I need to modify one of my attys a bit and its made from 304 SS. It has an airflow ring that was made too big and it is unusable at the moment but if I were able to shave off about 1 mm it should be able to work. However, Im running out of ideas on how to go about it as I've taken it to a few jewelers and vape shops and nobody is able to do it. I tried sanding it but after like 1 hour of sanding im pretty sure that I might of taken off like .00000000001 of metal off it. Any help would be much appreciated, thanks.