Recently there has been much work but not a lot to show for it. I returned to the chassis in an attempt to get that running before carrying on with the body and cab. much of the time has been spent fine tuning the fit of the gearbox so that it doesn’t rub and getting the rear axle to pass through the gearbox and be a tight fit but still be removable for painting etc. This is more interesting because of the wheels being fixed to the axle stubs and the gearbox having ball races which want to grab onto the axle.

I also had a rather frustrating time trying to make a pin for the outer end of the return crank which attaches the eccentric rod. I had tapped the small end of the return crank 12ba and the plan was to make a small shouldered pin threaded 12BA with a large flat head that I could attach an etched cover to.

This gives an idea of the desired pin with the etched covers below

The observant amongst you will note that the threads look very undernourished on the pin. This was possibly my fifth or sixth attempt and I kept putting it down to my having the pin too thin, too thick etc. as each time the thread came out too small for 12BA. Eventually I examined my 12ba die under some magnification and realised that one of the three cutting edges is out of line with the rest and is what I am sure was causing all the failures.

I can’t actually recall if I have used the 12BA die at all (I use the 12 BA tap set regularly but generally for fitting bought hardware) and if I have I would have only used it on brass or nickel so I very much doubt that I have deformed it. It has been consigned to the bin and a new one ordered from Chronos. in the meantime I will probably modify a a couple of 12BA set screws to get on with the job but when the new die arrives I will have to make another to prove once and for all that it’s not something that I am doing wrong.