The dies are 4" x 7" Andrew. I am going through the literature that Bob sent me now . Any info you could come up with would be great. I will have it set up and running next week so it won't take long for me to figure it out . I do quite a bit of architectural work, tool making and I would like to start making some pattern welded knives etc. I also make sculpture for which I have big plans for this hammer. I really look forward to the control of this beast . I haven't been up to Decorah in years but if you feel like making the 3.5 hour drive to Fairfield let me know and you can check this hammer out for yourself, with an IPA donation of course!