I was building a very simple form for some concreat that will be the base for a lamp post in my Son's front yard. Went out to the back shed and found some material to make the box. Basicaly it was 15x15x15 . I had to add a couple pieces of 1x2" to join the pieces to gather. I was running all sections past my rip fence to give a nice edge to screed the cement off the top edge. I looked up for a split second on the third piece ( there were four. Had only about 1" left to cut when all of a sudden the piece was spun out of my grasp and smashed into my thumb. No cutts or blood but I am finding out to day how important the thumb on my right hand is. I was just very very lucky that it was only a sprain. I have been doing this type of work for more years than I care to think about. All the more reason to pay attention and not to take things for granet. I will have that in my mind from now on when operating all of my equiptment. Hope you all will pay better attention than I did.