Progress with the Axle Boxes
Progress to February 2014
After our excellent progress over the Christmas/New Year period we were back at work at Boston Lodge over the first weekend in February.
The primary focus of the weekend was to get the axle boxes into a state whereby they are ready to have the newly cast brasses fitted. The original design for the axle boxes is to have the journal bearing and thrust face bearing in the same casting. This has a major disadvantage; because the locomotive has a long fixed wheelbase, the thrust face wears much faster than the journal bearing. Therefore the journal bearing would require replacing before it is worn out. In China, it appears that in order to prevent the thrust faces bearings from wearing, they were modified to be constructed out of steel. This is obviously counter productive because instead of the thrust face wearing, the back of all the wheels are now worn and require remedial work. We are modifying the design further, primarily to reverse the addition of the Chinese steel thrust faces but also to allow the new thrust faces to be changed without the need to change the journal bearing at the same time. This has required some of the cast steel axle boxes to be built up with weld and re-machined back to their original shape. In this task, Dave and Chris worked all weekend carefully setting up each axlebox in turn on a rotary table milling machine and machining back the built up weld. Many thanks to them for their help!
Other work this weekend included putting another coat of paint on the frames and other minor jobs that needed tidying up.
Hopefully by the next working party, the new axles will have started being machined. Watch this space!
Chris and Dave set up the axleboxes to re-machine the recess in which the thrust face is located. - Andrew Nelms 01/02/2014
The re-machined axleboxes lined up in the C2 shed. - Chris Veitch 02/02/2014
Another view of the re-machined axle boxes next to the wheels, still waiting for the new axles and tyres to be fitted. - Andrew Nelms 02/02/2014
Hot of the press (well the milling machine anyway). The first box to be re-machined. The recess for locating the thrust face can clearly be seen. - Chris Veitch 01/02/2014
Another coat of paint on the underside of the frames. This second coat is in blue to get some contrast with the black so we can see where we've already painted. The final coat will of course be black. - Andrew Nelms 02/02/2014