This project was inspired by a family I stayed with in Kenya. The only utensil they had was a sharpened butterknife shared by about twenty people.
Select your "blank":
Test your butterknives by bending the blade with your fingers. The farther you can bend it without it staying bent, the better it is.
Instead of a butter knife, you could use a saw blade or any piece of metal.
WARNING: I will be showing a bunch of OPTIONAL steps using tools.
For purist "no-tool" knifemaking, just skip all the steps using tools.
Or just substitute "with a rock" for the name of the tool.
Your knife will be fine.
Step 1: Optional: Drill Holes in Each End of the Handle
Skip this and the wrapping is the same and 95% as good.
Step 2: Optional: Countersink and Smooth the Holes
This will keep the burr on the edge of the hole from biting the cord or your hand.
Step 3: Optional: Melt and Taper the Cord End
Get your fingers wet so the melted plastic won't stick and burn you like napalm.
This is 1/8" nylon "parachute" cord. 1/8" Polyester is better because it doesn't get loose when wet. Get it at a chandler. (marine supply)
Step 4: Start Wrapping
If it's cotton or other cellulose fiber, make sure it's dry first.
Nylon shrinks when it dries, cotton shrinks when it's wet.
You don't really need the hole, that's just something to make it look less like a butter knife.
If you drilled holes poke the cord through one of the holes.
Leave a tail a few inches long.
If you skipped the hole just lay down the tail and wrap over it.
Wrap over the tail until you get halfway up the handle.
Step 5: Lay Down a Loop
To do that we'll lay down a loop of thin cord and wrap over that.
Step 6: Put the Tail in the Loop
If you drilled a hole poke the end of the cord through it.
Put the end of your cord through the loop.
Step 7: Pull!
Pull the tail of the wrap cord under the turns of wrapping.
Step 8: Pull the Tails Tight
Otherwise use a stick.
Twist and pry on the tails to tighten them.
Step 9: Handle is Finished
It looks and feels good.
Step 10: Design Your Blade
Decide what you want and first mark, and then scratch that shape in your blade.
I'm going for an asymmetrical bonsai-utility tip.
Step 11: Shape and Rough Sharpen the Blade
I rubbed the blade on the edge of a curb til it was cut through enough to break off at the length I wanted.
Then I rubbed the rest of it on wet pavement til it was sharp and there was a bit of a burr on the edge.
It goes pretty quick. Cement is a good abrasive.
Look for smoother concrete if you want a better finish on your knife.
Or rub a rock or piece of cement on your working abrasive surface to smooth it first.
A rock, brick, broken flower pot, or any other rough ceramic item make good abrasives.
Hard wet beach sand can be a miraculously good abrasive.
The blade got a bit hot even though the pavement was wet.
I dipped it in a puddle from time to time to cool it off.
Step 12: You Have a Knife!
Here's how to make a paper sheath so you can carry it safely in your pocket.
That was quick!
It took less than an hour according to my photo EXIF timestamps in spite of interruptions such as rain and repeatedly hitting my camera with a hammer (canon s30 "E18 error").
Use your knife safely!
As my Granddad used to say, "Don't cut toward yourself and you'll never get cut!"