Chimney Base Project (photos in Gallery)

  1. Hi

    My current project at the railway is the fabrication of a new chimney base for our loco No.14.

    Built in Leeds by Hunslet the 2-6-2 Side Tank was built for the Sierra Leone Railway back in 1954. When the railway closed in 1974, SLR No.85 was repatriated by the Welshpool and Llanfair Light Railway and renumbered No.14. It has never been named and still carries the SLR plates and still referred to as SLR85 by many of the crews.

    Over the years the chimney base has been rebuilt (doubled over on the inside) a couple of times but the hostile environment of soot and damp corrodes the material quite quickly and it is now paper thin in places. The material looks to be about 4 mm (probably 3/16” in old money) but we have decided to go for something a bit thicker this time, like 8mm. So far we have had two rings made, one the base diameter of the chimney barrel, and a second one the diameter of the chimney base, which is also curved to fit onto the smoke box top.

    The plan is to locate the two rings in their correct juxtaposition and form the compound curves between the two rings using strip material, as we do not have the skill or facilities for heating and manipulating 8mm plate to form such complex shapes.

    The photos show the jig that locates the two rings and one of the first strips in place. When all the parallel strips have been put in (where the arrows are) the idea is then to infill with tapered strips. After welding is completed then it’s a bit of an angle grinder job.

    Thanks for looking (if you have ;) )Watch this space :)
     
  2. Hitch

    Hitch Moderator Staff Member

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    Looks like a long job cappy!! But a great idea if you havnt the facilities!
     
  3. Hitch

    Hitch Moderator Staff Member

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    Once you have welded it all up, take the worst off with a grinder wheel, than a 24grit fibre disc (7") with a flexible backing pad, will work a treat to give you nice smooth curve, than maybe go over with a finer one to take out most of the scratches.
     
  4. malcolm

    malcolm Hej!

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  5. Hitch

    Hitch Moderator Staff Member

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    11,959
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    We occasionally do railway resto bits, i love doing them.
    Did a lot for the the Llangollen railway a while ago.
     
  6. Thanks for the encouragement, yes it certainly is going to be a 'steady old job' as they (whoever 'they' are) say. :D

    If you fancy seeing SLR 85 in action then I have a couple of short clips on YouTube here's one:-

    http://www.youtube.com/watch?v=fcM6wu7H9Ns

    S'bit blurry in part, maybe part due to the internal camera stabilisation and the file compression, hoping to make a better DVD quality one next year, but gotta get the base done before all that :D :D :D

    Have also got some video footage of the first strips for the chimney base being heated and bent so I can hopefully grab some stills from it which I will add to the gallery, plus put some more up on YouTube. The shots are for the railways journal but hope you don't mind me sharing them with you.

    Not too sure about the original method of manufacture but am probably going to the railway at the weekend, just to drain the boilers after the Santa Specials, so I'll have a peer into the archive and see what I can find out, you've got me thinking now :) :D

    Thanks
     
  7. Hitch

    Hitch Moderator Staff Member

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    Just so you know, origianally they would have been a casting.
     
  8. Well it seems that the old boys at Jack Lane (the Hunslet Works) had other ideas :) :) I had a peer at the drawings yesterday and the spec is for the base to be made from 5/16" Steel Plate no more information than that.

    Difficult to ponder the reason why, if it was a stamping then there were tooling costs to take into consideration, though they did build a lot of narrow gauge locos so maybe there was quite a demand for such a thing. As a lot went for export I suppose that repairs to a steel base by welding would be a lot better than waiting for a new casting to arrive.

    As the chimney that fits to the base is quite tall I wonder if there was some concern about a) riveting the barrel to the base securely and getting it gas tight, b) the strength of a casting, given it's inflexibility, with the weight of the barrel and cap attached to it. I know mainline steam uses castings but they are a lot dumpier with the base and cap as one single casting.

    Only the chimney cap is casting, which has cracked in several places. The cracks start from the holes where it is riveted onto the barrel, and pushed out by the build up of rust between the cap and the barrel. Last time I rebuilt it I had to bronze weld the three pieces back together, this time we're going for a new casting :)

    Got four more strips fizzed in yesterday :)
     
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