What happened?

[skeeterman]

here is an mpc of a stake cutout i had help from oustanding members on here. i cut this out today, i use a sled that holds the board in center of sled, used this sled multiple times so sled is not issue. the cutout was max depth of .300, so it would take three cuts to cutout.
everything was fine while making first two cuts, then i heard an awful racket , ran back in to find that the third cut i had seen sparks flying and then the bit had broke. stopped machine and pulled sled out the part was already cut out of the sled and the 3rd cut had just started and was cutting into the round bar between rollers that the guide slides on, .
what could have caused this and check out my mpc to see if that was the problem. the sled is .75 thicknes and the wood in sled was .75, i have used this many times , this is a first for me
thanks Steve

[RogerB]

Your bit came loose .What chuck do you have.

[badbert]

I usually use more tabs. But other than that... If the bit plunged that deep, maybe the z encoder is dirty?

[skeeterman]

i have the rock but i tried pulling on what was left of bit before taking out and i couldnt move it , but it would be tough to move with fingers with even the slightest amount of squeeze with the collet.
so you could be right. thanks
we posted same time badbert, i will check encoder

[hess]

loosen the bit on the rock now with the t tool still in the nut pop the t tool with the butt of you hans a few times. I have one rock that the colar will hang and not give way making it hard to draw out a bit use a needle nose on the bit or adator. if that fails just remove the lower hafe of the spindle and clear it out once off the unit