The Craftmans Shop > Model Engineering

Assembled Cylinders

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Yorkshireman:
As requested, pictures for you addicts.

The BR74 Project at Berliner-Eisenbahn is using assembled cylinders, no castings, built up from plates, turned parts and some castings.
The exact detail is a little secret... All nuts and bolts visible from the outside are to scale.

This is for a 5" loco in 1:10 scale. The cylinders are quite large, larger as some the cylinders of some 7,25" locos, see the ruler.
The cylinders have pistonvalves with inside admission. The exhaust from the rear end is routed by an extra channel through the cylinder block to the front. This system was used in many of the Prussian designs.

Today, I completed the assembly of the cylinders, almost. The cover around the cylinders was made from some copper sheet which was handy. The draincocks are like the originals.

Have fun
Yorkie

bogstandard:
Hi Yorkie,

Was the original design of the cylinder like you have produced, using tubes and endplates?. Or was the original a complete casting, and you are just replicating the outside detail?

Whichever way you look at it, it is a very innovative design, to produce a locomotive cylinder from just tubes and plates.

I was just asking because during the war years and immediately following, producing castings I think would have been rather difficult, and the tube plate method might have been used on the full sized loco because of supply problems. I am sure it would have worked just as well in full sized.

Bogs

Yorkshireman:
Hallo Bogs
It is a cost saving method. Of course the design of the KPEV (Royal Prussian Railway Authority) of 1912 was using solid cast iron cylinders. This approach avoids any complex milling operation e.g. for the steam channels, as these are now tricky holes in the sandwiched plates.

Some modern (reconstructed) locos at the small railways in Wales now have been built using exactly this approach! In case the old wooden patterns of the cast cylinders are lost, than this is the method of choice.

Yorkie

bogstandard:
Thanks for the fast reply Yorkie.

I had guessed it was a way to make it cheaper, castings nowadays cost the earth.
 
Your reply has confirmed to me that it is a viable proposition in full sized as well.

Maybe the stalwart model loco builders in this country should be looking at methods like this, rather than being ripped off by the usual suppliers who sell awful castings for top end prices.

Bogs

sbwhart:
Hi Yorkie

Thats very interesting thanks for showing.

I've seen a similar fabrication method for cylinders employed by a chap in Sweden (i think), but he silver soldered the parts together, from your pics it looks like you've bolted the parts together with liquid gasket seals is this correct?.

Cheers

Stew

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