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 […]

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 […]

Using OnShape to create etching patterns in InkScape

I’ve been experimenting with OnShape sheet metal models to produce patterns for etching parts. Being designed for ordinary bending processes, OnShape is not directly applicable, but I think it is close enough for my purposes. Here are the sheet metal model parameters that I have found work in OnShape to produce drawings that match the […]

OnShape and etched fold lines

Due to flooding, progress on real modelling has halted, and I’ve had to move into the virtual realm. This is okay, as there is loads of drawing work yet to do on 622. I speculated a couple of months ago that some careful manipulation of OnShape’s new Sheet Metal Model feature might yield a good […]

Sweet anticipation

It doesn’t matter how many times I order printed parts from Shapeways, it still feels like magic. The patterns for 622’s wheels existed only in my mind until I drew them in OnShape. Now in a few days, I will open a package, and they will spill out into my hand – no longer mere […]

Mobile Modelling

It’s hard to believe the iPhone is only a decade old, when the world has changed so much. Today, I had to wait in a parking lot for a few minutes, and as I was thinking about the look of 622’s truck wheels, and how they don’t quite match the photo, I thought I’d see […]

Pilot wheel drawing

I’m planning a two millimetre axle for the 30-inch pilot wheels. The wheel hub comes out pretty heavy with 3/4 mm walls, but I daren’t go finer. Indeed, I will have to test to see if I can even turn such a fine wall.

OnShape Sheet Metal Models

A couple of weeks ago, I noticed a new feature in OnShape: Sheet Metal Models. It almost sucked me into a rabbit hole, but my objective was drawing a driver, not experimenting with cool new features. So, I parked it until this evening, which I seem to be spending babysitting the Cricut as it makes […]

Driver drawing

As I’m planning to print patterns for the wheels, I could no longer be satisfied with blank discs representing the wheels, even in OnShape. They’re a bit of a challenging part to draw, but I think I’ve captured the look of this photo from the Parry Sound Public Library. Possibly the hub is too small – […]

Flatcar weight plan

The thing that makes flatcars challenging is surely how to make them heavy enough to stay on the track when they are empty. If it makes you feel any better, it looks like real railroads had the same problem back in the wood car era. They appear to have blocked empty flats near the back […]