Railroad Spike Knives and laminating for a harder edge

Okay, I know railroad spike knives are a pretty controversial topic among blacksmiths.  Tempers flare and arguments ensue whenever folks ask if a railroad spike is proper steel to hold a cutting edge.  What it comes down to is that the steel in the spikes don't have the right carbon content to allow them to hold a decent edge when forged into a knife.  Made to flex and not crack under strain, spikes do their job of holding down track admirably.  In order to be flexible, they are made of a medium carbon steel.  Many out there claim that there are high carbon spikes, marked with an HC on the head.  In fact, the spike I use in this tutorial is one of them.  Many believe that they are not suitable as knives.  Fortunately, through forge welding, we can laminate a higher carbon steel into the spike, creating a blade that has the tough medium carbon steel on the flats and an edge of high carbon steel that will stay sharp.  We can now indulge our cravings of making knives out of railroad spikes.

Here is the railroad spike I selected with the high carbon inset.  This insert is a portion of worn out file with the teeth ground off.  I performed this grinding to make sure the surface was clean and free of rust or grease.  This will help facilitate the welding.  I also ground it to the width of the spike, including the taper.  This will help create a nice neat weld.  Any portion of the high carbon insert that is exposed has a higher chance of burning up when reaching the welding temp for the spike, so the insert should be protected by the medium carbon steel that has a higher burning point

It is also important to grind the end of the insert that will we within the spike to a wedge.  This will allow the spike to conform to the insert's shape easier without leaving a gap at the bottom of the split.  The taper of the wedge should be gradual, this allows the spike to hug the insert without spitting it out when hammering the split closed.  Speaking of the split, I cut down the length of the spike, far enough to accommodate the insert.  It is oriented so that the edges of the insert will become the cutting edge and the spine of the blade.  All of this prep work is very important.  Taking care of these details now makes the welding process, which is already tricky, a little less stressful.

Into the fire goes the spike.  The end with the split must be hot enough to open the split up to accept the insert.  I use charcoal in my forge, which is a pretty clean fuel.  Welding can be impeded by impurities that burn off from dirty coal or non-ferrous metals.  Clinkers, which form when the impurities of the coal melt, off gas substances that get in the way of welding and they also cover the air flow.  This keeps the fire from getting hot enough to reach the welding temp.  Charcoal doesn't form clinkers, so I don't have to worry about this.

The split has been opened and fluxed.  Notice how portions of the steel look wet.  This is the melted flux, which in this case is borax.  Some of the borax that contacted steel to cool to fully melt it clings to spike down by the vise.  The flux will coat the steel and keep rust scale from forming, which would get in the way of the weld.  It will also bind to what little rust is present and pull it out when the weld is hammered closed.

After heating the spike once more, the insert is placed in the split and the split is hammered closed.  Heat the whole thing once more and flux it well.  At this point the spike is ready for the weld.  Slowly heat the spike so that the welding temperature soaks into the core of the spike.  I place the spike with the edge of the insert facing down so the heat can flow up through the split.  I rotate the spike 180 degrees periodically so that it heats evenly.  You will know when you have reached the welding temp when the flux begins to sizzle and the portion of the spike to be welded is glowing bright yellow/white.  Do not heat the spike to the point of sparking.  Sparking is a sign that the carbon in the steel is burning off, defeating the purpose of adding high carbon material.  The welding temp is just below this point of sparking, so check the spike frequently enough to avoid over heating.

When at welding heat, remove the spike quickly from the fire and hammer the area to be welded, sticking the split together with the insert sandwiched in between.  I did three rounds of this to assure the weld stuck down the entire length of the split.  To the right is a picture of the edge after the final weld.  Notice there are no gaps along the edge, just a solid piece of steel.  Many times, a black line will be visible where a weld didn't take.  This line becomes very obvious when that edge is ground shiny.  Below is a picture of the tip of the knife along it's back edge.  Ground down past the black crust of oxidation to the shiny steel, you see that there are no black lines.

  If there are black lines you can attempt to flux and weld the spot again.  It is definitely easier to do it right the first time, however.  Another place you would see black lines, if the weld did not take, is along the flat of the blade.  When you grind the bevel, this exposes the junction between spike and insert.  In the picture below, you can see that the flat has no black lines, meaning the weld took.  Do not be hard on yourself if you end up with spots where the weld does not take, it takes

 a lot of practice to get the heat just right and the coordination to quickly close the weld before the steel cools to much.  The knife, which was once a railroad spike, now has an edge of high carbon steel, that will hold a sharp edge.  By hammering the blade evenly on both sides, the high carbon insert stays centered so that it becomes the cutting edge.  After shaping and grinding, I quenched the knife in oil and tempered it to a light yellow.  Sharpened to a razor edge, the knife now awaits a leather wrap for the grip and it's first task as an edged tool.

Charred Bones: Charcoal Making for Blacksmithing

At the Silvaticus Blades smithy, we use charcoal as our fuel for forging our knives and various other implements.  Burning hot and clean, it is a wonderful forging fuel, though not as long lived as coal.  However, having access to space and plentiful wood, making our charcoal is practical for us and thus using charcoal for our bladesmithing is our best option.

Charcoal, in this case, is wood burned in the absence of oxygen, leaving behind the carbon.  All impurities and moisture is burned off during the manufacture of the charcoal, leaving a clean and almost smokeless fuel.  Both softwoods and hardwoods may be used, and each variety of tree provides it's own special qualities to the charcoal.  Pine, for instance, burns very hot but very quickly.  More than likely, you will be using whatever wood you have available in your area.  I use oak because it is plentiful and burns long and hot.

I use an indirect method to produce my charcoal.  This means the wood to be turned to charcoal is placed in a sealed metal container (with a smoke vent) and is heated externally by a fire.  Oxygen can not enter the container so all of it's contents become charcoal.  Another way is the direct method, where your wood is stacked in a retort and allowed to smolder within, having the oxygen controlled by vents.  Eventually the retort is closed up and the fire allowed to die out.  Both methods consume wood to create the heat needed.  In the direct method, a portion of the wood within burns away, leaving behind ash.  In the indirect method, the wood outside the container, in the fire, is consumed. 

I prefer the indirect method because the wood I use for the fire can be trash wood, unsuitable for charcoal.  Brush, half rotten wood, stumps, whatever you have that will burn will work.  The direct method uses charcoal grade wood to produce the heat, thus wasting a high quality material when waste wood could be used.  Also, the indirect method is much less finicky, the sealed container regulates the oxygen, making the method pretty hands off as far as tending the fire goes.

Above is my metal container for holding the wood.  It is a 30 gallon trash can with holes poked in the lid to vent smoke.  As the wood turns to charcoal, it off gases impurities and steam in the form of smoke, creating pressure within the container.  You must have vent holes to relieve this pressure.  I wire the lid in place to make sure it does not fall off during the burn, which would introduce oxygen and burn up all the wood into ash.  These trash cans are galvanized, so do not stand downwind your first burn.  The metals used to galvanize the steel burn off and are toxic.

Here is the oak that I intend to turn to charcoal.  I try to pack it in as efficiently as possible, to maximize the end product.  I use stuff no bigger than a couple of inches across.

Here is my pit that will contain the fire.  I like using a pit because it reflects the heat back at the container, maximizing your fuel and allowing you to use less of it.  Some people will use a 55 gallon drum as their "pit".

Both ends of the pit have air vents to allow the fire to breathe.

Here, I have the container within the pit.  It is surrounded by fuel wood, which in this case is punky/termite ridden pine.  The fire has been lit.

A view of the fire from the air vent.

Once the fire is really raging, as in the above photo, I cover up the pit with a few pieces of corrugated metal, to reflect the heat down toward the container.

Here is the pit, covered.  As the fire burns, you'll notice smoke issuing from the vent holes in the lid of the metal container.  Eventually this smokes ignites and becomes a jet of flame.  You will know when your charcoal is done when there is no longer any smoke coming from the vent hole.  Allow the container to cool completely before opening.  If you open the container prematurely, the charcoal within will ignite and burn up.

Here is some finished charcoal, ready for the forge.  It will go on to forge knives, axes, and other edged tools.  It is even possible to get the charcoal fire hot enough to forge weld, however it uses quite a bit of fuel.  I love the smell and look of charcoal and it's clean burning qualities that make welding easier and does not impart impurities into my blades.  The ability to produce it here on the property is another plus and is easy when using the indirect method to do so.  I will continue to use charcoal in much of my forging, just like my ancestors in Rome did to forge their weapons and tools of antiquity.

Of the Wood

I sit by an open window, the cool night breeze wafting in, carrying the calls of the barred owls from the cypress swamp.  They hoot, growl, chuckle, and shout into the blackness; sending every possum and rabbit scrambling into the nearest clump of gallberry or bracken.  Pines tower around my house, steeples silhouetted against a starry night sky.  Here, we are silvaticus.  Silvaticus means: of the wood or wild.  It is the ancestor of the word savage.  It is an accurate description of our lifestyle, for we gain sustenance from the pinewood and cypress swamps that surround us. 

Even my forge is tucked away amongst the greenery of oaks, pines, and bays.  I char the bones of these trees to create the fuel for my forge: charcoal.  Their sinuous trunks and reaching limbs become the grips for my knives.  The hides of the beasts that skulk in the shadows contribute to the sheaths of these edged tools that rise from the flames like a phoenix.   The gleaming steel does truly reincarnate, since I begin with rusted scrap left to decay slowly in the woods.  You can hear the ring of my anvil echo through the wood and smell the smoke on the breeze as I coax the dead back to life, a necromancer of steel and iron.

As I sit here, late at night, listening to the crickets and watching the fire flies dance through the darkness, I ponder what tomorrow will bring forth from my forge.  What shapes will emerge from the ashes, which lines will appear as curls of wood leave my planes?  Most importantly, who do I breathe life into these knives for and what tasks in a far away wood will they perform?