Kadee Couplers on Bachmann

[nachoman]

My first suggestion, for both problems, is to see if you can somehow get a kadee #5 coupler box to fit. I am not familiar with this particular model, so I don't know how feasible that is.

If you have to use the original box, you can fix the thread problem by cementing a small plug of styrene (like a bit from a sprue) into the hole, cutting it flush, and then re-drilling it and tapping it for a 2-56 screw. To solve the space problem, you can try sanding the shank of the coupler thinner, or making the box a little bit wider. To make the box wider, I would first sand the inside surface of the lid with 400 grit sandpaper (or finer) to make sure it is absolutely smooth. You can build up the edges of the box with thin strips of styrene, and then assemble as usual.