Hey, CP brain trust.
I have to expand a 5mm existing hole to an 8mm diameter hole in a metal disk, in order to glue-in a threaded insert into it. Top of the insert is 11mm. The disk is 100m in diameter; it is heavy and magnetic; feels like steel with metallic paint on it.
It is very important that the hole remains 100% centered and vertical. I can't come up with an idea for how to secure both the drill and the disk in place co-axially for drilling without running the risk of either one of them kicking and ruining the disk.
I have drills/bits and vise grips in my garage. Also have a wood-turning lathe, but unsure if it's of any use in this case.
Any meaningful suggestions from guys familiar with machining would be very much appreciated.
