How I almost set fire to my garage...

[cncJim]

So I was making a nice little decorative wooden doo-dad for my brother's birthday at the start of the year. Computer told me it would take 90 minutes so I decided to step out and check back every 10 minutes or so......hmmmm....not one of my best ideas!

The next time I go to the garage I am met by thick smoke which started to burn my eyes! Over to the machine I run fumbling for the estop.

Once the smoke cleared (35 minutes!) I took a look at what had happened.

Turns out the z axis coupling had come loose and the whole spindle had dropped into the work piece. The v bit I was using cut through the 15mm oak workpiece, a 10mm bit of sacrificial pine and the 25mm mdf bed But the thing that surprised me was that the spindle collet nut had also managed to "mill" through the above mentioned wood!



I tightened the grub screw on the z axis and tried to move the spindle up - this is where my new found respect for the power of the stepper motors coupled to ballscrews came from - The spindle was stuck fast. As I tried to raise the z the spindle stayed put and the whole machine flexed like a banana! Now I'm the first to admit that my machine is no heavy weight (x - 25mm unsupported | y - 20mm unsupported | z - 20mm unsupported) but I thought the steppers would have stalled before the frame tried to fold in half!

I do feel lucky though, I'm sure I was seconds from a fire starting and I am glad I at least had an estop button, can't imagine how long it would have taken to find the mouse and try and find the estop button in mach!

Thinking back I remember looking at the first cuts it was making thinking it didn't look 100%. I put it down to me not setting my z zero correctly (just started using a probe to set z) and thought I would let it run and investigate it after. Should have seen the signs!!!!

I have now placed a smoke alarm and fire extinguisher in the garage!!!!!