Coupling Rod Bearings
Back on the 10th of July we provided an update showing the process involved in remetalling the coupling rod bearings. At this stage with the Leading, Trailing and Driven bearing position bearings being remetalled machining as started on these bearing to bring them to the correct dimensions and surface finish.
Luckily some of our volunteers have very well equipped home machine shops which mean this work can continue safely in the background.
Machining of the coupling rods involves setting the bearing up in the lathe.
An indicator is used to ensure the bearing is setup concentric. Then a face is surface cut to establish a datum point.
The bearing internal diameter is then bored out to suit the crank pin outside diameter + the requires running clearance 0.015” (as per the Victorian Railways practice cards). Once this is complete the opposite face is then machined so that the bearing length is correct without any excess lateral clearances. In this case the bearing ends have been built up with whitemetal to correct for wear to the bearing.
The finished product is then ready for oil passage ways to be drilled. Once this is done the bearing can be pressed back into the coupling rod, ready for reassembly onto the engine.
Thanks for your ongoing support, we look forward to resuming work at Newport on K163 when it is safe to do so. In the meantime any contributions would be greatly appreciated to keep this project on track.