I bought a Baldwin 2-8-0 with the intent of designing a cab that better represents a New Haven F-5. The plan is to 3D print the cab using a resin printer.

I was able to disassemble the model by removing the screw that attaches the drawbar to the locomotive, then removing the shell. After removing the shell I could remove the cab by removing the screw under the top of the boiler that passes through the weight inside the  cab that screws into threads tapped into a post that is molded to the top of the cab.

I realized I will need to design the new cab so it can be mounted to the boiler using the same screw and tapped threads in a post. To  tap threads in a printed I need to purchase a tap that matches the size and threads used on the screw.

I attempted to get the screw size by calling Bachmann customer service. I was told they couldn't provide the information and that I should try asking in the forums, so here I am asking. Does anyone know the size of the screw that's used to attach the cab to the boiler of the HO Baldwin 2-8-0?

I've attached a photo showing the larger screw that I removed to remove the shell from the chassis, and the smaller screw that attaches the cab to the boiler.

If I can't get the screw size of the smaller screw I may be forced to purchase a similar sized screw of a known size and a tap to match so I can cut threads in a printed post.

Thanks for any help.

Mike Redden
https://nemodelworks.com
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