622: Backheads are harder to draft than make

It’s generally invisible except through the windows. So I don’t want to spend too much time on the cab interior and specifically the backhead. A modeller’s sketch is sufficient, I think. If I recall, the backhead for #10 took an enjoyable day of modelling. It was styrene plus a few pieces of lost wax jewelry representing […]

622’s pilot and the power of parametric CAD

I just finished drawing 622’s pilot. Actually, it is 623’s pilot as I don’t have any photograph showing 622 after she lost her link and pin. I think it’s a pretty good match to the photo. Perhaps the angle needs to be a little more acute. But here’s the thing: five minutes ago, it looked […]

Boiler fittings for 622

This week has seen me drawing the domes, stack and smokebox front for 622. These will all be 3D printed to start; depending on how they turn out, I will either use them as they are and fill them with lead, or cast them from Cerro-bend after cleaning up the castings. Again, OnShape amazed me […]

Drawing 622’s Stephenson gear

I just finished drawing up the valve gear for 622 in OnShape. This is certainly the most complex part I’ve drawn yet in the tool, and the idea is to have it 3D printed as a single piece. Sadly that means it won’t work, but in the interest of getting the locomotive running, I’m going […]

Crazy plan for 622’s crosshead guides

Compared to #10, the crosshead and guides on #622 are going to be a bit of a nightmare. First of all, they follow the raised pattern, which is going to make them difficult to locate vertically. Secondly, they are not plain bars, but are shaped to provide strength where the thrust from the connecting rod is […]

622 virtually roughed in

I’m starting to think seriously about the drive train for 622. On #10, I built my own gear box, which enabled me to model the full backhead and floor of the cab. That’s all very nice when you take the roof off, but most of the time you can’t see it. For 622, I’m considering […]

622 suffers do-overs in CAD too

If you’ve been reading my blog for any time at all, you know that I throw out about half the things I make. The first version is never good enough, but it does teach me how to make one that is. So, it should come as no surprise that I just deleted almost the whole CAD model […]

Getting sources organized for 622

For my drawing efforts thus far, I’ve been considering the erecting card and the associated specification for the locomotive as gospel. I mean, these were the resources that the boys at Baldwin would have used to put 622 and 621 together, and so they should be right. Unfortunately, unexpectedly, inexplicably, they don’t agree! The drawing […]

Figuring out OnShape connectors

After watching the tutorial again, and sinking another night into learning OnShape, I’m not only in danger of dying prematurely because my body didn’t break down enough sugars and triglycerides, but I’m also in danger of becoming effective at creating Assemblies. Perhaps I should explain for those SketchUp users out there. OnShape (and FreeCad) work on the basis […]

622 drawing progresses in OnShape

I’m starting to get the hang of parameterized CAD with OnShape. Tonight, I managed to get a pretty good sketch of the locomotive frame, and extruded it to make the outside layers. I also discovered a handy feature called a variable, which enables you to label a dimension, such as the standard thickness of metal, […]