WARNING: SHURIKEN ARE DANGEROUS! MAKE AND USE AT YOUR OWN RISK. THESE ARE BANNED IN SOME COUNTRIES. THEY ARE FUN!
Step 1: Materials
Step 2: Tools
P.P.E. Safety Glasses and Gloves
Something to mark with. I used a Sharpie
Something to cut metal. I used a hack saw, but a band saw would make it easier. Just make sure it has a metal cutting blade.
Something to smooth and sharpen after the cuts. I used a file, but a grinder would really make quick work of it.
Something to hold the sprocket while you cut and file it. I used a Workmate clamping table, but a table vise would hold better.
Sounds like I need more tools, but that is what it is about, working with what you have.