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 south of Tenpenny Tower. This location contains nearly all of the parts needed 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). No Deathclaw Hand..sorry.

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 Broken Steel (DLC), Old Olney Underground (as part of Shock Value) provides practically everything you need (including workbenches and plenty of Deathclaw hands).

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. This was confirmed for me when I constructed the Bottlecap Mine even though I already had two of them that I had found; and the achievement was awarded.

A bug that pisses me off to no end: I did not receive this achievement, even though I know for a fact I made every single one of these weapons, and I have tried to figure out why; my guess is that you need to be carrying one of each of these weapons, as I am not carrying the Deathclaw Gauntlet, I had to drop it. SO, what I'm going to do is make another, and see if this achievement will be awarded, then report back. In short, my hypothesis is: You must be carrying all custom weapons at the same time in order for the achievement to be granted.


 * After researching, I still have not found a fix to this bug: I have made and I was carrying one of each custom weapon, and I have no idea why the achievement was not given. I'm thinking of contacting Bethesda and finding out about this. As of now, I don't know what causes this bug.


 * A bug-free method for obtaining this trophy is to build all of the weapons in one go, without letting the workbench be closed for over 5 seconds in between them. (PS3)


 * I found that I was only creating one at a time (creating it, checking on this wiki to find out what else I needed), and the last one I did create was the Bottle Cap mine. I already have 2 in my inventory (from doing the Wasteland Survival Guide quest) but I got the achievement without any problems. I do not believe that you need to be carrying them, because with each weapon created, I moved it into my Megaton locker. (Xbox 360)


 * I made one of each weapon over time, and when I created the final one I did not get the achievement. I then proceeded to get each weapon out of my locker and have it in my inventory, except for Bottlecap mines; I dropped those.  Then I went to the workbench and made a Bottlecap mine and got the achievement.  I don't know if you need to have them in your inventory (I don't see why you would but its too late to find out) but dropping my Bottlecap mines and making a new one did the trick. (Xbox 360)


 * Same story as above, I made my last weapon and did not get the achievement/trophy. But I just dropped the mines into my locker and made a new one and it worked. I'm guessing that if you have a found bottlecap in your inventory and then make a new one, it will not register as a new created weapon. (PS3)