Hi Jim, the red mat is a foam pad I was kneeling on, it was not under the mill.
Your observation is 100% correct.
IF I had been working on the side of the mill and not working from the front I would have seen (possible) the position of the wheel which is a swiveling castor.
Or if I had another person there just for a second set of eyes this might have been avoided.
30 years ago I did a lot of heavy rigging and lifting, I have set 60" cast iron gate valves and 12' sluice gates and set the pumps and motors/engines but that was 30 years ago and I have not been around heavy things since.
I have said that the 12" channel should have been longer, I might add a 6" piece of angle iron to lengthen the channel and so that the castor could do a 360° revolution.
The 12" channel is "safe" if I just lift 1/4", with that I have full movement of the mill.
Here is another picture of my bench, luckily the bench took the full force of the fall and saved the mill, no serious damage was done to the mill besides the
broken motor cover and that piece is cast iron so possible I can braze or silver solder it back together.
I can easily repair the bench.