Chatter/vibration in bowl turning

[Greg Wandless]

I have been having quite a frustrating time turning bowls. I get a bowl roughed out no problem. However, once it dries and go to finish turn it I have all kinds of trouble with vibration and chattering as I turn. I've tried taking lighter cuts, resharpening the tool, bracing the bowl with my fingers, etc with no significant improvement in chatter.

Anybody have any suggestions?

Thanks,
Greg

[Lee Schierer]

I am far from an expert and hopefully one of the experts will chime in here. Dave Smith showed me to use a scraper for the hollowing cuts in dried wood and it worked well. Make ure your tool rest is properly positioned close to the work and at the right height. My level of experinece does not allow me to tell you if you are too high or too low.

[Paul Downes]

Greg, I also experianced quite a lot of chatter when trying to turn dry wood. I now do almost all my turning with an assortment of scraper tools. It is very important to keep your tool rest as close to the work as practical. I would love to get some time with Bill Gumbine, but I don't have the time to do this right now.
I did spend some time with a veteran turner who specializes in end grain turning, and was suprised that nearly all his tools were scrapers that he designed himself. This guy is a retired toolmaker. Many of his tools have a relatively small nose profile. He makes them using cobalt/HSS lathe tools that he mounts in a steel handle that is 24"-30" long. This allows him to tuck the handle into his hip or side as he turns and I found that this gives you a lot of control. Let me know if you want more information about these tools. While he has talked about patenting his design, it is possible that he won't mind if I pass on some of his wisdom.

[Jim Becker]

Paul, scrapers are ideal for end-grain hollowing due to the orientation of the grain and the way that scrapers cut. (They do cut, not "scrape" when sharpened and used properly...)

Greg, hollowing dry wood is a little more challenging because the different densities between the early and latewood are more pronounced...and more vibration ensues. Once you have the outside shape of the bowl determined and executed and you have the piece reversed, try turning the inside as "steps". This provides more support for the fibers, especially near the rim since once you have it cut down you don't go back to it. The steps consist of hollowing only part way and then "finishing" the rim and down about an inch or so to final thickness. When you are happy with that, you work on the next inch or so, taking a little out of the middle if necessary for clearance. Don't go back to the part you did first with the tooling other than that little bit right before the new step for blending. For some objects, you may still need to use a bowl steady to keep flex and vibration to a minimum, especially when you go to 1/4" or thinner on your walls. Scrapers will not solve this problem...you'd need to use the same relative techniques as with a gouge, but making your blending and finishing cuts with a scraper is just as effective as a gouge. All this assumes you're turning a blank in face-plate orientation, not endgrain which is a whole 'nuther thing.

If you can get some "mentoring" from a member of your local AAW chapter, I think you'll find this easy to overcome. Another pair of eyes can often spot things that you might miss in your own technique, etc. That's one of the best reasons to take a training seminar...it really can make a difference in your turning!

[Paul Downes]

See, I told you I need some lessons!

[Anthony Yakonick]

When turning brake drums at the day job we wrap the drums with heavy "rubber bands" to stop chatter, it will work on wood also but then I NEVER get chatter ;) :D