FRK Schematics (A18 and A19) gives you a workstation for 7 Days to Die - a dedicated space where you can craft mostly mod schematics, as well as some weapon and item schematics. This is especially useful if you have a specific mod, or item, or weapon in mind that is not yet available, not yet created, for this specific game -

As long as you have a copy of the desired weapon or item mod, you only then need this workstation, some paper, ink, calipers - and you can reverse engineer the mod you so desire, write down the process, the mechanics, and, with the help of this tool, learn how to assemble it all together.