My bucket_mill.py project ( https://github.com/nathanielstenzel/bucket_mill ) seems to do okay with the toolpath. Unfortunately, the chuck on my router warmed up and decided to loosen up its grip on the bit. I did not notice that happened so a little bit later it snapped off and shot at the wall. I am lucky it did not fly at me. The bit cost $8-15. I forget the exact price. I imagine the bit would not have heated up as much if my chip size was bigger. Maybe I should have tightened it down even tighter too. I thought it was plenty tight.
I’ve had bits just pull out because I was loading them heavily and the collet simply couldn’t hold them in against the downwards thrust.
I think that the router speed was fast enough that it should not have been a problem in this particular case. I have seen that problem other times though.
@John_Bump , when it comes to chip size, does chip depth count? That is kind of independent of feed rate. I just made an adjustment to my code so that I can cut deeper each rough cut pass. I have heard plenty of times that bigger chips cool down the bit.
And yes, I just made another improvement to my project.
I just added a cut-depth parameter for rough cuts.
Bigger chips imply less rubbing, for sure. But for me they also mean more force and specifically more pulling to yank the bit out.
@John_Bump just how tight can we make the chuck? Will it cause trouble if it is too tight?
Why the bleep don’t they make the bits with a ring around it that would stick in a groove in the chuck to ensure it can’t slip out? Seriously!
I have some bits using weldon shanks that have a big flat ground in them that a setscrew buts against. That prevents them coming all the way out, but they still run down sometimes. With that said, most of my problems went away when I started getting bits that had shanks the length of the entire collet and clamping them pretty firmly.