Bummer... now that you know what is possible to break perhaps you should order 2 of them, one to replace the broken one and one on spare. I have done this when I bought my Dewalt several years back. I have had one upper clamp strip out, luckily I am an ex aircraft mechanic and have the tools to oversize the stripped hole, retap it and put the next size set screw in. It is nice however to know that I have a spare holder should I need it. Take pictures of a clean shop.... I have not seen one in a LONG time hehe
DW