Fallout 3 crafting

Schematics allow you to create homemade weapons, provided you have the proper components.

Acquiring multiple copies of the same Schematic will allow you to make better versions of the self-created weapons. Each copy you find past the first one allows you to make a better version (ie; Rock-It Launcher v2).

It's a good idea to hunt down additional copies if you plan on using the weapons often. If you gain a second schematic the weapons damage improves by 10%(v2). If you gain a third schematic the weapons damage improves by another 10% to a total of 20%(v3). Additional Schematics for Bottlecap Mine and Nuka Grenade allow you to make more instead of giving more damage. With one schematic - you make one. With two - you make two. With three - you make three.

Note additional Schematics cease to yield benefits after three of each kind have been located.

Higher repair will allow you to potentially make homemade weapons that have higher starting condition and damage. As you make multiple copies of the same weapon you can combine them with the repair skill for higher condition and damage. Alternatively you can have an NPC repair them to about 54% max. Note - Bottlecap Mine and Nuka Grenade are always max condition and rely on the explosives skill for more damage.

Appearances
Schematics appear only in Fallout 3.