Wired magazine did a review of the ax below.
I'm gonna tell you how to make one yourself for the system D economy.
First off there are many methods to make this but for the purposes of this article, I will only cover the most economical for low volume production.
The head is CNC cut steel plate and bent on a press brake.
Now you could use stainless for this and skip the powder coating and heat treating. Stainless starts out soft, but it work hardens readily. It's harder than mild steel to start with.
If you are outsourcing this part, go with mild steel 1/4 plate and CNC plasma.
You will have to know how to draw this part in CAD. Measure it, draw it as a flat part and mark the bend lines in the file. You can put notches marking where the bends go to save a ton of layout time.
It will run you between 1-2 dollars for the cutting and a sheet of 1/4 inch steel plate or 6mm will cost you around $150 USD stainless will run you more.
This is what a small CNC plasma table looks like.
Next is the bending.
You can send it out or make a home made press brake for a shop press and angle bar.
Benders work like this
Outsourcing at the most will be a dollar per bend and that is crazy expensive. Usual costs are around 25 to 50 cents per bend.
This one has 4 bends.
Sharpening, you can sharpen it on either a surface grinder or for our purposes an angle grinder and steady hand. Go easy, don't over heat the metal. Start out with a rough grinding wheel, finish with a flap disc.
Heat treating, use motor oil or sugar and a torch. Case harden it like a knife. Same method.
Handle, a length of steel pipe.
Powder coat it or paint it and get some of that spray on rubber coating they use for bed liners to use for the handle.
Sell them at your local flea market/hardware store/Craigslist.
10 minutes of drawing got me this half baked representation working from memory only,