You can "mine" steel bars from the large streetlights around gas stations and public buildings. Another good place is the trailer lights. Build a nerd tower or fly up to the lamp itself and salvage with the wrench. Note the two posts without lights but with the metal crossbar. You can always find one of these crossbars on the ground in the junkyard close to the dumpsters.
However, you still need the steel tools schematic which is very hard to find. If anyone can locate a loot site, please post that info.