GCR Class 5A Crank Pins and Coupling Rods

Another good session at the bench on Saturday saw the wheels blackened and the Derek Mundy crankpins installed. I have to confess that I am not keen on them. I am not that comfortable with drilling such big holes in the Slaters wheels with the resulting chances of something going wrong.
I enlarged the holes with the pillar drill and I also used the pillar drill to push home the crank pins to keep them vertical and despite that one of them wasn’t in square and needed a little tweak.

Derek Mundy Crank Pins

Next up was the coupling and connecting rods, there is a diagram in the instructions on how to cut the coupling rod layers to allow them to articulate on the crankpin. Not knowing any better or having enough confidence to do it any differently that’s how I did mine. Sometime later, Steph Dale went to some trouble to post on Western Thunder a “how to” on cutting the rods to show me how to make them articulate as they should.
Having stored this up for a rainy day I adjusted the cuts and made use of a couple of the spare part rods supplied to make them articulate behind the middle crank pin as they do on the prototype.

There is an etched hole in the outer layer (presumably for a dummy pin) I used this to mark up where to drill the rear layer 6mm. Once all the layers were soldered together and cleaned up, I tapped the hole in the back layer 14ba. Then I threaded some .9mm nickel rod 14ba and made a nut from tube files to a hexagon. Once soldered to the threaded rod I was able to use a 16ba nut spinner to tighten it in to the rods making a nice neat articulated joint.

GCR Class 5A Coupling Rods