I've been away for some time due to college but I am back now with a video tutorial on how to cone wheels!
-Rotary tool with polishing felt: The felt is so the wheel rolls on a smooth surface while operating.
-Pliers or wirecutters: This is to hold the axle with one hand and the other works on the wheel.
-Utility blade: These are the best ones to use because of how durable they are and their sturdiness keeps them from bending so you will get a consistent cut.
-Eye protection: Always wear it! No exceptions!
Video tutorial: youtu.be/de4uJN7eiVk