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Old 02-14-2018, 09:43 AM   #6 (permalink)
More4dan
 
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You might also want to take a look at your bushings and make sure they are not causing the issue. There should be a sharp 90 deg angle between the part that goes into the tube and the transition to larger OD section. If it's rounded a bit, it could "flare" the tube when you tighten up the mandrill. It could also happen if you tighten it too tight or have it too loose that the blank spins on the bushings while cutting. There is no where for the brass to go other than "outward". This is more likely when turning between centers w/o bushings. Which I do often but rarely have this problem. I had to learn to find that sweet spot of not too tight or too loose, but just right.

Also, as others have noted, if the end isn't square then the brass tube won't fit flush against the bushing. The longer part of the brass tube will take all the force and flare outward.

Danny

Last edited by More4dan; 02-14-2018 at 09:46 AM.
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