June 2007: I was unhappy with the worm gearbox. With just the motor and worm fitted (no gears) it was very rough compared to when the motor was out of the gearbox. Flexing the gearbox did allow the motor to speed up, but I just could not make it stay like that. Eventually I realised the gearbox had folded up not square. I removed the bearing from the far end and the worm rod was naturally hard against the side of the mounting hole rather than in the middle. I took the gearbox apart at the fold lines, filed the edges square and soldered it back together square, so that the worm rod was central to the bearing mounting hole, and when the bearing was added, the motor still ran smoothly and very, very slowly.

Now I think I stand a chance of making it work with some gears in position too. However, I want to blacken the chassis first.

June 2008: It is over a year since my last posting. I had been making excuses, such as pressure of work commitments, life, looking for a good way of blackening the chassis, etc, but mostly it was down to being disappointed in how the chassis was running. Anyway, Friday 6th June, I got all the bits out of the box again. The rusting tube the worm is mounted on was cleaned up with emery and oiled, and found to be running smoothly in the chassis with just the worm gear on its idler shaft.

Adding the next idler gear messed things up though. It looks like the worm gear is slightly non-concentric on its shaft. The bearings have been opened up to give a little play, but adding the next gear took away thay play. So, some more careful opening up of the bearings eventually resulted in free running of the gears.

By now, the stub axles used by the idler shaft muffs were quite a loose fit, and kept dropping out. It was time to glue them in place. For the second shaft, with the breather hole drilled in it, this was a simple matter of applying some super glue into the hole on the end of a pin. The worm gear shaft is trickier, because there is no room for such a hole. I inserted a small piece of plastic rod to ensure the two stub axles can never meet in the middle. Then I tried adding some glue into the ######, putting it into position, then inserting the stub axles through the bearings. First I tried superglue, then I tried Uhu. No real success with either, except that I managed not to glue the ###### to the chassis. However, the stub axles are now a tighter fit, and might stay put.

The rear wheels were fitted next. The ###### had to be reamed out quite a lot, but still retaining a tight grip on the half axles. Everything was still nice and smooth. Adding the centre wheels locked the whole chassis up though. The gear was hitting the solder and folded tab of the spacer fitted above it. The solder, and some of the tab was carefully filed/chiselled away until there was clearance. The same was done for the front wheels, but eventually, on Friday 13th, all wheels were turning sweetly, and very slowly, under motor power.

The chassis had been blackened using a CD marker pen. It needs touching up after all the fettling, but it is a quick, easy way to do it.