Now that I almost have a functioning locomotive again, I’m eager to get back to operations. As I had to get the 3D printer out to create a new steam dome after the first got chipped after its tungsten weight propelled it at the floor, I decided to try out a plan for an improved turnout control that has been rattling around my head.
The original design called for an awkward rectangular hole in the fascia. I had the full set printed at Shapeways, but stalled out installing the levers while worrying the second hole into shape. Then over the years since 622 has been on the workbench, the only one installed got knocked and broken. So, clearly they would need redesign and reprinting anyway.
The new design protrudes a little further, but requires only a 5/8” round hole in the fascia. I put together a prototype to test the installation process, as some of the spaces are awkward to reach. I think I will be able to complete almost the whole installation from the front, only reaching the occasional finger behind the fascia.
Sadly, the Mark II design requires a little more strength than the water washable resin can muster. That stuff is good for detail, but a little brittle for engineering work. I will be ordering some tougher resin to print the next version.
One interesting aspect of the Mark II design is that I printed the threads for the two screws. Although tight, they worked well enough to drive the 4-40 screws in, saving me from tapping the holes.