Hmmm. Set the Wayback, Sherman!
Guess it was back in '94 when I "got a clue". The premise being that they couldn't ban what they didn't know about! Started out "easy" with a FAL, then a 1911, then a 1919A4, then a DShK...get the idea?
My tooling isn't all that elaborate, but the array of tools seems to expand each time a new project is started!

Still holding out for a (cheap) West Bend lathe! Have had no formal machinist training other than The College of Hard Knocks.
Right now the shop contains a benchtop mill (R8 shanks), heavy 10" vise, 20-ton press, assorted files, punches, hammers, TIG rig, blast cabinet, compressor, park tank, and LOTS of shelves, bins, racks, and drawers! The shop has peg-board on every wall - and they are FULL of stuff!
And lets not forget the obligatory DREMEL! About the only tool in any shop that can destroy as easily as create!
And a couple of nice bigs safes to put the finished items in.
To build any gun the one thing you MUST have are blueprints/drawings AND the latest copy of the BATFe regs - read it and understand it(which is a big stretch for anyone!).
Before I go any further, let me make the distinction (my own opinion) between ASSEMBLING and BUILDING. One assembles a gun using parts already made - including the receiver. This would be FALs, ARs in some instances, and the like. With these all the "hard work" is already done. Building, otoh, entails making or modifying parts, and making or rebuilding the receiver.
Example: You can assemble an AK using all "store bought" items, OR you can build an AK by making your own receiver (not those putrid flats everyone sells!), and making/modifying your parts - within reason of course.
Anyhoo, the things you cannot skimp on are: Dial Calipers, headspace gauges, and...METAL.
You might get away with using some elcheapo stuff from TSC, but you'll quickly learn to appreciate craftsmanship and a job well done. Yes quality metal will cost more - sometimes as much as three times the cost of the cheap stuff, but it will last much longer and hold its finished appearance (low carbon steel won't hold a blue worth a darn). The metal of choice is ASTM 4130 and 4140. Each has its own properties, both are heat-treatable, and are hard as "nails".
Will continue as time allows - until then!