Vibration: How to stop it?

[Chris Yarish]

I am a novice turner and I was making a cherry tool handle ~15 1/2" long. It tapers between 1 1/2" and 1" or so. Once I got it round, it began vibrating. I tried lathe speeds between 500rpm and my upper limit (2000 rpm???....not exactly sure the max).

I worked with a skew and a spindle gouge to no avail. I varied the speed and the depth of cut I was making. I also tried steadying with my hand while cutting but is a spindle steady necessary for spindles of this length, or am I just doing something wrong?

[Raymond Overman]

It could be a number of things. If you have too much pressure on the tailstock end, it could bow the workpiece. If you have bad bearings at the headstock or in the live center it could cause wobble. If you are turning the piece very thin or the wood is wet it can bow with the pressure of the tool. If your tool isn't sharp it could be causing you to exert more pressure for the cut which in turn bows the work piece.

I wouldn't say that you should have problems with a 15" piece between centers if it's 1" or more in diameter. At least not in my experience. Sharpen your gouge and take lighter cuts while rubbing the bevel. Hopefully that is all it is.

[Chris Yarish]

Thanks man....I think it may be the pressure between centers.

I actually never would have figured that out. How do you know how tight to push/screw the tailstock into the end of the workpiece?

I am using a live center I think. It's a pointy ended thing that spins with the piece and is on bearings if I remember correctly. As you can tell by my lingo, I'm a novice. Please feel free to correct me if it's not technically called a "pointy ended thing on bearings".;)

[Raymond Overman]

Chris,

Seat the other pointy thing without the bearings on the headstock end (spur drive) with a dead blow hammer before putting the piece between centers. Then bring the tailstock up with the live center and just put enough pressure on it to hold the work piece securely. Don't drive it in with the tailstock. This will help by not bowing the work piece.

[Chris Yarish]

Yep...I pound the spur into the headstock end a few millimeters. I will not put the tailstock end in as tight and see what happens.
I'll report back if it is unchanged.

Thanks.

[Steve Schlumpf]

Chris - just to add a little to Ray's expert advice - when I bring up the live center and seat it into the wood - I always go back before locking everything in place and make sure I can turn the live center by hand. I don't want it to loose but I want to be able to turn it. If I can't - it's seated to tightly and I back it off just a smidge - that's a technical term for 'not a lot'. Hope that helps some.

[Reed Gray]

When I turn spindles, I like to have the headstock end in a chuck. It just holds better, and you don't have to have as much pressure on the tailstock. Now, for the vibration, a rule of thumb is 10 to 1, which means for every 1 inch diameter, you can go 10 inches long, with no vibration. When you exceed this ratio, you can get the vibration, or whipping of the spindle due to its flexing no matter how little pressure you put on it as you cut. This is when you use your hand as a steady rest or use a steady rest as you cut. the other reasons can also cause vibration as well.
robo hippy

[Paul Engle]

As a way of checking the ts to the hs, bring up the ts point to the spur drive's point and make sure the points are dead on, if not the out of round will continue to plague you as you will not beable to get the spindle you are turing concentric with the line between the two points if they do not match up , thus you would be turning " out of round " continusously. If they do not match you will have to shim one or both to get the up and down to align and the side to side by adjusting the ts, you may have to index the ts to get it to repeat the setting once you move it to the turning position. align the ts to the hs and mark a line on the bed and ts, once you have done the align and transfer the bed's mark to a point where you can line up the mark on the ts with the beds mark , for the distance you need to mount the spindle you are turning.

[Chris Yarish]

The points are perfectly aligned. I will be giving it another go this weekend with less tension between centers.

[Glenn Hodges]

The first things I try are use a bigger hammer and masking tape. If these don't work I start looking for the reason why and then try to correct it, but this takes time.

[Steven Wilson]

Chris, you don't mention what lathe you have and how it's mounted. If you're using a minilathe it needs to be firmly affixed to a heavy base.

[Chris Yarish]

I have a General 160 with 6 bolts 5" deep into a concrete floor.
She's parked ncie and tight.

I am more inclined to say that it's set up error or working error and not machine error. I am very green and learning only through books and online forums.

[Chris Yarish]

The first things I try are use a bigger hammer and masking tape. If these don't work I start looking for the reason why and then try to correct it, but this takes time.

A bigger hammer is always the first card of the deck for me. If that fails, I get a bigger hammer.
....a little duct tape is always in order in the aftermath.