Location: Megaton - Craterside Supply (Moira Brown)
You can buy this schematic from Moira Brown, the proprieter of Craterside Supply.
Location: Tenpenny Tower (Herbert “Daring” Dashwood)
You’ll find Herbert wandering around somewhere in Tenpenny Tower, either in the Federalist Lounge in the Lobby, or in his room in the Suites. He’ll ask you to tell him if you find Argyle ever. If you went to Rockopolis (for instance, to find the Bobblehead - Unarmed) then you undoubtably have found Argyle. Tell Herbert about his friend and he’ll give you a key to his safe. The safe is in his suite, in the north-western room. Inside is the schematic, amongst other toys.
Location: Jocko’s Pop & Gas Stop
You can find this Schematic in Jocko’s Pop & Gas Stop, on a work bench. Jocko’s is just east of Girdershade and north of the VAPL-66 Power Station.
Location: Little Lamplight (Knick-Knack)
You can buy this Schematic from Knick-Knack, the kid who runs the store in Little Lamplight.