Seeing as how this conflict of utility will ultimately make weight savvy Apocalypse survivors have to do the unthinkable and choose between carrying weapons or tools, it occurred to us what the world really needs are tools that can also be used to help take on a horde of Zombies.
Perhaps one of the more useful tools I have ever owned was a flat bar with a series of hexagonal cutouts in it. While minimally useful as a wrench because of its long length, it proved invaluable as backstop for holding nuts in place while I was tightening them down. Not to mention that when my wrench set was annoyingly missing just the size I needed, my hard to misplace flat bar always had me covered.
It therefore stood to reason that a Katana with a similar series of hexagonal cutouts would be valuable both for taking down Zombies/Mutant wildlife and complementing any set of tools used for post apocalyptic DYI projects. However, after a bit of research it became apparent that in addition to being expensive to make, “Katanas are notoriously high maintenance”* and at ApocalypsEV we hate the idea of high cost high maintenance (www.ApocalypsEV.com).
So seeking a simpler more affordable concept, we created the Mechanics Machete. It combines the Zombie fighting power of a machete with the utility of a set of wrenches. Also when using stainless steel for the blade, it eliminates the maintenance hassle of trying to keep the blade rust free.
Step 1: Parts & Geometry
So to save on time and add simplicity the Mechanics Machete was created to use the handles and sheath from a store bought machete. Specifically, it uses a Harbor Freight tools machete (http://www.harborfreight.com/18-inch-machete-with-nylon-sheath-94154.html), which is both affordable, and features plastic handles that won’t rot like wood ones can.
The blade profile needed to create the mechanics machete either by cutting the hexagon profiles in the stock 14GA carbon steel blade that came with the machete or, more preferably by cutting a new blade out of stainless steel can be found in the DWG file attached to this page. If you don’t currently have a CAD program installed to view/edit the DWG files, I recommend the free Draftsight DWG editor (http://www.3ds.com/products/draftsight/overview/).
The attached DWG includes the blade profile and hexagon cutouts for 9mm nuts/bolts up to 25mm nuts/bolts in 1mm increments. Due to the 1mm increments, this “Metric” blade also works with all major “English” nut/bolt sizes up to 1inch.
You can of course make your Mechanics Machete using any brand of off-the-shelf machete you choose. Just simply take off the handles, trace the blade on graph paper, and then draw it in some sort of DWG editor. Then when you have the profile drawn take the specially drawn sockets from the attached DWG and add them to your blade design.
If you plan to draw your own sockets, you should note that you can’t just draw plain hexagons as Laser/Plasma cutters typically don’t like to create sharp corners. So to fillet the corners without affecting the base “Wrench Size” you have to draw a 1.5mm(1/16in) diameter circle in every corner and fillet it into the hexagon with .75mm(1/32in) radius fillets. Also if you want to make a cutout for a 32mm sized nut, you can’t draw the hexagon exactly 32mm as such a perfect fit will most likely not work. Instead, you need to add .05mm to .1mm to the base nut size. The easiest way to figure exactly how much to add is of course to find a 32mm socket or wrench and measure it with a pair of calipers.
Step 2: Cutting the Blade
To cut a new blade out of stainless first make sure that your selected material is at least 16GA(.0598in) thick and not much thicker than 10GA(.1345in). Any thinner and the blade will bend to easy, any thicker and it won’t cut effectively. I prefer 10GA(.1345in) stainless as I typically use my machetes more for their blunt force rather than sharp edge when chopping up kindling/branches or other such task; also the thicker the blade, the more durable it its as a wrench.
As for cutting the blade I should note that if possible you should try and get a hold of a laser cutter as their higher cutting tolerances are more ideal for cutting the specifically sized hexagon shapes needed to turn nuts/bolts.
Once your machine and material have been selected, simply clamp down your material, zero the machine, and let technology do in 3 minutes what might take over a day to cut by hand.
Step 3: Deburring the Blade
My preferred solution for deburring is to first start with an angle grinder or other sander get the edges with 60-80 grit course sand paper. Then take a dremel tool or file and clean out the burs on the internal contours. Then as an optional cosmetic step to get rid of the sanding marks take a random orbit sander with 180 grid fine sand paper and sand both sides of the blade.
Also plasmas cutters often have tendency to not cut smaller holes out accuracy, so you might to finish drill out the mounting holes out with 7/32in drill bit in order for the blade to fit back on the handle.
Step 4: Preparing the Handles
To add the screw post you first have to remove the old plastic stand offs. I find the fastest way to do that is to first take a hand drill with a 5/16in bit or larger and simply drill them flush with the blade. Then with the blade out of the way take a razor knife and trim off any excess plastics so the new blade can fit flush. Then take a hand drill with a 7/32in drill bit and drill out the three screw holes on each side of the handle.
Step 5: Sharpening the Blade
If you are going to sharpen the blade yourself the first thing you need to determine is how sharp you want the blade to be. It might seem obvious that an ultra sharp edge might seem like they way to go, but remember the sharper the edge, the quicker it dulls. Since I tend to use my machetes more for blunt force task, rather than precious cutting ones I typically have a steep kinda dull edge that rarely if ever needs sharpening.
To create that edge I start by taking a brightly colored marker and mark in about 1/8in on each side of the blade all the way down its length. Then after securely clamping the blade down I take my grinder and grind at an angle that will grind from the inside edge of the marked line to the center of the blade edge. Make sure to take several grinding passes to reach this angle (about 10 to 15+) rather than trying to grind it all off at once. If you grind correctly on both sides (it takes some trial and error), then the marked line will disappear, and each side will meet in the middle of the blade. I typically find it helpful to split the curved section of the blade, and the flat section of the blade into two different sharpening zones, which is to say that I will take a few grinding passes at the curved section than take and equal number of passes on the straight section.
Now 1/8in back is what I use for creating a dullish blade, so if you decide you want a sharper blade start by marking further back (.25in for regular sharp and .375in for ultra sharp), and then grind at a the subsequent shallower angle. Also when creating sharper edges I find it helpful to run the blade thought a knife sharpener when I am finished grinding (http://www.harborfreight.com/handheld-knife-sharpener-94620.html).
Step 6: Finaly Assembly
You will then have a mechanics machete** fit for fighting Zombies, and rust*, should the Apocalypse come!
*The last photo is what happens when a regular machete and a stainless mechanics machete are left out in the rain
**If you want to order an already built mechanics machete see our online store at http://apocalypsev.com/?page_id=47