Thursday, 6 October 2016

Missenden Autumn 2016 - down to work...

So after setting the scene, what did I manage to achieve over the weekend on my Buckjumper?

I'd last done a major piece of work on the locomotive at the Missenden weekend in spring 2015. Since then I've done a little bit of tidying up on the workbench at home but nothing major. The stage the locomotive had reached was that I constructed the shorted out wheels for the split frame chassis, put the chassis together, quartered the wheels, and made sure it rolled freely as an unpowered chassis. I had put together a High Level gearbox, reduced in width thanks to the inspiration of Steve Duckworth in encouraging me to take a piercing saw to such a lovely piece of engineering. It now sat cleanly in the insulated centre section of the driving axle.

So the first thing to do this Missenden was to see if all of my efforts had been in vain in my first attempt at a split chassis. I cut a couple of lengths of electrical wire and threaded one end through the terminals on the motor, then soldered the other end to either side of one of the PCB spacers in the chassis.

Connecting an ordinary 12 volt controller borrowed from John Gowers to my short 6 inch length of P4 test track I gently turned the power knob up and to my amazement the motor ran. It's not conclusive proof that split chassis work for me, as I still see a number of problems with them that need to be solved, but it certainly surprised me that it worked first time. Apparently I was very happy for the rest of Friday evening and wouldn't stop talking about it, according to the other members of the group.

This shows the chassis sitting on the length of track at the top of my workbench. As I said, the wiring is just a lash up and the more permanent arrangement will be longer wires to slip the motor inside the boiler and also the inclusion of a DCC chip.

The next stage on the chassis was to fit the brake rigging.

As the steel tyred wheels were already in place along with the motor and gearbox, and although I could have dropped them out I needed them in place to judge where the brake blocks were going to go, I decided to forego my usual technique of soldering and resort to superglue. I had opened out the holes in the brake shoes and in the brake rigging to 0.45 mm to be able to use matching nickel silver wire to form the brake rigging from one side of the chassis to the other.

This whole process took quite some time for two reasons. Firstly the pre-etched shape of the brake shoes didn't match the profile of the tyres of the wheels, so there was quite a lot of filing required to make sure that when the brake shoes were fitted to the upper mounting wires they were located in the correct place. The second element was that because the brake rigging came in separate sections I wanted to make sure that each section was correct correctly located and soundly fixed in place before moving onto the next. So it was a case of glue one section, do something else/go and visit another group/have a cup of coffee whilst the glue dried and then return to the next.

This picture is of the chassis with almost all the brake rigging in place, apart from the final length. This turned out to be the most problematic because the holes at the end of the rigging were over etched and in actual fact were not holes but merely cup-shaped stubs. This meant there was a little bit of swearing and much bodging with lace pins (thanks to James Dickie for the loan thereof) to get it into place whilst the glue dried. It wasn't entirely successful as when I started working on the locomotive on Sunday evening after returning home this section fell off due to the brittleness of the superglue, so I resorted to a slightly chunkier quantity of 24-hour epoxy resin to put this particular piece back in place.

With the chassis done as far as I could, it was onto the body but that is for next time…


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