October 23, 201411 yr Forged a nail header, from a crow bar. I make it orange/non magnetic and quenched in engine oil. It was so hard,I cant get a file to bite. Is that too hard? Will it crack in use? If so.....Should I heat it to blue or simply heat to orange again and air cool? I have a commercial nail header bought from On Center tool and it works soooooo sweet. I can get my file to bite into it. So it made me wonder; how hard it too hard for a tool of this caliber?
October 23, 201411 yr Try annealing the header. Heat to an orange heat, hold for a while, then bury it in ashes or sand or vermiculite and let cool overnight. See if it works any better. Nail headers do not have to be super hard. They are cold steel holding red hot steel. Try it. See what happens.
October 23, 201411 yr crowbar is often a medium carbon steel. You mentioned hardening it but no mention of drawing a temper on it. This is a bad thing. After hardening you should draw temper on most alloys the temperature you need to draw to is dependent on the alloy, intended use and personal preferences. Luckily you can work your way up to the temperature you want. eg draw at 400 degF, check with file if too hard draw at 450 degF, test and so on. (you can start at lower temps and go up by 25 degF increments if you like...)My nail headers get used by students and are forged from automotive coil springs and I just normalize them; been in use for several years so far.
October 23, 201411 yr Nail headers should be slightly rockered (crowned) on top. With lots of use, I have had a couple of mine get "wallered out" around the holes, the opposite of what should be. I sanded them down, then hardened and tempered again. "Wallered out" is Southern. "Dished out" in Northern. I've heard three good ol' boy sayings about the result of quenched-to-harden high carbon steel. It is file hard; a file won't cut it. It is dead hard; can't get any harder. It is glass hard; will crack or shatter like glass if subject to enough shock. That's why we temper, to take the snap out of the material and impart toughness. The brittleness is thereby removed.
October 24, 201411 yr "Wallered out" is Southern. "Dished out" in Northern. Good that you pointed that out for our northern friends. :D
October 24, 201411 yr Author I heated it to orange and then air cooled. It is a bit tougher now as the file will cut into it. Thanks!
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