Sparky I used to see those on Ebay, years ago, and always thought....what a pain in the ass having to use wrenches/hex keys. Why the guy never used thumbscrews, for the clamping, shows a lack of ingenuity, and apparently, lead to a failure for you.(?)
Which screw(s) failed? the top clamping, or the worm drive that pushes the head off?
A local machine shop can get you back up and running, easily. And, will cost less than the price of new.(although iirc, you may only have paid $69.99 for that one)
I may have to start designing something. π€¨