As you recall, the staging yard is on a wide window sill, and that means there is no room for Bullfrog or other switch machines below the roadbed. Because the room provides a number of functions in our house, we want to be able to make the staging yard look like a clean window sill, which means there is no place for a ground throw above the window sill either (although perhaps if they were painted white, they wouldn’t be too objectionable.
I decided to think about flick switches, similar to Peco and Micro-Engineering. Actually, I’ve only operated with Peco in N Scale, but I do find the flick switches are very convenient and intuitive. Of course, being on the cheap side, I’m not about to go out and buy a bunch of turnouts and convert them to Proto:87. So, I spent a few days thinking about how I might achieve an over-center spring of my own.
The other change I’m making for the staging yard points, is in the switch rod. There is no need to use the 3D printed parts as on the visible layout. So, I’m going to use PC board throw bars. Others have found that the joint between the PC board and the rail is prone to failure, and so, I devised a method using pins. The points are soldered only to the pins, which means they can rotate freely.
Tonight, I spent about three hours putting a prototype example together. It worked superbly on the first try!
Some things I learned:
- You need to be careful to get the second headblock perpendicular to the track. Otherwise, you’re putting pressure on the point-throwbar joint.
- The nub on the throwbar that interacts with the spring is .020″ brass wire.
- The spring was formed by pressing it around a piece of .064″ wire. It is not especially precise. It is .008″ phosphor bronze sheet.
- As I’m doing six turnouts, it’s going to be worthwhile to come up with a fixture for making throwbars and springs.
- It might be easiest to assemble the headblocks and throwbar on a piece of shim stock before having to worry about rail.
- The pin idea works well, but they’re a pain to solder without soldering to the PC board as well. On one side, I filed away the copper at the pivot point, and that simplified matters substantially.
- The pins want to turn sideways. I shall consider drilling through the point to improve this behaviour.
- I tried simply bending the points, rather than providing a hinge at the heel. While this worked, I find it makes forming the wing rails even more challenging. I think I will go back to hinging the heel (in which case, do I still need to pins?