Menash Signatures had a great Sheaffer repairman’s kit on his table at the Philadelphia show this year - a great, heavy oak box with a metal "Sheaffer’s" plaque mounted on the lid. Inside the box were all kinds of repair parts and tools for fixing early Sheaffer fountain pens. Although I’m no pen expert, it looked to date from the 1920s.
But laying in the upper tray were these odds and ends, which were significantly younger and didn’t have anything to do with pens:
The lower piece is a Sheaffer Fineline cutaway demonstrator mechanism, which were included in salesman’s sample kits.
The black piece is the upper barrel from an earlier Sheaffer "working togs" pencil, with an interesting feature:
The screw is for advancing the eraser. On most of these, the entire top half of the barrel is removed, and the screw is mounted on the end of the mechanism. On this early example, the advancing screw was mounted in the top half of the barrel itself, accessed by removing a short top piece that is long gone by this point.
And as for that other piece:
I have no idea what that is or what it’s supposed to do.