I stumbled across the HAMB a few years ago when I was building my '37 chevy pickup. That message board caused me to find metalmeet and recently this website.
I just got done building a reciprocating hammer - here is link to that thread:
http://www.metalmeet.com/forum/showthread.php?t=13213
I'm still tweaking the dies, but might just break down and buy a set. In the next few weeks I plan to make some beading and planishing dies for it. So far it works well.
The next thing that i build will be an english wheel and I will document that build on here.
-Drew