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I Forge Iron

Help with slit/punch

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I have made between 15-20 axes and hammers punching with a striker and a reformed ball peen hammer for the punch and I've never had any trouble. Now I am trying to make top tooling to for power hammer. So far this is my result. The larger piece is made from Hi-Tuff and I realize that I made it too big and I guess I shouldn't be surprised it got stuck, the smaller one is 52100 and I expected that to work. (Actually I expected both to work). Axe material is 4130. What am I doing wrong? Is there a basic technique difference between punching under power, or am I going wrong with the tooling. The tool is stuck pretty good in both pieces.





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Tools look like they may be mushrooming at the end, which is pretty easy to do with a power hammer if tool is too long, gets too hot, or bottom section of stock gets too cold during the punch.  Also bottom edges on the one you show the business end of don't look well configured for cutting of the "plug" from the stock once you flip it over to punch the obverse side.  I suspect you may need to keep your tool colder during the operation (or possibly consider a hot work steel like H-13, reportedly Uri Hoffi uses tungsten from recovered ordinance for his, though I think he uses a hydraulic press), be careful about "bottoming out" and adjust your tool end configuration.  I know some folks use a round crossection punch under the power hammer for their hammer dies, you might want to try that.

What type of power hammer are you using?  I expect there is a great difference in punching eyes between use of a small, fast, self contained hammer (like an Anyang 33) as opposed to a slower, heavy hitter (like a Bradley 300).

You might want to check out how Brent Bailey uses his slot punch under a power hammer in this video (note in particular how he turns the stock 90 between strikes to release the punch, his use of coal dust for lube, and that he doesn't try to punch the eye in a single heat):  


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The tools are clean. I have a grinder and can touch them anytime. I think that I am just not keeping the tool cool enough and it is upsetting just enough to get stuck. I also made my own bee wax linseed oil lubricant. I am using a tire hammer which does hit fast, and I'm realizing there are a few tricks to the technique. I'll play around more with the geometry of the tool too.  I have to get a few axes and hammers ready for a craft show ASAP so I am going to get them done and open the eyes with a striker. I will come back to this soon, however. I also think that there is not enough space between my dies, so I am going to think about making a shorter bottom and try to get some space this way.  Brent Bailey is great. I met him at SBA Murphreysboro last year where he along with a couple of others helped me make a 3 1/2# rounding hammer which was the second or third time I did something like that. 

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