Wolf of Badenoch

Richard Spoors

Western Thunderer
I spent an enjoyable last 18 months with a Finney V2 on my workbench, from which you can see I'm not the quickest of kit builders. I'm a keen supporter of Missenden Railway Modellers, and I sometimes think as much work gets done there as at home. My early railway interest was the ECML with many a happy Friday night as a teenager spent at Newcastle Central station before steam disappeared. To complete my collection of ECML pacifics, I need to look at the Thompson A2's. DJH produce kits of all three classes, so I'm starting with the A2/2. The kit is quite old and follows the DJH practice of designing the kit so that a decent model can be built by the less experienced modeller. Comments on this forum suggest that the weakness in their kits is a lack of detail below the frame. With that in mind I'll be looking to see what additional detail can be added to make improvements.
I started with the main frames, which are quite chunky when compared to the Finney V2. Rather than punch out the rivets, I drilled 0.5 mm holes for Scale Hardware rivets. These were soldered in place using paste and a flame. I chose Slater's hornblocks as I needed a hornblock frame with narrow sides to fit between the lower frame spacers. They also have a useful cast mark showing the axle centre. They will be carefully soldered in place such that the spring retaining pegs are vertically aligned to the correct horizontal level.
Cheers

RichardIMG_0486.jpg
 

7mmMick

Western Thunderer
Hi Richard,

I’m really looking forward to seeing how you tackle this one as I’m building a DJH A2/3 at the moment. I’ve opted to use the Finney hornguides and adapt the frames for the Finney style of compensation. My build thread has concentrated on the tender to date but I’m well on with the loco and should hopefully get a thread update on next week. As you say the bottom end is a little lacking so I’m adding lots of extra castings and detail to bring it up to speed hopefully,

Mick
 

7mmMick

Western Thunderer
Well that makes two A2/ threads to follow.

I wondered what had happened to your A2/3 build Mick.

Ive fancied doing an A2/3 for a good while

Bob

The West Country build took over for a while but i’m Now back on the A2. I have to admit that I’m really enjoying getting back to a prototype I love, it will be a shame to sell it on when it’s finished :(

Mick​
 

LarryG

Western Thunderer
Another one here looking forward to seeing this develop. I only saw the A2-3's.....Thompsons Pacifics fascinated me no end.
 

Richard Spoors

Western Thunderer
Hi Mick, it will be interesting to see how our approaches to improving the kits develops. I'm researching the way in which the slide bars were supported by the motion bracket. On Gresley engines (or at least the V2) the motion bracket was in line longitudinally with the slide bars and a "foot" to the motion bracket extended forward and supported the slide bars with two bolts. When Thompson ditched Gresley's conjugated drive for the cylinder valves and went to the classic Walschaerts drive, the longitudinal centre line of the motion bracket was offset to the centre line of the slide bars. Therefore the joining plate on the foot of the motion was also offset.
Now, if you're building your DJH kit "out of the box" the cylinders are designed 1 mm wide on each side. DJH have done this so that the builder needs to pay less attention to the clearance of the leading driving wheel crank pin.
Having mastered the "scale" clearance on the Finney V2, I've taken the plunge to remove that 1 mm and have scale cylinder width across the frames. The consequence of this (apart from managing the reduced clearance) is that I need to fabricate a small bracket to make the slide bars/motion bracket connection look right.
I've also improved the appearance of the slide bars by inserting a nickel silver strip to make the upper surface look correct. Then I can add some scale hardware nuts.
 

7mmMick

Western Thunderer
Two photos that relate to my post above. The improved slide bar and an image (reproduced only to illustrate Thompson's motion bracket design -copyright RCTS) View attachment 111179

Hi Richard,

I too have been pondering the slider/motion bracket connection. I've found these photo's useful and luckily it happens to be the loco i'm modelling 'Chamossaire'. I'd like the cylinder and motion bracket to be one complete assembly but i'm yet to decide how to do that? Like you some scale hardware will be utilised ;)

A2 4-6-2 | 60514 1961-05-14 Doncaster

I opted to replace the DJH slider with a Finney V2 one as the DJH etched affair just looked too thin and weedy. I do like the way you have beefed yours up though. I've also replaced the rear valve cover, cylinder gland, front cylinder cover and cylinder relief valves with Finney fittings. I just wasn't happy with the fidelity of the DJH WM parts. I did however keep the crosshead as I do like the LW brass casting from the kit. The only thing i've done to change it is to get rid of the brass slide bar and swap for N/S rod. A bit of a faff but I think the effort is worth it. I also stuck with the DJH cylinder taps as they're a nice representation IMO. Here's progress to date, some webs and bolt detail to add but it's almost there.
DSCF4862.jpg

Cheers

Mick
 

Richard Spoors

Western Thunderer
Hi Mick, I like your progress. I’m on a break until next weekend. Did you make your cylinders detachable? When I milled of the 1mm, I prepared the casting by making 2 short brass tubes and tapping them 2mm. I screwed them in position and filled the void with car body filler. Now the inside face is milled I can screw them in position with 2 cap screws.
DJH have much better detail on the masters for their lost wax than whit metal.
Cheers
Richard
 

7mmMick

Western Thunderer
Hi Richard,

Yes my cylinders are removable. I'm yet to create the lateral fixing to the frames but the vertical fixing is as DJH intended. Your idea for some tapped tube will be the way to go I think,

Cheers
Mick
 

Richard Spoors

Western Thunderer
I've persevered with the slide bar support bracket that is an integral part of the motion bracket. The rear needs to be trimmed to align with the motion bracket to which it will be soldered. I used an I section brass channel and four simulated bolts from GHW in Germany. Had I not removed 1mm from the back of the cylinders, the motion bracket would have sat centrally on the slide bar. I've also posted a picture of the rear of the cylinder showing the threaded brass tubes to enable the cylinders to be removable and a photo of the real motion bracket.
Cheers
Richardslide  bar support bracket.jpg machined inner face of cylinder.jpg A2-3 motion bracket.jpg
 

7mmMick

Western Thunderer
Hi Richard,

The prototypical shot is really helpful. I started looking at the motion bracket work and found that I needed the footplate in place so I could be sure the motion bracket fits snugly underneath. So I’ve moved onto the body. With everything fitted the gap between the bottom of the motion bracket and top of the slide bar seems too large? Have you found this is the case?

Mick
 

Richard Spoors

Western Thunderer
Hi Mick, I don't have a problem with a vertical gap, just lateral, hence the little 'foot' I made yesterday. I'm still playing with individual components before fixing anything. Having located the motion bracket in the slot in the frame and bolted the cylinder to the frame this is how it looks:
A2-2 motion.jpg
Although you may have a point, as the slide bars look horizontal, where they should be at a slight slope downwards. More trial and error me thinks!
Cheers

Richard
 

Richard Spoors

Western Thunderer
Following up I have looked at the pipe and rod drawing, a copy of which I have from the NRM. The cylinder angle is 2 degrees and the motion bracket is also canted such that the support to the slide bars is at 90 degrees.
A2-3 pipe and rod.jpg
The foot of the motion bracket scales at 29.5 inches from the footplate. In the model, allowing for the 1.9 mm thick footplate and the height of the etching at 13.62 mm, we have a total of 15.52. so, with 29.5 inches scaling to 17.23 mm we have a gap on the model of 1.71.
In the kit DJH expect the cylinders to be at the prototype angle as they include a canted packing block to fit between the top of the cylinder and the footplate. The compromise seems to be to pack out the foot of the motion bracket before fitting the etched overlay. Of course one could go down the CAD route and redesign the motion bracket etching!
In order to get the cylinders and motion bracket at the correct height on the model, they need to be 'dry' fitted to the footplate. So time to start cleaning up the pewter!
Cheers

Richard
 

7mmMick

Western Thunderer
Hi Richard,

That rings true and confirms the position I am in. I have already fitted the overlay to the motion bracket so this will have to be removed and modified as you suggest. Good luck with the Pewter!! I’ll update my thread on progress after the weekend but I’ve had fun and games to say the least:thumbs::D

Cheers

Mick
 

Richard Spoors

Western Thunderer
Progress with the 5000 gallon tender as I have fitted hornblocks to three axles. The shallow design of the chasis meant that I had to add brass strip to contain the hornblock frames. I used etched frames from Roxey Mouldings. In order to add some detail to the brake gear I will be using castings from Ragstone, complemented with some turned parts to represent the vacuum cylinders. The pull rods are 1.2mm nickel strip. (Only one side is shown). The lateral rodding will be brass tube and the pull rods from the brake shaft to the first cross beam assembled from brass rod with a slack adjuster.

Cheers

Richard5000 gal tender detaling.jpg
 

Richard Spoors

Western Thunderer
IMG_0977.jpg IMG_0975.jpg IMG_0976.jpg
I have found the work of adding detail to the DJH tender quite fiddly and more difficult than I expected when I started out. The body design has the outside frames wider than the prototype, so the main crossbeam had to be widened before the end bearings were fitted. If I make another one I will place the fixed axle bearings to the front as the larger housing for the hornblock fouls the forward pull rods. In order to place the two forward cylinders correctly, grooves had to be milled out to make them fit around the hornblock bearings. The photographs show the trial fitting with all components in place. This confirmed my fear that there is every likelihood of a short circuit from at least one of the brake blocks, so some further filing of the brake shoes is necessary before the hangars are fixed to their pull rods. I shall not worry about the linkages to the water scoop, however, a more detailed part has been ordered from Ragstone. When the tender has been painted the completed brake assembly will be fitted and the crossbeam bearings glued to the frames behind the front steps.
Cheers
Richard
 

Richard Spoors

Western Thunderer
The chunky loco mainframes are designed in such a way that the motor has to be fitted to the centre driving wheel. This presents a challenge when opting for sprung hornblocks as the axle carrying the motor must be able to have vertical movement. Whilst my solution may seem over-engineered, it works!
Here is how I went about it. Using a milling machine and a vertical slide I produced a brass block to fit inside the frames and fit to the diameter of the motor. Finding a mini fly cutter was difficult as the cutting radius is 11mm. My Unimat cutter was too big, but I found one at Arc Euro Trade.
IMG_1458 (1).jpg
This was then attached to the motor with cyno glue and test fitted so that there was a vertical face for upwards and downwards movement
IMG_1459.JPG
I then soldered between the frames a section of 4mm square tube, set against the vertical face.

IMG_1471.JPG
I then made two arms that could be screwed into the brass block. These serve a dual purpose to hold the motor in position and to allow it to move vertically.
IMG_1466 (2).JPG The 'arms' are made from 0.5mm brass strip. The challenge was to make them both the same size and to the correct depth to fit over the square tube in the frames. To cut a folding line in the brass strip I used a centre drill as a milling cutter in the mill, and slowly cut the folding lines 0.05mm at a time. The folds were then reinforced with a touch of solder.
IMG_1469.JPG The finished work with the motorised axle able to float in the hornblock, seen here at its uppermost position. The chassis and motor also fit the prepared slot in the boiler without additional cutting being necessary.

As I said at the beginning, this might be over-engineered, so it would be interesting to hear how others have managed to fix their motors in position longitudinally with vertical axle movement.

Cheers

Richard
 
Top