File knife Question

[Moose_Meat]

Is there a secret to making a file knife strong & unbreakable?

At the gun show this weekend one of the guys had knifes made out of old files. He claimed they were unbreakable, I asked him what he did to make them unbreakable. He said "Nothing, files are unbreakable by nature" this I know is not true, I've had files break just from being dropped.

I have worked in the metal trade for over 30 years, use a file daily.

 

[ameling]

Sounds like a lot of "hot air" advertising hype to me.

The only way to make a file "unbreakable" is to anneal it. Ditto a knife blade. But that also means that it will dull fairly fast. (And we all know that even an annealed file/knife can be broken if you work at it right.)

Doing that "thermal cycling" just before the final heat-treat quench does a lot to cut down on breakage, but only some of the new modern specialty "wonder alloys" can approach that "unbreakable" claim.

Yup, seems like "advertising hype" for people who don't have a clue about knife and file blades.

Just my humble thoughts to share.

Mikey - yee ol' grumpy German blacksmith out in the Hinterlands

 

[RickD]

Never heard that claim about file knives before..

 

[ladysmithtrading]

MM, hope you had boots on when you were talking to him and listening as the BS was gettn shoveled pretty deep from him!!!!!!!!!!!!!!

 

[LRB]

There are a number of steels that can be very impressive with a good differential temper, and file steel is one of them. However, if you take a good blade too near it's side load limit, repeatedly, often enough, something will sooner, or later, give. Heat treating a knife blade is a balancing act between getting a blade that will have some give to it, but yet have an edge hard enough, and tough enough, to do it's intended job. One could spring temper the entire blade, and for all practical purpose, have an unbreakable blade, but it is not going to hold an edge very well. Too many smiths put too much emphasis on how well, and how far a blade will flex, rather than how well it cuts, and holds an edge, which is the original purpose of a knife. A knife is a cutting tool, and not a pry bar, and should never be used as such. Most all tools have a primary purpose, and intended use, much the same as Mr. Amelings fine fire strikers. They are heat treated to produce a maximum spark. That is their intent. Drop one one a hard surface, and it could easily break, but it was never intended to with stand that kind of treatment, it's purpose is to make good sparks. Flintlock frizzens are often of the same steel as Mikes strikers, but require a temper in order to with stand the punishment of being repeatedly hammered with much more force than a striker gets, or could handle, without breaking, but the frizzens ability to spark well without this greater force is significantly reduced. Always, beware of outlandish claims made by some knifemakers. Your first instincts are most often correct.

 

[paulvallandigham]

Amen, Wick. :thumbsup:

 

[ameling]

Amen again.

Too many people have hugely exagerated expectations of their knives, axes, and other tools. I know people that DEMAND that the knife or axe/hatchet they buy be "razor sharp", and hold that edge through lots of hard use for a year from next Tuesday before the edge needs a "minor" touch up". And be able to also use that axe/knife as a hammer, pry bar, and hotdog roaster without damaging it. An axe or a knife is a cutting tool - it's that simple. If you use it, it will need to be re-sharpened after that use. If you "abuse" it by doing other things with it, it might break. If you want anything more than that, just go shopping in Blade magazine for one of those modern ... wonder tools ... they hype in there all the time.

That's also why I don't make knife/striker combo tools. The striker portion needs to be almost as hard as you can get it. But the knife blade needs to be much softer so that it doesn't break by sneezing on it. And the transition point between the two different heat-treats is where all the stresses meet, and where it will eventually break.

Same thing with the other "combo tool" type flint strikes - the coffin shaped Chispa and the teardrop shaped Voyageur. Some (and I mean JUST some) of the originals had the end ground to be used as a screwdriver. But to be a good striker, the metal will be WAAAAY TOO HARD to be used as a screwdriver - if you want to put any pressure on it. That end will crack/break. Ditto that hole in the coffin shaped Chispa being used as a ramrod puller. It will usually work, and the wood ramrod will often break before you put enough pressure on it to break the striker. But that striker may also just break first.

SO the main point is, get a tool dedicated to the task at hand. "Combo" tools all compromise the qualities of each tool included. And if one part breaks, it often ends the use of the other parts as well. So you are better off getting the separate tools in the first place.

Some of these new "miracle" metal alloys have warped the expectations of people about the properties of a traditional knife. Adjust your attitude and expectations to the KNOWN qualities of a traditional knife. And let any maker/seller know about the HYPE he's spewing out in his "advertising".

Just my humble thoughts to add to the discussion, and best used in conjunction with your own research. Take them as such.

Mikey - yee ol' grumpy German blacksmith out in the Hinterlands

p.s. Hmmm ... I wonder what "claims" these hucksters would use to sell a true Wrought Iron knife? But once you have used one, it will truly surpise you. Ditto an all wrought iron axe/haw - without any steel cutting bit. Those old wives tails about wrought iron just don't hold up in actual use. Just ask Gerry Barker about his work with wrought iron years ago. He even had an all wrought iron cut-off hardy for his anvil!

 

[wildeagle]

Good info and warnings guys. And remember even EXCALIBER broke, at least in one of the stories :shocked2: