3.5 inch gauge Derby 4F

Hello there,

My Dad got the plans and collected the Don Young articles back in 1975 for building a Derby 4F. It was always a back burner job, he always justified having a machine workshop based on the loco he was building. Unfortunately, life managed to get in the way, and the loco sadly still hasn't been built. However, he has completed the boiler, as well as a few other parts.

In the last few years, I've managed to get my Dad to dig out the plans with the idea of drawing them up in 3D software (got most of the way through with Solidworks, just started again in Autodesk Fusion 360).

As an experiment in 4th axis CNC machining, I made the 4Fs drive axle from a piece of solid stock. If you search for "3.5 inch Gauge Derby 4F" on youtube, the axle being machined is my video. The video of an engine running, I believe belongs to someone on this forum.

I can't seem to find in the drawings how the lubricator is connected to anything to make it actually pump oil, anyone have any idea?

I'm actually planning on getting the loco completed now, for now just going to concentrate on getting the valve gear working on air.

Thanks if anyone can help,

Tony.

I've uploaded a possible solution here, (let me know if there's a better article)

Brilliant, thank you. I think I actually have that article, but I have yet to delve that deep into it. So it just adds on to the eccentric strap. I was thinking of adding another eccentric to the front axle, if I can fit it in.