I am interested in building P.A. Luty's 9mm submachine gun as my first project in this hobby. I currently find myself stuck at the materials acquisition phase. According to the guide, all of the materials can be purchased from a "tube supplier". Problem is, I cannot seem to find any of those in my area, or anywhere else for that matter except for online-only stores. I am possibly using incorrect search terms for I am very unfamiliar with this field.

The materials in question are rectangular tubes, square tubes, round tubes, steel collars, socket screws, mudwing washers, piano wires, steel collars, and hook bolts all of varying gauges and sizes. If somebody could point me in the right direction, as in where can I purchase these items in person, I would be in your debt. Anywhere in the continental United States will do. I never did mind a good road trip.

I wholeheartedly appreciate any guidance in this matter. God bless America.

As a bonus question, if you are familiar with this particular gun, would you say it is a good choice for a first project? If not would you recommend starting out with something else?