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

Strategies
Probably the easiest way to obtain all of the parts necessary to build all of the custom weapons is to go to Lucky's southwest of Tenpenny Tower. This location contains nearly all of the parts needed (except a Deathclaw Hand) to make every single custom weapons (If you don't mind a little Karma loss; the parts are marked as "owned" by the scavenger there and no he will not sell any of that to you).

You can also try Dr. Horace Pinkerton's lab located in the broken bow of Rivet City, it contains a lot of the parts, all you'll need is a stealth boy to steal it all. (Results in negative karma)

If you have the Broken Steel add-on, Old Olney Underground (which you will visit during Shock Value) provides practically everything you need (including workbenches and plenty of Deathclaw hands).

With Broken Steel, at level 26, you can take the Warmonger perk, which makes all custom weapons available to you, without having to find their schematics. This can be a big help if you want to get this achievement without having to search all schematics.

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.


 * A bug-free method for obtaining this achievement / trophy is to build all of the weapons in one go, without letting the workbench be closed for over 5 seconds in between them.