This project, like so many others, came to me while I was working on something else and uses an idea that I’d wanted to try for some time. The job I was doing was breaking out the concrete walkway in front of my house and using my shovel to pry the pieces up and apart, when the tip of the shovel cracked:
I could have repaired it by cutting away the damaged part, but that would make it quite a bit smaller. Also, I had another shovel in good shape, but with a broken handle, so I just took the handle from this one and used it on that other one.
Then I got to thinking about what I could do with the broken spade. The steel is of good quality, hardened and tempered so it could hold a reasonable edge. Along the sides it is fairly flat, so I figured I could get a fair sized knife from it without having to do much flattening.
For the handle, I thought it would be interesting and somewhat fitting to use the broken concrete that was the cause of the break in the first place:
I used a diamond tipped blade in my mini-grinder to make the cuts and smooth the pieces as best I could. These blades are reasonably cheap and easily cut through concrete and stone quickly. The blade is cut out to rough shape, flattened on the anvil and glued to the handle scales with fast setting epoxy:
I drilled a few holes through the blade tang to better anchor the handle, since I didn’t think that pins would be practical here. The concrete is hard and brittle, with larger pieces of very hard (granite) stone that would make drilling through a risky operation.
Next came a lot of shaping using the diamond wheel and my belt grinder. I was surprised that the belt grinder with just a normal aluminum oxide belt could be effective with the concrete. Certainly, a belt made for stone would work better, but I was able to achieve acceptable results:
With the handle done, I could shape and polish the blade. It has my favorite full convex grind. The blade length is 4″ and the shape is known as drop point, it curves along the spine from the handle to the tip. I gave the handle two coats of clear spray finish to keep it clean and bring out the beauty of the ground concrete:
Not bad at all, considering what it started out as. The original idea for using stone for a knife came to me over two years ago, on a drive up north to a job. I noticed all of the interesting rock blasted out when they improved the highway and thought it would be neat to stop, grab one and make the handle of a knife from that. Still a definite possibility.
Watch the video below showing the build from start to finish.