Hi
I spent the best part of a day fettling the axle boxes and horns until the axles were a nice easy sliding fit. They need to be a little on the loose side so that the axle can rock a little.
With that done I tried the coupling rods. The first one went on easily but when I tried to fit the other side it was clearly too tight. I managed eventually to get the con rod on but when I tried to rotate the wheels they were clearly binding.
Take the con rods off again for a closer inspection. Join the rods together with a 5/16" pin through one end
Just eye balling the other end it is clear there is something wrong. I turned and drilled and reamed the bushes in the lathe very carefully
I set up a bit of scrap ally bar in the mill, drilled and reamed a 5/16" hole and loctited a 5/16" pin in.
Then using the DRO moved the table exactly 8" and fitted another 5/16" pin
I pressed the bush out of one end on each rod and dropped them over the pins
Once again it can be clearly seen something is wrong.
I pressed out the other 2 bushes and checked each one
The problem is the bushes are eccentric, the worst one by 15 thou!!!
I might be able to solve the problem by rotating the eccentric bushes and aligning them on the jig.
I tried making another bush on a test piece in the lathe and although I centre drilled then drilled the drill could be seen wobbling. The reamer then followed the drill hole. The bush ended up eccentric. I think it would be better where accuracy is required to use a boring bar instead of a drill and reamer
Well at least I have found the problem.
Cheers
Rich