Ok, so I have made some signals before, but these have always been 'modern' ones with tubular posts. Clare has lots of upper quadrant signals but most of these were just replacement of the old GER lower quadrant signals and reused the existing tapered timber posts. These posts are available from various suppliers in white metal but I've always had a nightmare reliably sticking on the various fittings and soldering white metal is for those more skilled than me.

I decided to see if I could draw up and 3D print a post with most of the fittings already attached. I've modeled this in a 3D CAD package which allows 'parametric modelling' and assemblies so that I can easily change the height of the post or add additional lamps and fittings for additional arms. I was concerned about the strength and stability of the resin, while I can get away with a slightly bent post but didn't want anything that the S&T department would worry about. I decided to try adding a 1mm hole in the model vertically down the post into which a length of wire could be inserted after printing but before the final curing. I tested this out on a test print and the result was surprisingly strong. I can deflect the post by about 20mm in any direction (with a reasonable force) and it will spring back to the vertical.

The wire is extended through a brass base and then onto a tube which can be used to mount the signal in the baseboard. The brass base gives something sold to solder the bottom of the ladder to.

The brass fittings are from Model Signal Engineering. The 3D print has a 1mm hole where the arm pivots which is sleeved with a short length of thin brass tube. The balance weight arm is pivoted on a length of .45 nickel silver wire which passes through some holes in the 3D printed bracket.

Because of the wire passing through the post I printed the finials separately. The original GER spikes seem to have been replace by simpler cabs by the 1950's. ( and my first attempt at modelling them make them look a bit to fat.

I've used a modified version of my 3D printed servo mount for uncoupling magnets to drive the operating wire. The signal wire has a tiny magnet on the end which is attracted to a magnet on the plunger on the servo mount. The result means that I can detach the signal from the board and the linkage will re-establish itself when put back. Currently the servo is being driven by a MERG 'Pocket Money Kit' which means that the operation isn't quite as smooth as it might be. I'll replace this with a MERG Sema4 (the same board as the Servo4 but with different firmware which allows bouncing) at a later date.

I've put a short clip on Youtube.

https://www.youtube.com/watch?v=FL25V_41VDE

This ~120mm tall signal is getting near the limit of what my Anycubic photo can print. I should be able to do the starter and slotted distant signal the same way.

David