as i'm retired now, and only have my own machines to play with, i take great care not to do things that would cause damage to them.
I bought my Bridgeport clone mill brand new and vowed to never to put a "divot" in the table, even covered the table on both sides of the vise to prevent dinging it. Predictably, one time I forgot to lock the quill before milling a slot in a piece clamped to the table with the power feed engaged and the spiral end mill broke through the part and milled a slot in the virgin table
AAARGH. I guess it was inevitable.
