I have a question about using a 1/2 carbide boring bar. I am boring out an ID on a CNC Lathe using 1/2 boring bar, the boring bar is hanging out 3" . I am only taking .003 per side and I am getting the wrinkle affect on the wall. I have tried it at numerous feeds and speeds and can't get it to work out just right. The last run I was running at 1000rpm with a feed of .004 and the finish came out great, so I put another part in and got a wrinkle finish so I was back to the drawling board all over. The material is 6061-T6. Any suggestions out there?