Baldwin 2-8-0 cab attachment screw size

[nemodelworks]

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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Have you tried taking it to your local hardware store?  My hardware store has a really neat tool that identifies but and screw sizes.

[Len]

Those are both thread cutting screws, not machine screws. There was no tapping of the holes they go into involved. In soft material, I find drilling a hole slightly larger than the diameter of the shank usually works. You want roudhly 1/2 of the thread to cut into whatever material you use, with the open space between the material and shank for the material to expand into as the screw is driven home.

Len