Introduction: Axe Made From Bike Chain and an Old Rasp. Aka: Mad Maxe!
Axes are one of humanities oldest tools and have been in use since before the dawn in civilization up until the present day. There are many variations, but the basic shape and principle has always remained the same. The haft is generally attached to the axe head through an eye in the head.
Axes forged these days have eyes made mainly by drifting; an extremely labour intensive task unless you have access to a power hammer. There is however a second option available. By forging out a billet to shape, folding, forge welding it together and inserting a cutting bit, making an axe becomes a significantly less intensive undertaking. This is an older way of making axes with steel cutting edges, as steel was significantly more valuable in ancient times so this method allowed for making an axe with a high carbon cutting edge, but a more shock absorbent (and cheaper) body of iron.
Forge welding also opens for a whole new world of possibilities in metal working, and in this instructable I hope to show you how to make an axe utilising a broken bike chain for the body and an old rasp for the cutting bit. I have named it the Mad Maxe!
·Anvil or anvil like object
·Axe drift or steel rod roughly 2.5cm (1 inch) in diameter
·Heat source. (My current forge is one of the cheapest gas forges I could get off eBay. I've heard plenty of people say it cannot get to welding temperature, but with a bit of tweaking it gets plenty hot enough. Previously I used a hole in the ground filled with charcoal for forging, but I have never tried forge welding with that setup).
·Quenchant (I use canola oil)
·Angle grinder (with cutting discs and flap discs)
·PPE (Good shoes, eye and ear protection and a respirator i would consider a minimum).
·High carbon steel for cutting edge (I used an old rasp. Old files and rasps are generally safe bets).
·Wood for axe haft
·Flux (I used borax from the supermarket, but anhydrous borax is supposed to be better).
·Chemicals for cleaning chain (I used normal dishwashing liquid, borax and acetone).
(Note that these are just guidelines and what I had available. Work with what you have whether that is less or more than what is on this list).
Step 1: Clean Chain
Generally when I do a new project my first step is planning. I make a sketch, plan accordingly and outline the materials I need. On this project however, you are limited by the materials used to make the axe, so start with a rough idea and fine tune as you go. (On the other hand you may be better than me at planning how the materials at your disposal can be shaped).
An important step either way is cleaning. When forge welding, there are three key elements that are important for a good weld: Heat, pressure and cleanliness of welding surfaces. A chain is going to be covered in oil, grease and potentially rust,and there are many surfaces within the chain that needs to be welded to form a solid billet. I chose to boil the chain in water mixed with dish washing liquid and borax before giving it an overnight soak in acetone. This method seemed to work well for removing any oil from the chain, though I'm sure there are other methods that would be equally as effective. The chain i used had no rust, but soaking in vinegar for an extended period is an effective way of dealing with rust if needed.
Step 2: Turn Chain Into Billet
The next step is turning the chain into a solid billet that will form the body of the axe.
You don't want to leave this step for too long, as rust will form quickly on the chain now that the oil is removed.
First you want to make sure the chain doesn't wobble around while working on it. This would be easily achieved with a welder... Of which I have none, so I folded the chain to what I figured would make a good combination of width and length for a billet (which in my instance was four links wide), and wrapped it tightly in steel wire
Afterwards it's time to forge weld the chain. If using a gas forge you want to run it with a reducing flame, meaning the amount of gas that is injected into the forge is greater than the amount of oxygen (as far as stoichiometric ratios go). This way, all the oxygen available within the forge is consumed and this reduces the oxidation and scale formation on your steel. With a reducing flame, the excess gas will combust as it exits the forge.
First you want to bring your billet to a red heat in the forge. Take it out and give it a good dousing with borax, which will partially melt and stick to the hot steel. The borax will help prevent oxidising of the surfaces and acts as a cleaning agent during the forge welding process.
Return the chain to the forge and bring it to a bright yellow heat. Bring the chain to your anvil and hit it firmly and precisely to set your first weld, but do not hit it full force. Firm and precise blows are key. You will not have a large window of opportunity to set the weld, but don't stress. When the temperature of the billet drops somewhat, reapply flux and return to the forge. Keep repeating the process until the entire chain is forge welded into one solid piece.
Step 3: Preform Chain Billet
Next you want to shape your chain billet into something more reminiscent of an axe (though it will be more of an axe that has been split in half from the edge towards the back and folded out). Flatten and flare out the ends, and try to make each side be a mirror image of the other. A straight peen hammer will help with this, but if you do not have one, you can use the edge of your hammer, or the edge of your anvil to draw the steel out with. As i often like to repeat myself: work with what you've got.
By controlling the angle at which the force from the hammer strikes your billet, you will also be able to control the direction it flares out in as indicated by the red arrows being the direction the force is applied and the blue arrow the consequent direction the steel is drawn out in.
Also, do not forget to clean off scale with a wire brush as you go. This will give the forge welding process later on better chance of succeeding.
Step 4: Prepare Cutting Bit
The rasp i chose to use for the cutting bit was a half round rasp, so the first step was flattening it somewhat. Afterwards the next step was to form one of the long sides into a wedge. The bit will be inserted into the axe body wedge first, while the thickest part of the bit forms the cutting edge. When shaping the wedge, the bit will inevitably curl in the opposite direction of what you want it to (as indicated by the blue arrows and quarter circle), so you will have to correct it as you go. Either that, or you can anticipate what the steel will do and pre-shape it so it ends up the correct shape when you're finished forging the wedge.
Afterwards, grind off the scale and cut the bit to the length you want it.
Step 5: Fold Billet
Next fold the billet in half and around a steel rod to give room for a haft later on.
Step 6: Forge Weld
Now to forge weld the body and then the cutting edge to the body. Same procedure as welding the chain. Get to red hot, apply flux, bring it to a bright yellow heat and weld the body with firm and precise blows, taking care not to weld the very front of the body where the bit is inserted and the eye.
When the body is welded, apply flux to the front part of the axe, insert the cutting bit and hammer the body to clamp it to the bit. Bring both up to bright yellow heat and set the weld as previously. Reapply flux and continue welding as needed.
Step 7: Refine Axe Shape With Abrasives
Now it's time to finalise the shape of the axe. Draw the outline of the axe on the axe blank and remove the steel you don't need with abrasives. Angle grinder (I will always advocate for 40 grit flap discs. They are fast, cheap and effective), coarse files, belt grinder or what have you. I generally start out with an angle grinder and refine the shape with files. Only file on the push stroke unless you draw file.
I will then use the slack part of the belt grinder to shape a convex cutting edge. Leave roughly a millimeter of steel on the cutting edge to prevent warping when heat treating.
Step 8: Heat Treat
Heat treating consists of three steps. Normalising, hardening and tempering. Normalising refines the grain structure of the steel and relieves stresses caused by the forging process.
To normalise, heat the axe up to the point where a magnet no longer sticks to the steel and let it cool down to black heat. I like to repeat the process two more times.
To harden, heat the axe up to non-magnetic and take it one shade brighter before plunging it into your quenchant. I use preheated canola oil for this. If the hardening was successful a file should skate off the edge of your axe.
Tempering will draw the hardness of your edge back somewhat, but in return it will be much tougher. If you use your kitchen oven like me, get an oven thermometer to monitor the temperature. If you're using known steel for your edge, follow the guidelines for that steel, if you're using a mystery steel, a good temperature to attempt tempering is around 200 degrees Celsius or 400 degrees Fahrenheit. I did two one hour tempering cycles.
Step 9: Clean Up Axe, Refine and Blend Colours (last Part Optional)
After the heat treating, your axe is inevitably going to be covered in scale and polymerised oil, so it's time to clean it up a bit. Use a wire wheel to quickly remove lose scale and oil. Afterwards you can give it a vinegar bath to remove more scale and at the same time etch the blade to bring out the different steels and details in your axe. Other etching fluids can ofcourse be used, but I like vinegar as it is, cheap, safe and readily available. I left it over night with the back part of the axe sticking out, as I wanted to retain most of the scale on part of the axe and then use a wire brush to blend it into a smooth transition to the scale-less part of the axe.
Step 10: Sharpen
You can choose to do this part at the very end, but I have a cheap belt grinder and find it easiest to do the rough sharpening while the axe still doesn't have a haft. Do alternating passes until a burr forms on either side with the passes.
Step 11: Make Haft
There are many ways to make an axe haft. The traditional method is riving, but I chose to use my little band saw to cut out a blank.
Hickory is a good wood traditionally chosen for impact tools for its good shock absorbancy. Here in Australia, spotted gum has very similar physical properties, so that is the wood i chose to use.
I then went on to cutting out the top of the haft to roughly fit the axe eye before rounding and shaping the haft (equally roughly) with a carving axe, before moving onto a rasp (do get a shinto rasp if you haven't already. They are very reasonably priced and compared to normal rasps are both extremely efficient and leaves a good finish). I finished the handle with a spokeshave. This leaves a nice cut finish, and saves an enormous amount of sanding. Remember to always use the spokeshave across the grain of the wood to prevent tearouts.
Step 12: Attach Head to Haft
Keep shaping the part of the haft with a rasp or a blade where the head goes until it fits tightly. As you keep test fitting it, the axe head will leave marks on the haft, and this will show you where to remove more wood.
Cut the haft down the middle where a wooden wedge is to be inserted. Fit the head by gently tapping it on from the top, then turn the axe around and hit the handle on the bottom with a wooden mallet. Afterwards hammer in a premade wooden wedge taking care not to break the wedge. Optionally you can also fit a metal wedge across the wooden one. For this axe I made a metal wedge from a part of the cutting bit/rasp that was left over.
I would normally just do a purely friction fit axe haft (like that one time before when I made an axe haft), but since this is a bit of an odd one, I added some epoxy to be on the safe side.
Step 13: Finish Up
It's time to add the finishing touches. For this project that included getting the axe shaving sharp and giving both the haft and axe head a good coating of boiled linseed oil.
Hope you enjoyed this instructable and I hope it was helpful in either teaching you some new techniques or inspiring future projects. How about a chainsaw chain axe, or a steel cable axe? The sky is the limit and have fun with it!
Second Prize in the