HT a knife from a file

Hengelo_77

Hengelo_77

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Mar 2, 2006
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I've made a knife out of a file

Can somebody advice me on a decent HT?

I assume heat to cherry red and quence.
But tempering?

Foto-OIC3FFMW.jpg
 
It looks good so far not knowing what you have for equipment makes it hard. You are better off using a magnet then by eye. Heat to non magnetic and after it gets to non magnetic heat for a few seconds more and quench in oil it would be best to have proper heat treating oil but if you have none use mineral oil or canola oil heated to around 110f.
Then wipe down and into a preheated oven at 400f for two hours. Good luck and have fun.

Bob
 
I've done one from a nicholson file and it seems to have come out well. I built a small forge from a piece of 120mm mortar tube (lined with inswool and satanite from Ellis) and used Bernzomatic torch fed into the side to heat it up.

Heated the file blade to non-magnetic, held it there for a short bit (probably around 30 seconds or so) then quenced in vegetable oil. I had pre-warmed the oil by dropping in a piece of scrap steel I had heated up as the blade was getting hot. Tempered it in a 400degree oven for two cycles of 1 hour, allowing it to cool until I could touch it inbetween.

It holds an edge very well. I will warn you though, knives from file will rust if you look at them wrong. Keep it lightly oiled and it'll last you a lifetime.

Charlie
 
Your quench temp needs to be about two shades redder than non-magnetic. Your temper should be 425° minimum. I would suggest 450°, and use an oven thermometer. I would suggest canola oil at 130° for your quenching.
 
When you are heating the blade up, try to be in subdued light and check often for magnetic or not about when it starts to go non-magnetic and a little hotter you will start seeing a black line moving asross the steel from the thinner areas to the thicker areas usually, this is decalescence, when the black line has moved across the whole blade it is hot enough to quench. I would guess the steel to be a water hardening steel like 1095 so your best option would be a fast oil like parks 50 or Houghto Quench K.

Barring proper quench oil, You might read this thread, post # 28 in particular and use your own judgement as to whether you want to use that method or not.

http://www.bladeforums.com/forums/showthread.php?t=700542
 
I would still suggest canola at 130°. If you feel lucky, really lucky, try the brine. If you want to be sure of not losing your blade go canola, or even mineral oil, but heat it to 130°. that makes it quench faster. As stated, Parks #50 would be the best, but it ain't cheap.
 
I'm just posting to second what Mr. Ellerby says, he's pretty dang good at this sort of stuff. :) Brine quenching is exciting and even when you do everything right you can still hear the dreaded "tink" at times. File test the blade after quenching, if it doesn't skate a file then anneal and go a little hotter on the next heat treat.

Have you contacted the file manufacturer to find out what steel it actually is? That would really help you a lot.
 
It was an old, slightly rusted file. 'Heller nucut' or something like that was on there. (hard to read)

I don't have any equiptment yet, I plan on building an improvised oven from fire bricks and a propane burner.
I think I'll try a vegetable oil first since it is easier available to me.
The oil used to deep fry French fries etc, would that be a good oil?
 
I will. Thnx for the advice.

Just so I get the picture complete.
What is the purpose of heating up the oil first?
 
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