Improved engine truck assembly

The first time I assembled the engine truck, it was held together mostly by fervent prayer while the epoxy set. The result was as shaky as my belief in prayer! Perhaps if I were more spiritual, this would be a good strategy for me. The second and third attempts leveraged a new pair of jigs […]

Crankpins installed

I decided to use the quartering jig to hold onto the crankpins while the epoxy holding them in place cured. The theory was that regardless of where the actual holes in the wheels wound up, the vital metric was the distance between wheel centre and the crankpin itself. So, I gave the quartering jig bosses […]

Another way to wreck a driver

You may recall that one of the previous methods to wreck a driver was to drill the hole for the crankpin off-centre. Actually, that didn’t completely wreck the driver: once the spokes had been taken out, it looked salvageable. A short length of steel soldered in the hole and filed flush made it look as […]

Crankpin nuts: a war of attrition

The crankpins leverage M0.6 bolts, with nuts buried in housings inside the back of the wheel. Those nuts are really tiny – 1 mm across the flats, and so, I had always thought I would glue them into the back of the crankpins, rather than risk having them work loose and disappear amongst the ballast. […]

Just two holes!

All I wanted was two holes. Two holes for crankpins 1mm in diameter and the right distance from the centre holes in the quartering jig. It seemed simple enough when I conceived of them. But then, how to get the holes the right distance from the centre? So I made a tiny bushing to fit […]

Ash pan test fit

I couldn’t think of any reason to keep the frame pan underneath the frame now that the bearing guides are in place. So, I took the jewellers saw and hacked it away. Now the frame begins to look like a locomotive frame. Inspired, I ferreted out the 3D printed ash pan and tested it for […]

Stroke to Path could save me hours!

Over a year ago, when I was working on the patterns for 622, I found that drawings imported from OnShape into InkScape consisted of many individual line segments. There had to be a better way, and Craig Townsend has found it. Here for future reference, is a YouTube video that makes it dead easy. Thanks […]

Bearing guides installed

Between the extra-long jig axles and some clamping tabs that I etched into the frame pan, installation of the bearing guides was a walk in the park. I had been a little concerned that the jig axles would be a loose fit on the bearings. As it turned out they were a little snug, and […]

Extra-long jig axles

At least I think they should be called jig axles. These pieces of Aluminum rod are used with the coupling rods to ensure the bearings are exactly the right distance apart. Essentially, I will pass these rods through the bearings, fix the coupling rods to the outsides, and then solder the bearing guides to the […]

Crankpins for 622

This weekend I formed the crankpins. They are turned from brass as I found, when turning the prototype, I couldn’t drill a long 0.6 mm hole in steel. I made them slightly over-length so I can trim them after I see how thick the rods really are. The real trick was the washers. These are […]