Chatter While Turning

[jd420214]

Ive turned a few wood pens with no problem but I just started with the Acrylic pens and while turning I will get some chattering from the blank I have always been able to clean them up and I,ve tried things but nothing seam to get ride of it one pass is good then it will do it the next.
I have evrything nice and sharp but I still get it.
Any help would be greatly appreciated.
Dave

 

[lorbay]

Speed and tailstock pressure can cause this.

Lin.

 

[low_48]

What chisel, rpms, using a mandrel? Very high rpms, very sharp skew, slow feed. Turning between centers will work better than with a mandrel since the distance between the tailstock and headstock is less. If you are using an adjustable mandrel, shorten it up to do one blank at a time. Less flex in the mandrel if it is shorter.

 

[Ted iin Michigan]

Sharpen, sharpen, sharpen.

 

[KenV]

The dreaded Bzzzzzzz says you are taking too big a cut too fast with a more brittle material. Faster speed and much slower feed.

And SHARP SHARP SHARP

 

[magpens]

I believe that the surface of some acrylics can heat up, melt, and stick to the cutting tool in the short time they are in contact. Just my theory and I don't know what to do about it.

 

[Tom T]

All good comments above. Once I was using my tail stock for all turning and the dimple in the mandrel end and the tail stock point got groves and out of round. Had to take a very fine diamond one file to the point of the tail stock and make it round again. I then switched to a mandrel saver in the tail stock. I am sure some of our IAP venders will have that. I also learned to shorten Mandrel mentioned above.

 

[Sylvanite]

I believe that chatter comes from one of three sources:

1. The material flexing,
2. Tool movement, or
3. A dull tool (rubbing rather than cutting)

Does the chatter happen in the middle of the blank but not at the ends? If so , then the material may be flexing

Are you getting out-of-round or non-concentric cuts? Does the problem happen at high turning speeds more than low speed? Can you feel the chisel vibrate? If so, then you may have tool movement. Try to cut with axial (longitudinal) pressure rather than radial (inwards) pressure.

Does it squeak when you cut? Does the blank get warm when you turn? Do you get dust rather than shavings? If so, your tool may be rubbing when it should be cutting. Keep the chisel scary sharp (hone the edge when you feel you need more pressure to cut). If you're scraping, make sure you have a burr on the edge.

I hope that helps,
Eric

 

[larryc]

I too have noticed this chatter and I believe it is a result of poor adhesion between the tube and the blank caused by little or no glue at one end of the blank.

If you turn the blank end for end on your lathe and you still get the chatter at the same end of the blank I believe that is the cause.

I don't think there is any reason to reject the blank because there should still be enough adhesion to hold everything together.

 

[jd420214]

Thanks everybody I,ll try the suggestions my new lathe decided to go nuts last night so I,ll have to revert back to my shopsmith for awhile.
Dave