Friday, July 28, 2017

KNIFE MAKING: WORKING WITH UNKNOWN STEELS



Let me make it clear that whatever expertise I have regarding knives and knife steel arrives from years of hobby bladesmithing and a lot of self-study.  I rarely, however, sell any of my knives because I’m leery of letting my blades fall into the hands of strangers.  My reclusive lifestyle in the woods fits my personality but it comes after years of, what I believe, was fighting the good fight to preserve nature and the land.  I’ve published hundreds of newspaper and magazine articles and have now written three non-fiction books and one novella.  Nothing has ever come easy and I’ve had my share of bad luck along the way.  In other words, I’ve paid my dues and at this point in my life I’d rather not complicate things.  I’ve written that passions are the rudders that steer men’s lives and in my case my love of nature, simplicity, minimalism and my family have plotted the course of my day to day life.  In my way of thinking a knife plays a role in all of that.  As I’ve mentioned in this blog there are strong parallels between human evolution and the construction of tools.  The knife, whether a rock flake or the product of a CNC machine, lies deeply wedded to our collective unconscious; it bonds our present to our past; it unites us as humans.  In the late afternoon I’ll walk to my little shed attached to one of our small barns and I’ll instantly feel serene.  Surrounded by hammers and files, an anvil, a home-built forge, a small vise, shop-made tongs, an ancient belt sander and drill press, and a new angle grinder purchased after the one I’d owned for years decided it wanted to retire.  Nothing fancy, nothing expensive (unless you count the Kanca anvil I bought last year), and nothing all that modern.  In the shed I’ve got a decent pile of leaf-springs that have been turned into everything from large camp choppers to small puukko styled blades.  The steel is 5160, or so I’ve been told.  I’ve not encountered any problems with my leaf-spring steel so I’m content.  I’ve made hook and crooked knives out of old files (W1 or W2?) and I’ve also made knives from store-bought steel ordered from a Texas distributor and an Oklahoma distributor.

If you want to know something about knife steel then I suggest you go to technical websites or visit a library and read all you can on metallurgy.  These resources should be of professional quality; in other words, they should be filled with empirically obtained data based on bona fide research and sound engineering information.  There will be some mathematics involved with loads of graphs and a fair amount of chemistry as well.  If this sort of stuff isn’t your bag then I suggest you learn to work with one specific type of steel (1080, 1075 for example) and be done with it.  I know people out there who hate science and would rather be tortured by a terrorist than have to delve into anything mathematical or relating to chemistry or physics.  And yet, they want to make knives.  They might be good craftsmen or women but they will never completely understand what they are doing nor will they be well-versed in the technical sides of steel.  I even know someone who bought two forges (gas and charcoal) then bought a 200 pound anvil and only then did he try to forge a knife.  Mind you, he’d never forged anything in his life.  He tried to make one knife from a railroad spike and realized it was not a simple thing to accomplish and to my knowledge has never used his anvil or either of his forges since then.  This of course makes no sense because the prudent thing to do would be to ease into the hobby slowly.  My first knives made years ago were crude by all standards.  It was before the World Wide Web and as such my research into the field was limited to what I could find at the library assuming I could find anything at all.  True, I grew up next to a blacksmith shop but never received any instruction from the busy blacksmith working there.  My buddy and I used to watch the man using the forge and pounding red-hot steel on his anvil.  We used to cover our ears when he’d turn the damn power hammer on—my mom hated that noise and so did I and my sister.  Our house, by the way, was only about 40 feet from the shop.  Anyway, despite too many years in academia all I really learned in the following decades was brought to me via my own curiosity and insatiable desire to learn.  I’m a self-learner never having cared much for pontificating and oftentimes pedantic teachers and professors.  Besides, long hours of sitting in rows are bad for your back and after a while the teacher/professor turns into something akin to a noisy cicada.

So it was that the chemistry and physics of steel came from a lot of reading, and the experience of making knives came from a lot of doing.  Mind you, one place I seldom visit is a knife forum.  There are tons of knife forums but they tend to give me hives or at least raise my blood pressure.  While you might get some good information on a forum you are just as likely to receive crapola.  Seriously, knife forums are jammed packed with misinformation.  A common thread on knife forums is the use of “unknown steels.”  That’s a very touchy subject that is neither black nor white.  Let it suffice to say that whatever you are told on a knife forum should be checked and then double-checked.  Don’t ever take anybody’s word for anything until you’ve verified the information through detailed research.  Here’s one example that centers on using used lawnmower blades for knives.  Now for whatever reason there are people in the world who will automatically conclude that any chunk of steel can be used to make a knife.  Perhaps that’s why you’ll see “knife looking objects” made out of rebar and railroad spikes.  And perhaps that’s why you’ve got people out there—on forums and even on YouTube—saying they’ve made great knives out of lawnmower blades.  Now I don’t know these folks and doubt I’ll ever get a chance to meet them.  But my advice to you is don’t believe everything you see, hear or read on a forum or on YouTube until you try it for yourself to verify its validity.  Test the material first.  Make sure there isn’t any quicksand along the way.

Over the last few months a couple of friends have given me dozens of riding lawnmower blades.  Some of these mower blades are brand new having been used on one particular  riding mower that decided it didn’t want that career anymore and so the owner had to get rid of it and buy a new one.  The new mower uses a different blade size.

It wasn’t until a few nights ago that I finally got a chance to check out the mower blades.  The steel looks interesting and there’s always the expectation that I’ll have obtained a free source of knife steel.  Keep in mind that knife forums and YouTube are maggoty with people saying they made fantastic knives with lawnmower blades.  But how can I really know one way or another?  Forums are notorious for people repeating old wives tales.  One such tale says that lawnmower blades are made of 1080 steel.  The way these forum chismes (gossip) form is that one guy will pull that information out of who knows where and then another guy will say, “Well I heard that…” and then another guy will repeat it and then another guy and before you know it one of the legions of self-anointed forum gurus will say, “I’ve got it on good authority that lawnmower blades are made of 1080 steel.”  Every now and then an actual thinker will come along and say, “Wait, that doesn’t make much sense.  If lawnmower blades are made of 1080 then won’t they be too brittle to be used in such a manner?”  Of course, that makes sense.  A mower blade made of 1080 will likely snap into pieces of shrapnel if it hits a stump or large rock.  I can smell law suit.  So it behooves manufactures to make mower blades out of soft, malleable steel that will simply bend and not shatter.  It would be a waste of money to use something like 1080 and then temper it down to nothing so it won’t break apart when it’s a lot less expensive to simply use cheaper, softer steel.  Besides, soft steel wears out faster and forces folks to buy more blades.  Oh my, don’t people understand how modern Capitalism works?  Use cheap labor and cheap materials but keep prices high.  The object of the game is profit.

This discussion applies to all unknown steels from lawnmower blades to mill files to steels you might find at the scrap yard.  Some people will declare that the use of unknown steels is tantamount to heresy; its mindless and when one does a comparative analysis of costs, using unknown steels is in fact more expensive than using store bought known-steels.  To which I say, Bull Scat!  But I’ll shy away from such an argument and simultaneously remind myself why I came to the woods.

But for many knife-making or bladesmithing hobbyists there is a primal desire to experiment with unknown steels, and that’s exactly how our ancient ancestors felt when they wandered onto new territory and found a type or rock heretofore never seen before.
“Hey, look at this rock.  I’ve never seen rocks like this before.”
“Well aren’t you carrying your knapping kit?”
“I sure am, cousin.”
“Well, give that rock a try.  See what kind of spear point it makes….”
And in likeminded spirit the hobbyist just has to experiment.  A cost analysis is measured not how a myopic economist might do it obsessed with “the market” but instead how the inquisitive scientist proceeds.  The economist lives in a little box but the scientist lives in a cloud of wonder and imagination.  So the hobbyist must experiment and to hell with what others might preach.

So I picked up a mower blade and cut it into the shape of two knife blanks.  The first thing I noted was that the steel felt soft to the angle grinder’s touch.  Even so, there were some good Fourth of July sparks shooting out so I remained hopeful.  I fired up the forge and warmed my canola oil-filled ammo can and then set the two knife blanks into the fire.  The steel was about 3/16 inches thick or thereabouts and it didn’t take long to go to critical.  I plunged each red-hot blank into the canola and then onto the table where I allowed the steel to cool.  So far so good so I prepared for the file test.  I chose three files and took one of the blanks and cradled it in my gloved hand and drew the file across the steel (the anticipation mounting) and like a leopard’s claw ripping into soft flesh the file raked a path across the steel.  Quickly, I took the other blank and tried one more time.  The leopard’s claws dug even deeper.  If steel could bleed, then this knife-looking-object was in the midst of committing suicide.  I turned and looked at that luscious pile of lawn mower blades stacked against a wall.  A thought occurred: Maybe I’ll discover a mower blade of better steel?  Then another thought: In a couple of days I’ll quench in water.  I then grabbed a piece of one of my leafsprings and tossed it into the forge along with a piece of 1095.  Waited to critical temp then immersed in the canola then grabbed one of my leopard’s claws and it began skating.  No marks, no scratches, good steel.


So what’s the lesson here?  First, you can hope for the best but you should be prepared to test things first.  Knife making with  unknown steels is not a place for true believers.  You need to be a skeptical scientist instead.  Run the spark test, heat-treat the steel, run a mill file across the result.  Then do it again.  Make a blade and run it through an obstacle course.  So do lawnmower blades work for knife steel?  Some folks claim they do.  Forgive me, however, if I roll my eyes.

Shucks!

UPDATE:
I water quenched several samples of the lawnmower blades I have in my shop and none of them heat treated properly.  As I see it, lawnmower blades are not suitable for knives of any sort. If you were planning to make a knife from a lawnmower blade then may I suggest you verify its potential by first heating a part of the blade to non-magnetic and then quenching it in water. A high carbon steel sample will invariably snap but a sample with inadequate carbon content will remain pliable and most likely bend.  The mantra should be to check first before you proceed. Good luck with your projects.   

3 comments:

  1. Excellent advice,don't listen to Chinese whispers.
    Thanks Arturo.

    ReplyDelete
  2. Is there anything that could be done to increase the carbon content in the steel?

    ReplyDelete