Hola Regarding the cold heading process I have a question and would appreciate an answer a lot. The wire, from which is bolt made, is alloy-steel but the machine is old. I have been seeing many times breakage of needle inside the die and I figured out what was the cause, I even fixed it on my own but now I need some deeper understanding why exactly this thing, which I will mentoin in my next sentence, caused the problem and how come it worked what has been implemented - I didn't believe I will solve the problem in that way. The cause was too small deviation (deviation = ''amount'' of empty air) between wire and tool for cold heading. There was not enough air and the cutted part of wire (knife has nothing to do with my question) probably couldn't move ''freely''. So what I did was just adjustment of this deviation (empty air) between wire and cold heading tool. Now the needle doesn't break anymore. However I would need some deeper understanding why was this cause, why needle in the die has been breaking and how come that this adjustment actually fixed the problem? Hopefully this post could be also suggestion what to do (though this suggestion could be obvious for some people) if anyone else will have the same problem.