THE LATHE is RUNNING at SLOW speed. Did it help??
 
I believe you are experiencing "spindle whip" and a spindle steady is required. These are available commercially or you can make your own from In-Line skate wheels...

Turner's who make long stem goblets will often use their left hand to support the turning while they use the skew in the right hand...

Your 3/16" turning fit the bill...
 
Melanie,

All the suggestions are good, but you have been doing this a while without difficulties, so I am assuming SOMETHING changed. Last night, as I was turning, I thought about you. DId you just get (or start turning) a special TYPE of wood, that may have a "warp" that appears when you get down close to your finished diameter?? (Again, my test above would identify this problem)
 
Melanie,
I agree with John about the spindle whip. A long slender spindle will try to climb over the tool because it is too flexible. Very sharp tools and a light touch may help some, but supplying some form of support, even if it is your hand, will to wonders. That is what I had to do when I turned some long slender wands.

Paul in AR
 
Melanie,

Another thing to consider is that as you thin down the stock your tool angle changes if you do not adjust your tool rest. Another possibility is that if you rub the bevel while cutting near the headstock then twist your body to the right to cut away from the headstock rather then sort of shifting your center of balance to the right, your tool angle can change. In either case, you may have stopped supporting the cut on the bevel.

If you stop supporting the cut on the bevel you can get all sorts of chatter and scary stuff.
 
Sorry for the lag in response time -- my work schedule often prevents me from turning or even thinking about it for days at a time right now.

Most of the wood that I turn is dymondwood... It's happening with any and every kind of wood I turn, except when the wood is shorter than 6" or so.

I'll try touching the tool rest to the wood when I do some turning later on today, and also some of the other suggestions (adjusting the tailstock pressure, adjusting the height of the tool rest.

I only have the one live center -- just the one that came with the lathe -- is there a way to tell if that is the problem?

Sometimes there is so much vibration that thing which tightens to hold the live center in place will actually come un-screwed and then when I turn the lathe off, my live center is still spinning... Does that mean anything? That doesn't always happen, but occasionally it does.

I don't know that buying or contructing a contraption to steady the wood from the other end would help, since I've not ALWAYS had this problem... As ed4copies rightly points out, this is a NEW development and I've turned successfully at the same speeds, the same diameters, and with the same materials with the same lathe in the same setup for several months.

Again, I hope everyone who is telling my I haven't posted enough information understands that of course this post is not me asking you all to solve a riddle here. I'm just asking for DIRECTION in trouble-shooting, not mind-reading, obviously. What to check and how to check it, you know?

I appreciate all the patience and suggestions, and I'll post back with answers to some of the suggestions later today! :)
 
If you answered every question before we asked it, you would have solved the problem and not need us. It's hell not to be needed!!

Thanks for letting me assist.

NOW, back to "Problem solving 401 - the graduate course!"
 
Hopefully just a typo Melanie, but you want to rub the bevel of the tool on the wood while cutting, not the tool rest. Adjust the tool rest so that it is comfortable to rub the bevel with the edge properly placed on the wood.
 
Melanie, Part of my job in the real world is finding problems and fixing them. In your last post you mention something different happening with the live center. Without being there to see it for myself, this would be a red flag to me to start with the live center.
No real reason other than it is the next thing that is not working the same as before. Obviously something changed. possibly lost the bearings in the center or something.
 
Well, I've only been turning for about an hour today, but it seems that ed4copies might've been right -- applying less pressure with the tailstock seems to be helping the problem. I'm getting smoother cuts all along the length of my spindle, but I have not gone down to a thin diameter yet.

Holmger ~ I'm not sure what you think is a typo? I do think my tool rest was a bit low as well, especially after my work got smaller, I was not always adjusting my tool rest to compensate for the fact that the work is higher up -- or at least not compensating enough.
 
Originally posted by Daniel

Melanie, Part of my job in the real world is finding problems and fixing them. In your last post you mention something different happening with the live center. Without being there to see it for myself, this would be a red flag to me to start with the live center.
No real reason other than it is the next thing that is not working the same as before. Obviously something changed. possibly lost the bearings in the center or something.
Click to expand...

I think you're right. But I think what was causing a problem with my live center coming loose is that I was putting too much pressure on the wood with the tailstock -- causing the tailstock to vibrate and come loose?

If I'm still having problems after today, I'll try a new live center.
 
Alright, so I've turned a couple of my tiny spindles today, and, while I've got a LOT less vibration, I'm still experiencing *some* but its manageable. I think I will try a new live center, and hopefully that's all that's off.
 
Melanie,

Perhaps as you have developed as a turner, you are making your spindles progressively smaller in diameter. You may not even be aware of it (unless you caliper each one). But that could be causing your "vibration". IF so, you have to develop a "grip" on the tool that allows a finger or two to support your spindle. This will dampen the vibration and put a new meaning into "fear factor" for a while. Nothing like a nice sharp skew separated from one or two of your fingers by a tiny piece of wood, THAT YOU ARE CUTTING EVEN TINIER!!!!!

Ain't this woodturning FUN?????:D:D:D
 
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