Hello fellow bladesmith,

I've recently started a project of building a treadle hammer. I am conflicted on how to best secure my dies to the anvil and hammer. One thing I've seen online had been a mild steel base welded to a medium or high carbon die, then bolted to the top of the anvil and bottom of hammer. My real question is after preheating and post heating the welding of the mild and high carbon, do I need to heat treat my die to achieve the high hardness necessary in a die? I thought of doing a few thermal cycles with the entire base and die assembled, then heating it to non-magnetic and quenching in oil. Will this quenching destroy my welds? I hope my question came out right. Any advice would be greatly appreciated thank you

Depends a lot on the alloys involved.  If the metal being hit is hot and soft hardness is not a big factor in dies. Abrasion Resistance may play a larger roll; as scale is an abrasive.

I made the dies for my 50lb. Little Giant from 2 1/2" IIRC round shaft and a drop from a drill tool machine shop both 4140. The first time I used 1/4" for the bolt flange like the other guys so we could interchange hammer dies. Unfortunately 1/4" wasn't rigid enough and ended breaking one of the screws. Soooo, I had to drill out the broken screw, it'd stripped so I couldn't easy out it or chase the threads and I ended up drilling and tapping 1/2" fine and replacing the bolt flanges with 1/2" plate. 

I plug welded the center of the dies through the flange and on the perimeters with 7018, pinged and relieved. Heat to non-magnetic, soaked for about 10 minutes and quenched in warm peanut oil from the local deli. Tempered to 400f IIRC in the shop toaster oven till they were a uniform dark straw. The flanges being mild steel were unaffected by the heat treat.  No signs of appreciable wear in about 20 years of hobby use.

Frosty The Lucky.

You have prolly seen how Clay Spencer attaches his dies to the hammer. But if not, Its pretty straight forward. If I remember correctly, he makes a "U" out of 1/4"x1" and welds it to the bottom of the die. This goes thru the die plate on the hammer and is held in place with a tapered wedge. Tap the wedge out, change the die. Heat from welding on the tabs has never been a problem for me.