I'm relatively new to bowl turning and I had a bowl explode off the chuck today and it scared the crap out of me, along with making me pretty gun shy. The blank was ash, approx 13" in diameter once I got it roughed out. Had the outside finish turned and mounted it on a 3" chuck ( I opted for the 3" over my 5" because of the way I wanted the base to look. I had over 1" of shoulder beyond the recess for the chuck). I was nearly finished on the inside, had the bottom completed along with the sides, from the rim down approx 3". All I had left was an inch or so of thickness to take out in the transition area between the side and the bottom to finish the bowl. I was taking my time making sure the tool rest was moved and placed correctly as I progressed. I made a mental note of how easy the gouge was working and I wasn't forcing anything, was in a good rhythm with the correct overhang off the tool rest. The shavings were flying out nicely. I started another pass with the gouge and the bowl just blew apart. I was out of the line of fire thankfully, because it was ferocious.

A few other things regarding the circumstances. I was turning at 1400 rpm. Was this too fast for that bowl size and chuck size/method? The bowl was seated firmly in the chuck and it was only expanded a few turns from fully closed to fit my recess. I had checked it several times and re-snugged it each time. I noticed no vibration or anything amiss regarding the chucking.

Is there a better order or sequence of turning the side, transition and bottom?

There were 2 cracks on opposite sides of the rim about 1" down each side. I debated about turning the rim down below the cracks to eliminate them but at that point, I had not. I didn't notice any other cracks or defects in the blank, especially down into the bottom of the bowl where I was working.

I'm at a loss for how this occurred. My tool positioning and technique was good and working fine, pass after pass. It sure didn't feel like it was a catch that initiated the failure. But I suppose at that rpm I wouldn't feel the catch before the bowl exploded.

I'd appreciate any advice I could get on this on how it might have occurred. Thanks.
Randy