7mm On Heather's Workbench - the answer to life, the universe and…

Heather Kay

Western Thunderer
Graham, you are quite correct. Call it general idiocy on my part. If the client had constructed the slidebars from the etch, rather than the cast ones, I suspect this detail would have been catered for.
 

simond

Western Thunderer
Agree with the above. I do have one loco that has a rectangular relief in the lower slide bar, which from memory is cast. I'd have to look, but I'm at the office. Late lunch.

Best
Simon
 

Scale7JB

Western Thunderer
Interesting thread as I'll admit to knowing GW engines pretty well for obvious reasons..

Yes, Damper controls are directly behind the boiler just to the left of the firebox door and mounted on the floor..

JB.
 

Heather Kay

Western Thunderer
Right, it's Tuesday so that means 4250 day at Snaptophobic Towers.

While there is still a little work to do under the running plate (vac cylinder and associated connecting gubbins for one) I'm beginning to get serious about mating the resin boiler to the metal bodywork.

image.jpeg

Now, I had a similar issue with the WD, where the rear of the saddle casting covered the bottom rings of rivets on the rear of the smoke box. In that case a subtle bodge was used to disguise it. In this case, I'm not quite sure what is amiss.

P1040547.JPG

Here's the real thing. You can see on the right how the saddle stops short of the riveting. Hmm. Sadly the reference photos kindly shared by fellow Thunderers don't let me count the saddle bolts. The kit has 10, and if I can prove the real thing has 9 then I will be able to file away with abandon. If it's supposed to have 10, then I may have to bodge the rivets again.
 

Dog Star

Western Thunderer
Heather, the angle of your photo of the model may be tricking me to think so... looks like the saddle casting is displaced to the rear of the cylinders. What does the situation look like when the saddle and cylinders are aligned on the same centreline?
 

Heather Kay

Western Thunderer
I think it's the angle, Graham. I've slotted the parts in where they are meant to go.

Further investigation of the drawing I have reveals some fundamental truths. The smoke box saddle and smoke box are actually correct as far as I can ascertain. The error, I think is the parallel ring of the boiler: it's too long, but I can't prove this without knowing what it should measure from the back of the smoke box boiler band to the back of the first ring band.

If anyone can provide that dimension, I would be obliged.

So, client consultation will ensue. The options are to sand away the rivets where the saddle sits and pretend it's not a problem, or cut the boiler behind the band in front of the tanks and sand it away, replacing the band later.

I think I am turn to backhead detailing as light relief!
 

Scale7JB

Western Thunderer
Looks to me like the whole boiler needs to move back in the frames for the smoke box rivets to clear the saddle.

Just had a look at a few 42xx pictures on Google, and if you look at the distance between the front of the smokebox and the front footplate supports, at the smokebox end it looks far less distance than what you have on the model in your picture..

JB.
 

SimonT

Western Thunderer
Heather,
I read your posts after answering your e-mail and noticed something new to me.
IMG_1938.JPG

This photo shows where I am with this problem. I found that the boiler wouldn't sit down on the saddle due to it interfering with the motion bracket. There is no cutout in the cladding for the motion bracket, which is what I have seen in the photographs that I have. I accordingly removed resin from the boiler to make the cladding cutout and the boiler now sits true. My weightmetal saddle was beyond use so I printed a resin one and the black prototype is shown in place in the correct position; it is the correct size referenced from the whitemetal one as I didn't have a drawing at that time. What has caught my eye is that when the saddle is correctly positioned, it fouls the rear double ring of rivets. Your restored engine shows that the double row of rivets sit clear of the saddle.
I'll try to do some serious measuring off the GA to see if we can find out what is going on.
Simon
 

Heather Kay

Western Thunderer
Aha! Thanks for that, Simon, and for the email.

image.jpeg

This is the same area on my build. The motion brackets meet the outside of the cladding in my case - or will with a spot of fettling.

I wonder if there have been a couple of attempts at this moulding by JLTRT, neither of which quite hit the mark? I've asked Laurie if there's been an updated moulding which sorts out the extra length. I found a diagram with dimensions from the chimney centreline to the leading edge of the band in front of the tanks. It claims 5ft, which in our money is 35mm. Applying the vernier showed the extra length in the parallel section to be something like 2mm, perhaps a shade more, which is why the smokebox is too far forwards.

I've contacted the client, who has given the go-ahead for a cut-and-shut to move the smokebox back. I'll not perform surgery just yet, as I wait to see what Laurie says first.

Back to the cab detailing. So far I have got clips to hold the roof, and begun to add the condenser and whistle chains.
 

adrian

Flying Squad
I've contacted the client, who has given the go-ahead for a cut-and-shut to move the smokebox back. I'll not perform surgery just yet, as I wait to see what Laurie says first.
Again it is hard to judge from the photos but it does look as though the front of the smokebox and door is overhanging the front frame drop too much, so the cut and shut would help. How does it look with the chimney in place?
 

Heather Kay

Western Thunderer
Again it is hard to judge from the photos but it does look as though the front of the smokebox and door is overhanging the front frame drop too much, so the cut and shut would help. How does it look with the chimney in place?

The centre hole in the top of the smokebox is shifted forward of the steam pipe holes on the running plate. Cutting and shutting will cure a whole host of evils, it seems.
 

oldravendale

Western Thunderer
Once again I wonder whether these photos are of any help. These are all at Barry but therefore exactly as withdrawn. Frankly I don't think they add anything to the knowledge but it's all worth a try.

I'm including the 72XX class as the relationship of boiler/smokebox to footplate is, I believe, identical.

All photos my copyright again.

4247.  Barry.  9 Nov 1968.  FINAL.  Photo by Brian Dale.jpg 4248.  Barry.  18 November 1967.  Photo by Brian Dale.  Final.jpg 5224.  Barry.  18 Nov 1967.  FINAL.  Photo by Brian Dale.jpg 5239.  Barry.  18 Nov 1967.  FINAL.  Photo by Brian Dale.jpg 7200.  Barry.  9 Nov 1968.  FINAL.  Photo by Brian Dale.jpg 7202.  Barry.  9 Nov 1968.  FINAL.  Photo by Brian Dale.jpg 7202.  Barry.  18 Nov 1967.  FINAL.  Photo by Brian Dale.jpg 4222.  Barry.  18 November 1967.  Photo by Brian Dale.  FINAL.jpg 7200.  Barry.  18 Nov 1967.  FINAL.  Photo by Brian Dale - Copy.jpg
 

Heather Kay

Western Thunderer
Brian, thank you for those images. The last one of the 7200 really shows the massiveness of the type to good effect. The bunker shot will be useful, too.

The consensus seems to be to cut and shut the boiler. This moulding is in a grey material, so hopefully I won't need to worry about blunting cutting instruments with the glass reinforcement that is supposed to be used in the makeup of the blue mouldings.

Meanwhile I've been losing myself in invisible details in the cab.

image.jpeg

The condenser - I'm sure someone told me its purpose once - and the whistle chains, of course. There's also a rudimentary ventilator grab handle. The roof now has four brass wire peggy-springy-thingies to hold it on the body.

image.jpeg

The fireman has acquired a pep pipe and tap, as well as a Minion. Oh, sorry, that's actually the side tank water gauge. There's a warning plate to go on this side sheet, but that can go on after painting.

I think the backhead details will wait for another day.
 

SimonT

Western Thunderer
From my digitising this area of the GA, I think it is all down to small dimensional differences all working in the wrong way. I measured my 72XX with calipers. On the drawing the GA is in purple and the model is in light blue.
72XX Smokeboxes.jpg
On the right I have overlayed the two drawings. The DA 52XX has a saddle that is only 26mm deep. The jpg has washed a lot of the colour out so I have attached the pdf.
Now, I need to work out what I'm going to do;)
Simon
 

Attachments

  • 72XX Smokeboxes.pdf
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