Quote Originally Posted by JohnHaine View Post
I'm a bit bemused by this. In my experience of breaking cutters the spindle has never stalled, if it had the cutter might not have broken! The last one I broke I made a mistake setting Z height and the machine made a rapid move straight down into the work, fortunately not through the spoil plate. The spindle carried on regardless! Am I missing something?
Cutting 1000 grade thin sheet tend to gum up the cutter. It’s almost pure aluminium. Then it stops cutting and the spindle stalls and the end mill breaks. 6061 alum alloy is better but if the bit gets hot again it can gum up. Mist or flood cooling minimises this risk but it gets messy.