5.1 Bogie frames

Well at long last I got started. My previous projects all lasted several years, so be patient and follow along. Admittedly my AD60 still needs some work but I'll work on the Fairlie when I can't work on the AD60.

The number in brackets in the text, like [2], refer to the numbered instructions in the restructured manual for the power bogie

Unpacking the etch sheet. Oh boy at last I can start.

Studying the etch.

Luckily most, but not all parts are numbered.

The first cut! The project now really has started!

[1] After some cutting the first four parts lay on my desk. The manual is not very specific about it but each frame plate is built up from one full thickness plate and one half etched plate. I could find no particular detail justifying an etched wrapper, like nuts or rivets, so I must assume that the layering of the frame  plates is simply for thickness.

The half-etched frame plates curl a little. The nickel silver sheet is produced by rolling. The stresses in the sheet compensate each other and the full sheet lies flat. If you etch one half away the other half no longer get the counter pressure and tends to curl.

The parts left of the frame's components are parts that came loose with the cutting out of the frame. These will be stored in a sorting box for later use.

The curling is easily corrected by gently rolling the frame with a tube (be it brass or aluminium) until dead flat.

[2] Soldering the two plates together. Although I found no obvious reason for handedness I made sure I had a left and a right hand frame.

[4] The mid frame spacer (8).

The part on the right was again one that come off as a by-effect and was stored for later

The spacer was checked for squareness. The light passing from behind between the beam and the spacer is a very harsh judge.

During soldering, and just in time, I realised the intention of instruction [6]: "do not forget to bend out the two tabs for mounting the pickups".  Errrrm, okay

Done. After cleaning.

The axles of the Fairlie are designed to have sprung bearings. The up and down movement of the bearing is minimal, no more than half a millimetre either side of horizontal but it has two effects.

• it keeps all the wheels on the track for power collection.
• it makes the whole loco ride smoothly across inequalities in the track. Shock loads like a step from a rail joint, which without springs would be a sudden jerky upward movement, become smoothed out oscillations as the initial shock is taken by the spring deflecting and any movement to the body is passed on slowly and with the jerkiness taken out.

The wire touched neither the bearing nor the axle. Now what?

The instructions were not clear on how the springing of the bearings was to be arranged. I contacted EDM Models and Paul Martin was commendably supportive and provided me a drawing and the following instructions

• Solder a point of contact wire (0.9 mm) to the top of the bearing. This is important as
  • it spaces the bearing down,
  • extends the bearing inwards slightly so as to be under the spring wire and
  • gives a single point of contact with the spring.
• Reduce the angle of the springs hangers and the wire will be nearer the frames.
• Use the supplied steel wire for springs and not the phosphor bronze wire (as per the instruction on the CD).
• Bend the ends so it can't escape from the holes.
  Don't solder the spring wire in at all. The wire needs to be loose in the spring hangers so that as the spring deflects the wire can slide in the hangers on both sides. If it didn't because one end was fixed the wire would have to slide double the distance on the free end and also have to slide across the contact point on the bearing.

Note: the instructions on the CD mention phosphor bronze wire for springing. Since the release of the kit some things have changed. This is one of them. Phosphor bronze loses its bounce so steel is a better springy wire.

DO NOT CUT this wire with a delicate flush cutter for brass. Ensure you use a cutter that can handle steel.

Getting the 0.9mm steel wire to size was a bit of a fiddle. To make things easier I made a few passes with my three square file on the top of the bearing. The steel wire will settle in the groove and you can press it down with the point of a knife blade to hold it in postion while soldering.

I made two choices

• the slit on the side of the bearing is not exactly in the middle. I opted to put the thick side of the bearing on the outside of the frame. The instruction do not mention it, but it logical as the bearing's surface comes flush with the outside surface the frame
• I established the length of the bearing top wire to be 2.5mm. If it is too long it will interfere with the gearbox later. If it is too short the spring wire will slide off. With 2.5 mm it may still be too long but I'll take care of that later. I can always file it further down.

This is what Paul showed me to do. Once you have seen it, it is easy.

The grooved bearing and 2.5 mm length of steel wire cut, filed.....

...and soldered.

Up!

And down!

And down!

Good, three more to go for this bogie and for more for the second bogie. I all did them in one stride, being at it anyway.

[12] Next job is on the rear frame stretcher. I chose the tapered version because I want to model Merddin Emrys as I saw it in 2009 and 2011.

After soldering I was proud because

• I made this mini-part of less than 6mm length out of three pieces
• soldered them neatly together with 188C solder
• without unsoldering one part when soldering the other
• with a minimum residu of solder to be removed
• and most important without stress and without sorching bodily parts.

[15] Cutting out the motion brackets

A few thing of note:.

• if you want to model the 16.5mm version you MUST choose the wide brackets now (no 40)
• if you want to model the lubricators remember they are on the driver's side (right side facing Porthmadog). So the bogies are handed from this moment if you do so
• Also observe that David Lloyd George has two lubricators per bracket (four in total) and Merddin Emrys only one per bracket which faces inwards (towards the cab).

I have no idea why I should drill holes. I drilled them anyway at 0.5 mm

David Lloyd George passing Boston Lodge Works with a train to Blaenau showing four lubricators, 13 June 2009 16:06

Less than fifteen minutes later Merddin Emrys passed the same location heading for Porthmadog. Only two lubricators are evident. I read by the way that four lubricators is the new standard. Merddin Emrys is currently (2016) disassembled for overhaul, so it possible that ME will reappear with four lubricators.

Using the 0.6mm brass pins to position the brackets is an ingenuous invention. It places the bracket super accurately and it releases one hand to do other necessary things.

I first tack soldered the bracket in the middle, top and and bottom (in that order). Then I withdrew the pins to the point where they could be snipped off with a minimum of waste and ond then I gave it a complete pass of the soldering iron.

One frame completed