I'm also a little confused. When you state that you "moved the table 180º" does this mean you raised the quill and cranked the Y axis (the in-out, not left right) movement of the machine so that the cutter was now on the opposite side of the workpiece from what we see in your photo?
The best thing to do, especially since the first side of the slotting operation went so well, would have been to simply flip the collet block over the 180º and repeat the operation. If I get it right, your first photo is of the second side before crashing. If that's true and it's a right hand cutter, you definitely had that work "hog in" to the cutter and that's the reason for failure. As long as you had a reasonably firm clamping of the collet, the .007" thick saw would have been in multiple pieces long before it ever moved the piece back in the collet.
BTW, your saw looks a lot bigger than 1-1/8" in diameter. If true, your speed of 150 rpm may be too high for HSS in 304 stainless steel.
The best thing to do, especially since the first side of the slotting operation went so well, would have been to simply flip the collet block over the 180º and repeat the operation. If I get it right, your first photo is of the second side before crashing. If that's true and it's a right hand cutter, you definitely had that work "hog in" to the cutter and that's the reason for failure. As long as you had a reasonably firm clamping of the collet, the .007" thick saw would have been in multiple pieces long before it ever moved the piece back in the collet.
BTW, your saw looks a lot bigger than 1-1/8" in diameter. If true, your speed of 150 rpm may be too high for HSS in 304 stainless steel.