Monday, 28 September 2015

Terrier Progress - some gears

I have now received a new set of wheels of the correct diameter (8mm) and I have given them a quick spray of primer (one set black for my second Terrier and this set grey for painting green and black for my Southern livery Terrier).

The next job on the chassis was to drill out the 0.3mm holes for fitting the brakes and the 'Simpson Spring' axle pickup wipers. Two of the brake support holes require drilling into the side of a glass fibre PCB spacer. Typically, my drill bit broke doing the last hole. I had to unsolder the spacer, remove the broken drill bit, put the chassis back into the jig and resolder the spacer. Then I had to redrill the holes with a fresh drill bit.

Now I was ready to start fitting the gears to the accurately turned 'muffs' and fit them in the chassis temporarily with some long pieces of axle steel. The muffs needed a little triming to length, and drilling and reaming to give a tight push fit on the axle steel. I also drilled across the centres of the muffs to let air escape and to insert superglue if required when the wheels are finally fitted. The gears were deburred with some fine emery paper and then fitted to the chassis. They would not turn. The main worm gear was fouling the axle muff. I took the axle muff, inserted a length of axle steel and mounted it in the jaws of a mini-drill. I then used a good small file to reprofile the muff to give room for the worm gear to rotate. Once refitted, everything turned freely. The turned muffs do appear to be better than the old ones. I might return to the '09 Diesel Shunter' I started building previously that suffered from non-concentric gears, to see if they improve things.

Well, that was it for the evening, the broken drill bit and gear-muff interference problems meant I did not have time to fit any wheels. Hopefully next time ...

Monday, 7 September 2015

Fiddling with the Fiddle Yard

Not much progress to report on my Freshwater layout itself, as various projects have stalled for one reason or another. However, with some exhibition bookings a couple of months away, I had to make some progress somewhere. I turned to the fiddle yard.

Originally, in the rush to complete the layout for the 2mm Scale Association Golden Jubilee Challenge, I just roughly laid a few 60 foot track panels on double sided sticky tape across the fiddle yard and joined them up electrically. This single line has sufficed so far, but it did mean a passenger train had to be taken off or put back on again when required.

Five years later, and the sticky tape is not as sticky as it once was. Track panels started coming loose. I decided to take the opportunity to add a point while I was relaying the track. This would pretty much double the capacity of the fiddle yard, although slightly reducing the train length. So I built my very first EasiTrac point, with a 1:6 crossing so it would be as short as practical. The point, and track panels, were glued down with EasiTrac glue this time.

I laid the plain track straight, at the diverging angle from the crossing, for several reasons:
  1. There was room to do so
  2. it is easier to put stock on straight track than on curved track
  3. it is easier to put stock on when another track is not too close to it

I decided on a low-tech approach to point operation, similar to that used on my previous layout 'Brunswick', in complete contrast with the Merg CBus controlled servos and under-baseboard tie-bars used on the layout itself.

A piece of glass fibre PCB is used as a tie-bar, and an electrical toggle switch, mounted on a bracket from the DIY superstore, provides both the mechanical movement and the electrical switching of the frog. The switch is connected to the tie-bar with some Plastruct pieces (the outer tube section being glued to the baseboard with a smaller rod section free to move back and forth inside) and some pieces of wire guitar string.