Introduction: Cleaning and Refurbishing a Machete
Other than the tools; all the materials were salvaged from the trash. I don’t forge blades, I retrieve knife steel from discarded knives tossed out to the waste bin and fix them so that they are a serviceable blade. Most of the time I only need to clean, sharpen, and make a new handle for the blade. However there are times like this machete where it has been so abused and poorly maintained it needs to be reprofiled.
I did not intend to make the machete look like a bowie knife; but damage to the tip and adding the guard did just that. Now off to blade anatomy.
Step 1: Blade Anatomy
Surprisingly all blades like knives have anatomy; knowing blade anatomy can prevent you from being defrauded. I once saw a replica Roman sward in an antique store, it was ladled real 600 bc Roman sward $1200,oo. I told the owner of the store it wasn’t a real Roman sward, it was a replica worth only about $20,oo. He asked me how I knew so I removed the nut at the pummel end of the handle telling him the Romans didn’t have taps and dies. He asked me how did they hold the handle on. I took my knife out and showed him, they peened or pinned the handles on.
So here are some blade anatomy pointers; so you can tell cheap from quality, and understand the terms when I use them.
Step 2: Tools and Supplies
This project took a surprising number of tools.
Dremel & attachments
Belt Grinder for a belt grinder I used my belt sander loaded with a coarse grit belt and mounted the sander to my work table.
Wire Brush for Hand Grinder
Fine and Coarse Files for sizing pins.
Five Minute Epoxy
Caliper or a Micrometer
Scrap brass for the pins and the guard.
TV antenna for a hollow lanyard pin.
Handle scale material; normally I would use wood or bone. However since the pin holes in the full tang are in a straight line and could split the handle scale, I used the ¼ inch thick plastic from a cutting board salvaged from the trash.
Step 3: Assessing the Machete
I started by removing the black electrical tape so I could see what was left of the handle.
Once I could see the handle material and steel rivets I could see none of the handle material was salvageable.
Clamping the machete in a vice I used the hacksaw to cut the rivets and remove the handle material.
Step 4: Cleaning the Steel
Do not use a grinding disks or belts to remove the rust from the steel, they remove too much of the good metal. Clamping the blade to my work table, I used a wire brush on my hand grinder to remove the rust and inspected the steel.
Other than some pitting on the tip the steel was good.
Step 5: Reprofiling
There were two defects to the blade and three improvements to the handle design I wanted to make.
Rust caused pitting at the tip.
Over sharpening caused a dip in the edge belly.
Sharp corners on the handle can injure your hand.
Since you swing and whack with a machete I wanted to add a lanyard pin.
I also wanted to add a hilt guard.
Before I started reshaping the handle; I used the plastic blade guard from windshield wipers taped to the blade edges to insure I didn’t cut my hand.
I increased the size of the one pin hole with a small grinder attachment dremel for a lanyard pin.
Using the belt grinder I ground the full tang 1 mm smaller in the top and bottom to fit the guard then rounded the sharp corners.
To remove the pitting in the tip; I had to change the tip geometry from a Strait Back to a Drop Point or a Clip Point. Changing the point to a Tonto or a Sheepfoot would be too much work with the hardened steel. I chose to make the machete a Clip Point.
To remove the dip in the belly of the blade I ground the high spot at the Ricasso.
Step 6: Making the Guard
To make the guard I took a flat piece of brass and holding it in a vice I cut a slot in it with the dremel.
Next I used a flat pin file to adjust the slot until the flat piece of brass fits tightly at the blade end of the tang.
Once I was happy with the slot in the guard; I clamped a couple pieces of scrap handle scale material to the tang as a reference, and ground the guard to shape on the belt sander.
Last I polished the guard so there were no sharp edges.
Step 7: Pins
Again made with brass salvaged from the trash; pins can be made out of anything from wood to steel. There are three basic pins, solid, mosaic, and hollow or lanyard pin. I am going to use four solid pins and one hollow pin.
I am going to resize my brass using a drill press and files to fit my pin holes. Remember drill chucks are rarely perfectly centered so do not adjust the pin after working on it in the drill press or else the finished pin can be crooked.
Step 8: Sizing the Pins
I use a drill press as a lath. Since the tap cores have a threaded hole in the end I mounted the cores in the chuck and used a hacksaw to part off the threaded end of the tap core.
Making sure I have long enough pin I used a coarse file to grind down the diameter of the spinning pin and a fine file for a smooth finish.
I would stop the drill press every once in a while to measure the diameter of the pin top and bottom.
I continued to file and measure until all the pins are the right size for the pin holes.
Step 9: Fitting the First Scale
With the guard in place clamp a scale to the tang tightly to guard.
Then drill the first pin hole in the scale.
Place a pin in the hole to hold the scale in place and drill the second pin hole.
Place a pin in the second hole and drill out the remaining holes.
Step 10: Fitting the Second Scale
Clamp the first scale to the second scale matching the guard end of the scale.
Drill the first hole in the second scale and place a pin in the hole to hold the scales in place.
Drill the second hole in the second scale and place a pin in it.
Last drill the rest of the holes.
Step 11: Shaping the Scales
Temporally attach the scales to the blade without the guard with two pins.
Shape the scales to the tang on the belt grinder, the Quillons are too small for the belt grinder so to shape the Quillons I used the dremel and a sanding bit.
Last I reassembled the handle with the guard and checked the fit.
Step 12: Finishing the Handle
Take the handle apart and glue the scales to the tang with five minute epoxy and insert all the pins including the hollow lanyard pin.
Trim the pins level with the scales and sand the scales to a nice finish.
Step 13: Sharpening the Blade
Machetes are whackers; you swing them into brush and vines as you hack your way through the forest. The machete blade is very thin, only 80/1000 of an inch, with the wrong edge geometry the hardened steel can break easily. This limits the choice of edge geometry to a strong Convex edge, or a small micro bevel V grind. There is too little material in the blade for a compound grind or a hollow grind.
Using the belt grinder I ground a convex edge into the blade making sure the plunge lines are even at the Ricasso.
Last I gave the cheek of the machete a nice buff with 800 grit sand paper.