Jeff,
Thanks for showing your pictures. It's nice to see pieces that look the same!
I am obsessing over details and micrometers and at the same time I have been wishing for more control on the lathe. An eighth of a turn, a bump of a handle, turning the wrong handle only just a bit, etc. can cause the piece to be almost worthless. I imagine CNC turned pieces and drool over that imaginary precision. At least I know RCA wasn't using them.
This was really my first time turning metal on a lathe. It is hard work, and worth it. I did save money, but also had to buy enough stock, and a few tools. Thank goodness for good, trusting friends with tools!
In my photo of the tube on the white bricks, those bricks are fire bricks from a kiln. They're good to trap and reflect the heat, and make everything even when annealing. I had help torching the rod with portable torches: one person passing slowly over the brass from the outside in, meeting in the center, and not moving in until the section you were hovering over was a nice dark cherry red. It's good to get the hottest part of the torch right over the brass. It was helpful to anneal in a non-well lit room so you can see the glow. You can quench the tubing in water, or just let it cool by putting it on cold steel or concrete and letting it sit. I found the less handling caused less dings. It's not easy managing a glowing hot tube of brass. The brass will then be workable. The hand bending was pretty easy. I would not use any mallets or clamps, or you might get some marring and crimping.
The tubing is brass 260 (only O.D./thickness match at McMaster-Carr) and the solid brass is brass 360
I have not cut the slits yet. It's nice to know a good thickness to use. I wonder if using a jeweler's saw will be more precise than a slit saw. I assume you're using the slit saw blade on a milling machine?
Oh, it seems that the annealing will expand the metal a bit, so the base piece that oh-so-perfectly fits in the pitch antenna tube will probably not fit that way in the loop antenna tube. I am holding off on trying to get those pieces to fit until I have done more tube work. Also using a pipe cutter will squeeze in the wall a bit. It's nice to face off the straight pitch tube on the lathe, but you can't have that option on both ends of the bent loop tube. One side can be faced off and cleaned up before you put it in the jig, though (make sure that jig is pretty precise if you attempt that).
Ken,
Two of the four are spoken for, and the third is up in the air right now. After I finish and plate everything, I'll post here or contact you.
