Tuesday, February 26, 2013
A simpler chassis for a model railway engine, you couldn't hope to find. Only 4 wheels, a short wheelbase and since the whole thing is hidden under the body, none of that fiddly brake gear or indeed, any detail whatsoever.
The main part folds up from flat. Simply solder the bent down spacers to produce a nice strong box.
Next the bearings are fitted. Both the chassis holes and bearings need to be reamed out a bit to get them in the sideframes with an axle through the middle. Since I'm not that well equipped for O gauge, I had to use one of the axles I intended to fit later to line everything up. I really need to pick up a spare so it can be covered in flux and muck. Never mind, a quick wipe with WD40 will hopefully prevent problems.
The gears are from London Road Models and massive chunky beasts. The gearbox allows for a couple of mm adjustment but this wasn't needed. It doesn't have it's own axle bearings, just slipping over those already in place. Best design feature of the whole thing is the inclusion of a couple of slots in the spacer to allow a screwdriver to get at the grub screws to release the motor. If only other kit designers were so thoughtful.
At the back, an L-shaped bit of wire is soldered in so it touches the centre of the axle. Then the bearings are filed so the holes are oval. That way the axle and pivot around the rod providing 3-point compensation. Clever eh?
While possibly not required for a short wheelbase 7mm loco, it's not a bad idea as the squareness of the chassis isn't so vital.
Next - to try it on the layout.