Vibration in Machining Thin Walled Pipe

[cvan]

I took on the challenge of reducing machining chatter on some proprietary threads we are machining into 20-48" OD Pipe , rougly 1-2" wall thickness. In one case a 24" length section is mounted on a vertical turning lathe and in another a 40 foot section is aligned in a horizontal boring mill (interestingly enough it's the surplussed machine that was used to cut the infamous o-ring grooves in the challenger booster rockets!!). The question: is this vibration too complex to try to deal with quantitatively. These threads are machined on a conical surface, who knows how many modes (axial, longitudinal, radial) of frequencies are going on at one time. I am thinking of compressing a 1" sheet of 70A polyeurethane around the affected area w/ a steel band.

 

[cvan]

Moderator: Please withdraw my question, it is obviously not worthy of anyone's attention or explaination. I will work on this subject elsewhere. Thank you.
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[GregPerry]

No experience with this but your idea sounds worth a try.

You could try and spot weld a stiffening ring close to where you are machining. You will have to grind it off afterwards, i dont know if this will be allowed for your application!