If you’re thinking of following along and using my method to build your own turntable, may I recommend that you make friends with someone with a lathe instead. I’m sure the whole thing is much easier if you have decent tools. Making the bridge itself is probably a doddle if you have a lathe.
I especially like Coquihalla Man’s approach to making the bridge. I’m not sure, but the timing of CM’s posts about his turntable and engine house at Brookmere are certainly suspicious; thanks CM if you’re helping me on purpose. Of course, he is a cabinet maker by trade, and creating accurate and precise pieces of wood is what he does, and knowing now what I do, I should have gone to him for help in the first place!
I am not a cabinet maker, but more of a bodger. Making things that align despite themselves is what I do. Slowly. Anyway, for posterity, here is how I have created the core for the turntable bridge. It consists of a U-shaped centre, which is narrow and short enough to be hidden completely beneath the table. The two sides have platforms formed in the ends to support the rails and feed power. All parts are .025″ brass.
The U-shaped centre has four 2-56 nuts soldered to it, which bolt it against the turntable base. To solder the sides on, I bolted the centre down, and supported the ends of the sides so that the platforms are exactly the height of a tie above the pit wall. I used my resistance soldering unit to sweat solder the sides on.
I need to create some cross members to keep the bridge straight. There is more soldering to go, and so, at least for the ends, these will have to be PC Board.