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Cwmhir - The camera never lies


Darwinian
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More progress on the Aberdare as well as painting and installing the buffer stops.

 

Checking the instructions for the loco I found a top /plan former for the firebox is included. Not mentioned in the instructions. Oh well I’ve managed without it. The saddle parts are done but not fitted. Today I spent an hour fitting the outside axle box retainers and the volume springs to the outside frames. All went surprisingly smoothly using 145 solder to tin the brass and then low melt to fix the white metal parts.

 

Should be able to paint the chassis and get it working now.

04E3922B-F594-4618-8FFC-0864ECF86E77.jpeg

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The proper wheels are in along with the motor/gearbox. The chassis alone goes around 3rd radius and looks to have enough on the axles for the outside cranks.

It pushes through my track work OK but once the body is on the pony truck derails on turnouts. Think it is catching on the back end of the vac pipe. Hard to see when right way up. Will have a thorough investigation tomorrow.F374B4E1-09B5-4085-BAB0-ADF90D702C4C.jpeg.d984cdefe749e2fd9ccb6c1199c62bf4.jpegGetting the motor/gearbox inside the boiler/firebox is very tight. I had to cut open the rear firebox bulkhead and cut off the motor shaft at the pickup end.

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Having assembled the chassis I realise that the brake pull rods just stop behind the cab steps, waving around in mid air. I looked at my Finney bulldog and it has steam brake cylinders there but there were none in this kit. A quick check on Brassmasters web site shows the castings but doesn’t list them as for the Aberdare. I assume they should be on the loco so I’ll do a bit of checking and maybe cobble something together.

I have also found that the motor support chassis spacer makes it very difficult to get the footplate on now that I have the boiler front attached to the footplate. Will have to take a few mm off the motor support.

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  • 2 weeks later...

Progress update. Putting it all together part 1. I assembled the tender although the tank/footplate doesn’t sit fully down on the frames. Will need to take a bit off the tops of the springs as they catch on the valances . Also no allowance was made at the rear of the frames for the buffer housings projecting through the buffer beam. I had to resort to filing off about 2mm from the frames. It doesn’t show behind the steps anyway.

Here are loco and tender standing on 3rd radius but only just. I doubt the loco will really be able to grind round as the flanges are tight to the railhead. Good job there are no curves quite this tight on Cwmhir.

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Edited by Darwinian
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That's coming along beautifully, it's good that you are sharing with us the wrinkles you have had to iron out along the way. Very often I have come across a snag and immediately thought: Have I made a #*%@ of this? Sometimes it stalls your progress and enthusiasm until you realise that they are probably all like that.

I'd like to concoct an excuse to have an Aberdare on my layout, other than rule 1 !

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43 minutes ago, MrWolf said:

......

I'd like to concoct an excuse to have an Aberdare on my layout, other than rule 1 !

I just claim it’s on a trial/shake down run up the valley to Cwmhir from Caerphilly workshops. I doubt an Aberdare made it up a valley in Rhymney territory otherwise. Especially as it has to return tender first.

My 28xx and ex-ROD 2-8-0s are really pushing that excuse but I do like big freight engines.

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The Aberdare always looks to me like it was a design intended for some colonial railway that got Anglicised. I think it would look quite at home in Rhodesia or India sporting a cowcatcher and a tropical cab with shutters. They're very different animals, probably why I like them

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  • 2 weeks later...

Problems arise. I fitted a current carrying hook with additional spring wipers to the tender and wires to the loco motor. Here’s the business end of the hook.

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On electrical testing there’s a frequent short circuit in the tender. An insulated wheel rim must be touching the the bodywork somewhere.

I also cannot get the loco motor/gearbox into the body now the wires are on. More fiddling and faffing needed.

Encouragingly the loco chassis seems to run OK when the motor is wired directly.

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I recall seeing several kit built locomotive tenders over the years that had narrow strips of insulating tape out of sight down the inside of the frames. Crude but effective. Clearances and the resulting short circuits must be a common problem.

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Found the short on the tender. The cross wire between the frames holding the rearmost pair of brake hangers had come out of its locating hole on the insulated side, allowing the brake shoe to touch the wheel. Repositioned and super glued and all is well.

Now to sort out the wiring clearance. Then I can try to run it in a bit as the mechanism isn’t as free running as I’d like. Although it’s not been lubricated yet and with outside bearings as well there are a lot of bearing surfaces.

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Tender now running nicely. I took some metal off the back of the pinpoint bearings at the compensated end and substituted a length of blunt ended 2mm rod for the pinpoint middle axle. 

 

Then disaster, hooked it together with the loco on Cwmhir, applied power, whirrrrr but no movement.

I thought I’d forgotten to tighten the grub screw on the final drive cog but no, the outside cranks on the driven axle were loose and one had split. Looks like the plastic Gibson cranks aren’t up to this job. Only option I have is to try to adapt the etched, laminated cranks intended for Ultrascale stepped axles.

Any other ideas?

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There is a recent topic in the kit building/ scratch building section on soldering outside cranks to axles. I think that’s what I did on my Bulldog, although it ha Ultrascale wheels.

 

From those discussions I think I will give it a try first. If I can keep the cranks close to an interference fit I should be able to solder them without the quartering moving. I use a GW models quartering jig to set them up.

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It’s a long time since I have done any outside cranks but I seem to remember using Loctite. No good with plastic though.

 

Brian

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On 01/07/2020 at 17:30, Mrs Durby said:

How about a piece of c.1mm steel sheet and a pillar drill? 

 

Hopefully it won’t come to that. I do have some nickel silver sheet but no pillar drill and it still doesn’t solve the fixing to axle issue.

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15 minutes ago, Darwinian said:

... and it still doesn’t solve the fixing to axle issue.

True.  I had the problem of a slipping o/s crank on a Pannier.  Resolved it by removing the offending, grinding a slight slot into the side of the axle (slitting disc; depth c. 0.4mm) then replaced it and drilled out the 'D'-shaped hole into a 0.9 Dia. hole, then tapered a bit of 1mm brass rod, tapped it firmly in and trimmed off the end.  
Seemed sensible to do the other 5 while I was at it so I did and it hasn't slipped in the 10+ years since !  

 

Oh, and you don't need to make your own cranks if you can fettle Romford ones... ;)

Edited by Mrs Durby
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Cranks duly assembled. I built up 3 laminations and added a washer on the back to provide clearance for the hornblocks bottom strap which fouled the crank otherwise. There are 4 laminations in the kit but that left no side play. The washers are only 1/2 thickness. Crankpins countersunk in and soldered in place.

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The cranks were carefully reamed  out with a taper reamer until a test axle could be pushed half way in. Then I mounted the cranks in the GW quartering jig and squeezed up onto the loco axles as far as I could. Checked the first two axles ran smoothly with rods on. All being well I put the axle across the vice and forced the cranks fully home. I have soldered them from the front face as well just to make sure. I suspect the force fit will be sufficient anyway. Here’s the first axle done.

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  • 2 weeks later...

Late afternoon pick up goods brought up the valley by 850 class pannier 1931. Photographed by from the goods yard by Dai-the bread on his rounds, collecting flour from the goods shed.

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Moving the brake van off the rear.

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Bit more done on the Aberdare. I gave up on the American pick up system as I could not get reliable contact to the tender without having issues with the tender staying on the track. Wiper wires now fitted to the insulated side.

I also fudged the whistle mounting. The instructions say to cut the whistles off their straight stems then drill 0.3mm and fit wires bent to a sort of P shape. I didn’t think I could manage that so turned the whistle manifold upside down and just bent the turned stems at a right angle.

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1 hour ago, Mrs Durby said:

Shame about giving up with tender pick-ups.  There are several ways round that if you find 'drivers only' pick-ups unreliable.  Just ask... 
Did you hang the tender front on the loco draw-bar for extra weight?  

No I had the loco drawbar testing on the tender hook. I realise I hadn’t thought through the loco - tender contact clearly. 6 wheel pickup with compensation on the loco should be fine. Thanks for the offer of help.

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