My wife wanted a Chopping Knife since forever while she was nagging about something I've scrolled through instructables... Accidentally I said Yes to something.

The idea was to build one out of a old sprocket from my bike. It Took me something about 3h to build it. I was supplied with two coffee from my wife and used only standard tools like a drill and a angle grinder.

Step 1: Find Some Sprocket

I dive something like 5000-6000Km every year with my bike. These are 3100-3700 freedom units. The chain and sprocket are changed ~once a year.

For this projekt I'm using a SRAM x12 set...

Step 2: Preparing the Sprocket

... especially the 50 teeth (the biggest). Therefore the rivets needed to be removed. Then the sprocket was mechanically cleaned halved.

Step 3: Grind Away the Teeth

For the cutting edge we need to remove the teeth.

Step 4: Sharpen the Blade

To ease the process of having two identical parts I've used some screws to hold everything together. Then I've used my angle grinder to grind on a first edge. With a sharpening stone I've finished the sharpening for now. (I'll try to harden the blade in the future to further increase the sharpness)

Step 5: Crafting the Handle

As a handle I'm using some V4A steel which i found in my garden... don't ask. To mount the handle to the sprocket the same holes like the rivets before were used.

Step 6: Stiffen the Two Blades

To make the two blades as stiff as possible I've cut down some brass tube and added some screws. This way I have more then enough structure added and it feal like a solid pice of metal, zero flexing.