I'm new to pen turning, have turned about 15 pens in the last two weeks. I have a Rikon mini with a CS mandrel. I've so far just been turning slimlines, and I notice that on most turnings, when I turn the outboard blank I get chatter and howling. Am I doing something wrong? The inboard half is always smooth as silk. Is my mandrel flexing or something? Any help would be appreciated. Thanks.