quench test on farriers file

[Scott Roush]

I'm just getting around to playing with my files. I have a Save Edge (made in USA) farrier's file of unknown age. I brought it up to non magnetic in my woodstove using a hand bellows then water quenched the tip.  It snapped almost immediately in a vise. The steel has a very nice smooth appearance.  I'm not sure how well this pictures shows it.  Looking good?

 

Another general question..... I'm reading Goddard's 'Wonders of Knife Making' book and he has a section on decarburizing.  Will this be an issue making stock removal knives doing all my heat treating in an electric kiln?  Will I need to be making grinding allowances for removal of decarberized steel on the edge?

And one more!  I'm having a hell of a time making nice 'tang slots' in my 1/8" brass sheets for making simple flat gaurds or top plates.  The problem right now is that the knives I'm making are very thin and it's hard to get any kind of tool in there to cut or smooth out.  What do most people do for this???

Happy New Year!

[Lin Rhea]

Usually the decarb will be removed as you finsih the blade. It's a very thin layer of the outside skin of the blade.

While here I would point out that any problem with the hardness, or softness in this case, would be caught by doing simple tests along the way. When I harden a blade I test it with a file to see how it acts. If it feels a little soft and easy for the file to cut, I may file a little deeper to make sure I get through any possible decarberization. Usually if I detect decarb, I file a little and I find hard steel.

I also test in the same way after I draw the blade back. I know that it will be a little softer and act a little different. Have a testing file that is handy and use it for only that. A dull file will not be accurate.

Even after all of this, BEFORE I proceed with the handle, I put a cutting edge on the bare blade and chop test to look for chipping. If I dont get chipping, I can further test with a brass rod. In fact the brass rod should be part of your testing.  If I'm satisfied that it's hard enough, but not too hard, I finish out the blade.  

Maybe Karl will start a thread to show testing with a brass rod.     Lin

[kbaknife]

I might, Lin. Let me get my batteries charged.

Scott, one thing you may not be thinking of here on that file is that it's already hard in the first place! Why are you bringing it up to a high heat and quenching it? It's already hard.
That's like putting ice cubes in the freezer to "freeze" them.
There would be no reason to put the ice cubes in the freezer to freeze them until they melted first.
Like your file, there would be no reason to go through a hardening process until you SOFTENED the steel FIRST!
And the only reason to soften the steel would be so that you could drill or file/grind away material.
I can't help but be curious as to what you were trying to accomplish by your experiment.
It's nice to know that you are able to achieve a high enough heat in a wood stove to attain 1400+ degrees, but I do question the consistent temp and ability to hold it.
I think I would suggest putting resources and time into building a rather inexpensive propane forge first so that your "experiments" could be done by eliminating some really important variables.
If you want reliable results from your time/resource investment, controllable temps should be the first thing on your list.
Of course, then again, looks like you're having some fun and that's a good source of learning right there.

[Lin Rhea]

Also, you were able to achieve the hardness and fine grain to make a good knife. If that had been a case hardened file, I believe the grain would not be so fine. It's all about testing and trying. Good job.

BTW I use needle files when I have to make the slots thin. Drill a series of holes and take out the webbing to get the slot. Taking care when punching and drilling will save you some frustration. Lin

[Scott Roush]

I did the test because I've heard from various sources that this is a way to test unknown steel.  Several folks who've made farrier file knives have done a similar thing.  In fact, I just read it in Goddards book.  He say's to heat only the tip of the file in question to non-magnetic, quench in water and put it in the vise and bend it. If it doesn't snap like glass... then it was probably case hardened. And then look at the grain.. he say's it should be silky smooth. Am I misreading this somehow?  Lin made reference to this in his post as well.

BTW... I was only using my woodfire for this quick quench test. I plan to use a kiln that can hold up to 1600 degrees with no problem for the actual work on the file.  However.... I am looking into building a small gas forge as soon as I have the time.

Thanks Lin... I guess I need to get some smaller files!

[kbaknife]

Sounds like you did good, then.
Keep in mind that the grain would ALREADY have been reduced as much as necessary for the creation of the knife at the "file factory".
What your test shows is that you did not OVERHEAT the steel and make it GROW! Which is a good thing.
But at the same time, it would be difficult to get a wood stove hot enough to overheat steel.

[Scott Roush]

Thanks again guys.... Looking forward to getting started. It will be a Scandinavian style skinner.