Valve gear – a complex OnShape part

The valve gear for #622 will be printed as a single part.  As with most of the parts, the original drawing needed to be redone. The first time around, I thought I was very clever by using a minimum of sketches.  I chose parts of the sketches to extrude to different depths, but hard-coded the extrusions. This time I think I’m even more cunning: rather … Continue reading Valve gear – a complex OnShape part

Redesigned crossheads refine OnShape technique

To be honest, I don’t know if I would have this much patience if the real workshop were not still out of commission.  The sheet metal design for the crosshead guides and crossheads took several days (well hours, as I don’t spend whole days on this stuff!) due to a disagreement between OnShape and me about how some sheet metal models should work. We’ve finally … Continue reading Redesigned crossheads refine OnShape technique

Sheet metal construction fixtures

When I built #10, one of the innovative and useful ideas was to create both running boards out of a single large piece of brass.  This helped me get the boiler level relative to the running boards, and since Pembroke is not an incline railway, a level boiler is desirable. I’ve planned the same approach with the virtual model of #622.  Interestingly, using the Finish … Continue reading Sheet metal construction fixtures

Engine truck design – the murk beneath

When you model something that has been gone for over a hundred years, you get used to squinting at photographs and trying to imagine a design that might present similar patterns of dark and darker.  In the case of the engine truck, which is missing from the erection drawing for 622, I found a drawing online that explained the shapes beneath the cylinders.  I used … Continue reading Engine truck design – the murk beneath