My company is involved in a magnetic separator drum rebuild.

Why is it so difficult to get a rolled cylinder that is actually round?

the material is 3/16 stainless slightly more than 8 feet long,

and 30.25 ID. We do have some latitude in the exact diameter,but as this drum

rotates around the magnetic element,it must be round to within eighth inch or so.

It should be easy to achieve this,however it is proving to be not so simple.

I  think welding the seam/s and re rolling should eliminate flats from the initial

pinch,am i correct? .I should add that I am not involved in ordering or sourcing this component

from other vendors.

 Is the problem in the way WE specify this "can" ,or is my understanding of plate rolling incorrect?

Is  the ability to "open" the rolls and  slide a cylinder on for another pass common practice?

or is this potentially risky as well.

This item is fairly costly and I am frustated by the lack of quality we are getting.

Any comments are most welcome.

Thanks in advance