Although the Challenge 420 cutter is strong machine, some parts are a bit less durable. Continuous cutting dulls sticks and knives over time, after many uses. So, to help your 420 continue to make sharp cuts, take of its parts. If you don't see the part you were looking for, don't worry! We have a full inventory of parts, and we're ready to help you find just what you need. If you need assistance call 800-243-9226 and ask for our Parts Department.