Many teams elect to ignore kits entirely and instead make their own mechanisms completely from scratch. While this allows for nearly unlimited design freedom, keep in mind full Custom has many caveats and drawbacks. A full CAD model is required for a custom robot, as well as machining capability. Custom robots are not suitable for a new team.
However, forgoing a full custom robot opens up many opportunities. Many teams choose to create a robot that is a mix of kit parts and custom parts. Our recommendation is to use kit parts as the backbone of the robot, and custom fabricate any additional parts necessary, instead of the other way around. That way, you can rely on the strength and durability of the kit while retaining the ability to customize small pieces and mechanisms to your advantage.
The methods that teams use to make custom parts typically involve either additive or subtractive manufacturing: either building a part from raw material (3d printing) or removing material from stock to create a part (Milling, Routing, and Laser Cutting).
You can now find details on 3d printing and milling in our Custom Manufacturing section, with tutorials and general tips to help bring your parts from CAD to real life.