Holding thin wall cylinders for milling

[KSky]

I need to CNC mill a large number of thin wall cylinders. The part looks a lot like a cap from a spray paint can with some internal features. To make it even more fun, I have to be able to flip the part and clean up the opposite side.

Right now I use some custom soft jaws in my vice, but to hold things tight enough it sometimes makes the part out of round since it just clamps two sides.

I was thinking of going with a 6 jaw chuck with some soft jaws so there is a nice even hold all around the part but I am not finding soft jaws for a six jaw chuck. I will try a four jaw if that seems like it will work.

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[Jim Dawson]

Hi neighbor, sort of. I'm in Sandy, Or

Here is how I did a similar job. These are PVC cylinders, very easy to deform so needed to be captured all around. The fixture held the full OD of the part. I used MDF to make the fixture. The fixture halves are screwed into the soft jaws so they pull apart when the vice opens.

[KSky]

I have a similar setup, but my situation is a bit more complicated.

The parts have to be machined on both the inside and outside, and flipped. There are a couple different sizes so that means two soft jaw sets per size. One for raw stock, and the other once it's flipped.

This is what I have now.

[Jim Dawson]

Without seeing the part, I can only make a general suggestion and wild a guess. You might need to revisit your order of operation. I normally try to make a pocket that will fit either the internal or external features for holding the part in a second operation.

There are a number of 6 jaw chucks available with removeable top jaws, it would be pretty easy to make soft jaws for those. Maybe even a 3 jaw chuck with soft jaws would work if the soft jaws capture the full ID or OD of the part when closed (or opened)

[1875]

I'd vote 3-jaw with soft pie jaws. You'll be fine once you get more support around the circumference.

[Bluegillman]

Hi neighbor, sort of. I'm in Sandy, Or

Here is how I did a similar job. These are PVC cylinders, very easy to deform so needed to be captured all around. The fixture held the full OD of the part. I used MDF to make the fixture. The fixture halves are screwed into the soft jaws so they pull apart when the vice opens.

Add plug that won't mess up diameters that what we to too parts have to be .0002 with no egg or run outs