Designing a Template
Determine the style of machete you would like to make; their are dozens of culture-specific styles from all over the world to choose from such as the bolo, the kukri, and the parang.
Sketch out your design onto a large sheet of paper or cardboard. Make sure the design will fit on your piece of steel and that the handle looks large enough for you to grip it comfortably.
Cut out your design and trace it onto your carbon steel bar stock with a metal scribe or permanent marker. If you are using a leaf spring, you will have to straighten it first by heating it in a fire and hammering it flat on an anvil. Once the steel has cooled, transfer the template with a scribe or marker.
Cutting and Annealing
Clamp your steel down to a work bench in a well ventilated area and fit your abrasive cutoff wheel into your angle grinder. Put on your face shield, gloves and earplugs and roughly cut out the shape of your machete, being careful to stop short of cutting into the actual design. Always point the stream of sparks away from your face and body and do not touch recently cut metal, as it will be extremely hot.
Affix your metal grinding wheel to your angle grinder and smooth any rough areas. Close detail work or sharp curves that cannot be cut out by the abrasive cutoff wheel can be honed down using the metal grinding wheel at this point, resulting in a completed blade blank, ready to be annealed.
Anneal your blade by heating it evenly and allowing it to cool slowly. This will soften your steel temporarily, making it much more workable. Light a fire in your fire pit or forge and slowly add charcoal or coal until the fire is burning very hot. Turn on your forge's fan blower or point a fan at your fire pit to make the fire burn even hotter. Place your machete blank on top of the coals and pile them around the blade.
Add more coal as necessary and continue to heat with the blower or fan. Within several minutes, your blade will begin to turn black, and after a little longer it will begin to glow in a deep red color. Move the blade and the coals around as needed to encourage a slow, even heat. Use your tongs or pliers to remove the blade. Ideally, it will be a consistent shade of reddish orange along the entire length of the blank when held in the shade. If the blade is not yet at this point, place it back in the fire, add more coal and continue to heat.
Remove the glowing blade from the fire when it has reached the correct color. Depending on the type of steel, you will either leave it in the fire and turn off the blower, allowing it to slowly cool as the coals die out, or you will simply let it cool in the air for several hours by clamping it in a vice. Check with the manufacturer of your particular steel to determine the best method for heat treating. When the blade has cooled for several hours and can be touched by the naked hand, it is ready to be worked on.
Grinding the Blade
For thicker materials, mark a line down the center of the blade's edge with your scribe or permanent marker from its tip to the hilt. Clamp your annealed blank to a table or work bench securely by its handle. You may want to use a scrap of wood as backing material so that the blade does not bend under the pressure of grinding.
Attach your metal grinding wheel to your angle grinder and, holding the abrasive surface at an angle to the edge of the blade, begin to grind out a bevel. Keep your angle consistently around 30 degrees, and make long passes over the entire length each time to keep the bevel even. The metal will get very hot, very fast, so stop frequently and wet the material with water to dissipate some of the heat. Stop grinding when your bevel reaches the center line you marked on the edge of the blade.
Turn your blade over and clamp it down to the table. Begin to grind the bevel on this side, keeping your angle consistent at about 30 degrees along the entire length of the blade and stop once your bevel meets the line in the center of the blade. Both bevels should now be separated only by the thin line you made with your permanent marker in the middle of the blade's edge.
With your blade still clamped down, mark two points along the center line of the handle or tang portion about an inch apart or further, depending on the size of your handle. Apply a few drops of tap oil and fit your 1/8th inch carbide drill bit into your drill securely. Begin drilling through the two points going very slowly to avoid overheating the bit. If the drill bit begins to smoke, stop drilling and allow it to cool before continuing. Bore straight through the handle at both points and remove any burs or rough edges with sand paper.
Hardening and Tempering
Light another fire in your forge or fire pit and slowly add coal until it has reached forging temperature. Place your blade on top of the coals and heat slowly and evenly using your blower or fan to supply the coals with additional oxygen.
Pour your motor oil into your disposable aluminum dishpan, making sure it is large enough for your entire blade to fit into. You will want the oil a few inches deep, enough to cover the blade when it has been dipped into the oil during the quenching phase of hardening. Do not overfill the pan in case it over flows. Place your quenching pan outdoors in a clear area away from flammable materials.
Remove the blade from the fire when it begins to glow red-orange, and run a magnet along the length of the blade and handle. When steel gets hot enough, it will no longer attract a magnet. Proper heat treating temperature is just a few degrees above this point. When the entire blade and handle portions do not attract the magnet, place the blade back in the fire and heat for a few extra minutes.
Grab the blade by its handle using your vice grip pliers and quickly remove it from the fire and bring it over to your quenching pan. Slowly dip your hot blade into the oil with the blade edge first. Allow the edge of the blade to quench for about 20 seconds before placing the rest of the blade and handle in the oil to quench. This process will produce a lot of smoke and possibly fire so wear large leather gloves and keep your body as far away from the quenching pan as possible.
Allow the blade to cool in the oil until it is at room temperature and then carefully whip the excess oil off with a paper towel. Spills can be cleaned up with sawdust and disposed of. Carefully pour the quenching oil into a safe container and dispose of it in accordance with state regulations. Your blade should be covered in black oxidation with bits of gray or dull white metal showing through. To determine if your blade has been hardened, take your steel file and firmly rub it against the blade material. It should slip off, removing only a layer of black oxidation. If your file is able to "bite" into the metal, then it has not been hardened properly and the process must be repeated.
Remove the black oxide layer from the entire blade and handle using your metal file and sandpaper. Any pits or dents that occurred during the heat treating process must also be removed until you are left with a bare metal blade, roughly identical visually to the pre-treated blank.
Preheat your conventional oven to 350 degrees. After heat treating, the blade is very hard, but also very brittle, so it must be tempered in an oven to bring out some of the steel's natural flexibility. Place the blade in the oven in the middle rack and allow it to heat for about an hour.
Check on the blade frequently. A layer of colored oxide will begin to develop, the color of which roughly indicates the temperature of the steel, going from light yellow to straw yellow, to brown, to purple to dark blue. You want to maintain the straw yellow color for the entire hour, so the oven temperature might need to be adjusted. If you allow the blade to develop a purple or blue oxide, the temper will be on the hard side, creating a harder, less flexible blade.
Allow the blade to cool once it has tempered for an hour and then repeat the process to ensure that the steel has fully taken the temper.
Hone down the bevels on both sides of your blade until the edge is sharp. You can do this using a file, lining it up with the angle of the bevel and drawing it down the length of the machete, or you can use a belt sander or angle grinder with a sanding wheel. If you use a power tool, the blade will heat up very quickly, which will ruin the temper and hardening, producing a weak blade. When using a belt sander or angle grinder, only grind for one second at a time, then cool the piece with water. If the steel begins to develop a colored layer of oxide or is too hot to touch with bare hands, it is getting too hot and must be cooled back down.
Switch to a coarse-grit sandpaper when most of the extra edge material has been removed. You may wish to glue the sandpaper to a very flat surface and draw the blade across it at the appropriate 25 degree angle to hone the edge.
Repeat this process on the other side of the blade until the edge is sharp enough to cut paper and the bevels are smooth and even.
Creating the Handle and Finishing
Trace the outline of your machete's handle onto your 1/4 inch hardwood scales and cut the piece out with your jigsaw. Turn the handle over and trace the other side onto your hardwood scales, and cut this piece out as well.
Line one of the handle pieces up with the corresponding side of your handle or tang portion to make sure it fits.
Mix a dime-sized amount of epoxy cement with an equal amount of hardener for about 60 seconds or until thoroughly mixed.
Spread the epoxy cement onto one side of the tang or handle portion of the machete and then apply the corresponding hardwood scale. Adjust it so that the edges line up with the edges of the tang and then clamp the piece in place and allow the cement to set.
Drill the rivet holes once the first scale is in place. Fit your 1/8 inch drill bit into your drill and clamp your blade down to a work bench with the wooden scale underneath the blade and the unfinished side of the tang pointing upwards. Bore through the already drilled rivet holes in the tang and into the hardwood scale on the other side.
Mix another dime sized portion of epoxy cement with an equal amount of hardener and spread it along the unfinished side of the tang. Attach your other hardwood scale to this side of the tang and adjust the fit until the edges line up against the tang. Clamp the scale in place and allow the cement to set.
Remove the clamps from the wooden scales. Turn your blade over so that the scale which you drilled rivet holes through is facing up. Clamp the machete in this position. Drill 1/8 inch holes through both of the pre-drilled rivet holes, going all the way through the holes in both scales and the tang. The rivet holes should now go all the way through the handle material.
Use a countersink bit with a radius of the same size as the caps on your Chicago screws or cutlery rivets to create shallow countersinks on both rivet holes on both sides of the handle. Screw your Chicago screws into place or set your cutlery rivets with your hammer and anvil. You may also apply epoxy cement to the screws prior to entry to create a permanent fit.
Use your sand paper, angle grinder and belt sander to round off the edges of the hardwood scales, and remove excess material until the edges of the scales are flush against the metal tang, creating a comfortable and ergonomic handle.
Finish your handles with several coats of polyurethane to seal the wood and allow to dry for at least 24 hours before use.
Things You Will Need
- Carbon steel bar stock (O1 or 5160), leaf spring or crosscut saw blade, 12 to 24 inches
- Angle grinder
- Abrasive cutoff wheel
- Metal grinding wheel
- Bench grinder
- Metal Scribe
- Permanent Marker
- Firewood and kindling
- Blower fan
- Fire pit or forge
- Tongs or large vice-grip pliers
- Disposable aluminum dishpan
- Metal file
- Motor oil
- Electric drill
- 1/8th inch drill bit
- 1/8th inch steel or brass rod
- Countersink bit
- Wet/dry sandpaper, 1000, 400, 320 and 200 grit
- 2 cutlery rivets or Chicago screws,1/8th inch.
- Tapping oil
- Epoxy cement
- Conventional oven
- 1/4 inch hardwood scales
- Gun blue solution
- Face shield and goggles
- Leather welder's gloves
- Fire extinguisher
- Carbon steel is very tough and will take an excellent edge, but must be cleaned and oiled regularly to prevent rust and corrosion.
- Depending on the type of steel you are using, the heat treating process may be different, but for most carbon steels the process is largely the same.