Ok. Level Up uses an expanded version of the artisan tools rules as its base. The Artisan's Tools and Profession Checks table (Adventurer's Guide page 338) lists each tool (expanded from the PH), the material and amount each tool needs to produce items, the time is takes to make an item, and the value of the item made based on the DC of the profession check made with the tools.
This is for making trade goods. The armor table (AG 319-320) explains what artisan's tools are need to repair armor, and the DC to do so, and the Materials table (AG 322-323) lists different materials by weight and cost multipliers, any properties it might have, and repairability (DC to repair and tools needed).
For actually crafting items of use we go to Downtime activities (AG 426). Crafting is a downtime activity that requires time and materials that vary based on what you want you want to craft, what materials you are using, and what quality of item you want to end up with when you're done. For weapons and armor (including shields), there are several enhancements that can be used when crafting to modify and enhance, for additional money and/or time (and possibly a higher check).Relevant tables in the same section provide the needed information. With Level Up's Engineering skill (which also covers technology depending on the setting), these rules can be used for large projects like buildings, vehicles, siege weaponry, and more.
From Mage Hand Press's Complete craftsman I draw the Craftsman class, which I have modified to fit better with these rules and which generally makes a lot of these checks either easier or take less time or money. The class also provides easier access to rare weapons and armor (as per the equipment chapter in the AG) as well as a lot more optional enhancements to be added to these items.
Level Up's recently Kickstarted Voidrunner's Codex expands these rules to cover futuristic items, including space ships.