Turning Archive 2007

Why the chatter while rough-hollowing beech?

Pat Taylor
>I'm new, and I'm wondering if I'm doing something wrong. I was rough-turning a 9" diam. x 10" tall beech bowl blank, with some bark inclusions on my Jet mini with a 3/8" bowl gouge (freshly sharpened) and I was getting this low frequency chatter/vibration, no matter what speed I used. The outside rough-turning was fine, and this problem only occurred with the hollowing. I was using the stock 4-screw faceplate with 1.25" screws (0.75" penetration) and no tailstock at the time.

I notice that the beech is very hard, compared to the maple, cedar, pine, & cherry that I've used before, despite the beech being very wet.

Am I pushing the limits of the motor on the Jet mini? Is the cutting location just cantilevered too far from the faceplate, so as to induce more vibration? Other ideas? Thanks in advance.

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