Weaponsmith

 is a Fallout 3 achievement on Xbox 360 and PC and a trophy on PlayStation 3.

It is granted for constructing one of each custom weapon. Those are:
 * Bottlecap mine
 * Dart gun
 * Deathclaw gauntlet
 * Nuka grenade
 * Railway rifle
 * Rock-It launcher
 * Shishkebab

Bugs

 * Sometimes after you have made each weapon, the game doesn't give you the achievement/trophy. However, this may be due to finding one of these weapons rather than actually constructing it. The bug can be resolved taking all the components and making all the weapons in one time.