Friday, February 23, 2007

On the footplate


Armed with photos of 08801 I can select the etches to represent the various boxes on the footplate.

On the left side I want a vacuum exhauster, battery box then compressor box nearest the cab.


The battery box should be the short version (lower).

On the right side there's a vacuum exhauster and a battery box.


My loco has different-sized grilles on the vac exhauster (lower). I'm wondering why there's an extra panel with these grilles till I look back at my photos. Sure enough, this version of the vac exhauster sticks out beyond the footplate. Nice one.

At first I tried to solder the parts together, but couldn't work out how to keep the sloping tops in place. Found it easier to join the parts with "Tacky Wax" then add a drop of superglue to secure the joints. The facings were then stuck on with quick-setting Araldite.

The 5 caps on the vacuum exhauster look as though they fold over into place, but when I tried it was a bit tricky to get them all aligned at the same time. So I took the long road, cutting them off and filing to shape. Then starting from the centre I glued them on, separating each with 0.4mm rod. I had to wait for each to set, so I could clear the glue from the inside edges before fixing the next.


I did one flat (left) and the other already made up (right, not yet cleaned up). Not much difference either way, for me. It was very tedious, and on reflection I wish I'd persevered trying to align them on the etch.

Anyway at this point I was renewed by a picture of the finished article on the 2mm Association North East Area group blog

The last thing was to fold up the steps and glue onto the insides of the vacuum exhausters.





Eventually the boxes will be secured onto the footplate and firmly against the body side, but I think I may be better not fixing them until later. In particular I want to get the loco running so I'll know how much lead weight to put inside these boxes.

Wednesday, February 07, 2007

08s on the web


The instructions are now telling me that I have to make some decisions depending on which specific loco I'm modelling, so I need to confess - I haven't decided yet.

My other loco (also an 08) is in 1960's green, so I want something a bit more recent (ie blue). This will allow me to run some of my 80's N-gauge wagons waiting to be converted to 2mm scale.

The instructions give the following points to be researched for a chosen prototype:

1) is there a vacuum exhauster on the right side?
1a) if so, identify side panels
2) is there an air brake compressor cabinet on the left side?
3) bonnet doors - riveted or pressed steel?
4) type of bonnet front grilles, and whether lower cover present
5) position of front and rear marker lights
6) whether ladders around front bonnet (early locos)
7) wooden or pressed cab doors

In short I'll need photographs clearly showing both sides and both ends (preferably taken around the same time) of my chosen loco.

Not being a photographer, I haven't got any locomotive photos of my own, but fortunately these days many people are happy to share their collections on the web.

I'm looking for photos of locos as they were at the time - showing clearly all livery details, and of course the grime that I'll need to represent. So Preservation Society sites don't count. To my mind, these locos don't look right if they're kept too clean.

some useful sites

I found Rail Photo Archive a good place to start. It's the most comprehensive of the ones I know, and you can search for your favoured time, livery or location.

There are also photographs of a large number of locos (and some related stuff - he appears to be an ex-worker at Cardiff Canton depot) on Martin Bray's site. In particular his 08 / 09 gallery includes a photo of many 08's, together with date and place taken, from the 70's onwards.

Graham Turner's Rail Blue site has additional information on many of the photographs, dated around the 70's to early 80's.

Colin Marsden's books are mentioned in the instructions. He also has a website therailwaycentre.com with some technical information.

Mark Shipman has a section on 08s from the 80's onwards.

Comparing these photographs against my Motive Power Pocket Book (1992) suggests that the air brake compressor cabinet is present on the left side for locos with dual (air and vacuum) brakes, but not for those with air brakes only.

Railfaneurope has a gallery of shunter pictures from various contributors, mostly from the 90's onwards.

Dazza has 08s from the 90's onward.

Justin Buckley, Dave Swan and The Bufferstops all have small selections of recent 08 pictures.

Robert McCulloch has some Scottish-based photos.

Colin Birch has 08 and 09 sections, unfortunately not all the photographs are dated.

Andy Small has some nice photographs of 08s at work "in the landscape" but by their nature they're not the best to establish detail.

Locoscene takes some time to browse, but if you know what you're looking for just log in as "guest" then type the loco number in the "find loco" box.

And BR Diesel Web has some downloadable sound clips of 08s in the "shunters" section.

Far from having no photos to model from, now I'm spoilt for choice. Eventually decide to go for 08801 as I found several clear images from the 80's, but also because they were taken around Penzance in Cornwall. I once spent a happy afternoon there around 1971 just watching the trains from behind the wall, thinking grand thoughts about modelling the station. This could be my first small step towards that dream...

Saturday, February 03, 2007

The footplate


First I'll need a jig



This will hold the sideframes, bufferbeams and footplate in place.

Plan view from underneath the footplate.

This shows how, when the bufferbeams and outside frames are soldered on, the gaps will divide the underside into 4 electrically isolated sections.

The underside must also be isolated from the top side, hence the need to file back the PCB from the edge of the bufferbeams.

The instructions say the bufferbeams should be “centralised on the footplate, flush with the top surface, and vertical.


With a steel square clamped to my board and a line drawn perpendicular, to it, I can position the bufferbeam then hold the footplate firmly against it with a cocktail stick while I solder.

The angles are OK, and the isolation gaps all correspond. But it's too long for the jig. I take a bufferbeam off, file the footplate back and solder the bufferbeam back on. Now it fits the jig perfectly, but the sideframes won't fit inside. I file a fraction off the sideframes and rather more from the inside edges of the bufferbeam until it all goes together.

bufferbeam inside edges reduced


Now the footplate fits over the sideframes in the jig.


There's only a small area of footplate between the frame and the isolating gap, so soldering will be tricky. This shows one of the easier corners.


Managed to solder three corners together, but the gap was too close on this one, so I had to slide some solder underneath the frame near the axlebox.

Not sure why the gaps have to be so close to the frames, but at least its done, and with all the sections isolated.

Only needs wheels and a body.

Wednesday, January 31, 2007

Building the bufferbeams

bufferbeams, bufferbeam overlays and thin PCB sheet



The overlays are soldered onto the bufferbeams on one side



and PCB soldered onto the other side then filed to fit.

Using PCB means that the bufferbeam insides are electrically isolated from the beams on the outside.


These gaps ensure that the sideframes can be joined to the ends of the bufferbeams without being electrically connected.

A fraction of the copper coating has been filed from the bottom of the PCB to ensure isolation during a later phase of construction.

Wednesday, January 24, 2007

Building the axle boxes



These are provided ready-spaced, so layers can be built up while still on the fret.

First layer soldered onto the outside frame.


I use solder paint between the layers. With everything aligned, a soldering iron pressed on top of the layer makes the joint firm.


Any excess solder is removed with a glass-fibre brush.

Saturday, January 20, 2007

Getting the motor working


I know the motor runs on its own, and I know the gears turn - now I have to get them working together.

Optimistically I start the motor with all 6 axles in place. Not a flicker. Turn the power up a little... still nothing.

I'll have to take this slowly. Removing the wheel axles leaves just the worm and worm wheel in contact. The motor turns hesitantly in one direction then stops, still nothing in the other direction. With the power on low, I help the motor through the sticky patches by pulling one side of the worm down with pressure from a pair of tweezers. Soon it's turning under its own power. Still not smooth, but a start.


But the other direction is trickier. With the power off I try to turn the worm. It's very stiff in places but I manage to get it round. After about an hour, it's running both ways on its own. I'm hopeful that some "running in" will resolve the stickiness without me having to check the components.



At least when I add the 3 wheel muffs (still on makeshift axles) it all runs reasonably well, but still not smoothly.

Eventually decide to check the worm wheel axle. On close inspection there is some friction between the muff and axle bearing. I take it out, file the end of the muff and
glass-fibre brush the axle bearings. Do this a few times, with improvement each time. Perhaps that was the problem all along.

Some lubricating oil on the worm wheel also helped. As did unscrewing the motor a quarter-turn from its bearing, but now the motor had to be aligned accurately. I would need to take care when securing the motor to the frame spacer underneath.


Using strips of card and paper, I find that the worm wheel turns fastest with 0.4mm support. Stick this onto the spacers with double-sided tape as a temporary measure.

I don't want to add the wheels and coupling rods until I've got the gears moving as well as possible, so meanwhile I'm going to start on the underframe.

Wednesday, January 17, 2007

Fitting the stub axles


The stub axles support the worm wheel and spur gears. To remain clear of the body they can only extend about 1mm outside the chassis side.

I feel that I'd like to be able to remove the axles should the need arise. By making them from axle steel and running a 1.5mm drill bit through the muff, they should be a loose fit.


Then with the muff in the chassis, I feed a 1.3mm drill bit through, then feed in the 2 stub axles, separated for electrical isolation by a slice of styrene.


3 stub axles in place

Others make stub axles from old 1.5mm drill shanks. I can see that this would be smoother than axle steel, perhaps worth trying at some point.