An unknown Twin Marine Oscillator

[Sanjay F]

I've got a little side project going on with with this little Twin Marine Oscillator of unknown origin; so I guess the first question is does anyone recognise it? I can't work out if it's kit built from castings, commercially bought from a manufacturer or handbuilt. The drip trays underneath are made of pressed brass which I don't think most home hobbyists would/could do? Maybe its been made from parts from the Stevens Model Dockyard catalogue (see picture)

The next question is if its single or double acting, I've stripped it down and you can see the ports? This ones a runner after some oiling, makes a change and works in both directions dependent on which pipe you use as an inlet. It has a lot of rust, grime and some modern screws so I'm going to strip off the rust clean the brass, leave the paint original, remove the flywheel wobble if possible and replace the very fine oil pipes leading from the unusual little oil resevoir.

Any information most gratefully received........

<a href="https://www.youtube.com/watch?v=cU8jdC-8ew4" target="_blank">http://www.youtube.com/watch?v=cU8jdC-8ew4</a>

[Sanjay F]

Strip down pictures....

[Jasonb]

Double acting. The steam can go in one end of the cylinder while the other end exhausts ( no open cylinder end) and then as the cylinder angles the other way will exhaust via the hole it just went in while what was the exhaust lets a new load of steam in.

If not from Stevens then there were other makers of similar cylinder sets.

[Sanjay F]

Now that's interesting that pivot, steam block and cylinder from that catalogue look very similar.

Other than Steven's what are the names of other manufacturers of parts from that era? It would be good to have access to their old catalogues as reference material

[Jasonb]

The Macmillan one can be bought as a download from Camden Miniatures, get it before they shut up shop.

To some degree, most of the other names did parts, some more than others so that would be the likes of Gamages, Bassett-Lowke, Whitneys, Avery, Simmonds, etc

[Sanjay F]

Camden Miniatures - wow, they have a lot of material, I got the Macmiillan catalogue, very nice, thumbing through it now. Thanks for the information 

[crueby]

Camden Miniatures - wow, they have a lot of material, I got the Macmiillan, catalogue, very nice, thumbing through it now. Thanks for the information 

Be warned, the owner of Camden books is retiring, shutting down in July. Sad to see them go, I  got a lot of great books from them over the years.

[Sanjay F]

The engine was stripped cleaned and reassembled. I discovered the trunnion pivots are very sensitive and it took a while to get the correct pressure so the port faces engaged without excessive friction or too loose whereby there wasn't a good seal. I see why they put locking bolts on these now, although I assumed they were oil cups when I first saw them 

So the flywheel, yes it still has a wobble, the reason being is not the actual flywheel itself which has been perfectly machined and runs true. The end of the crankshaft is threaded to a diameter which is not close to the diameter of the flywheel centre, it is also very worn and slightly bent 

I could try and fix this by some clever means which I haven't quite worked out or make a new crankshaft or I could just live with it which is sometimes what I feel is needed on these old engines.

I'm quite interested in a solution which does not afford the possibility of further damage as I'm sure I'll come across the same thing at some point in the future:

Anyway, here she is ....................

<a href="https://www.youtube.com/watch?v=1xPptUElFNg" target="_blank">http://www.youtube.com/watch?v=1xPptUElFNg</a>

[Michael S.]

I can't really say for sure why the flywheel is wobbling. However, one possibility would be to drill a larger hole in the flywheel and then fabricate a suitable bushing for the crankshaft thread.
The engine refurbishment turned out well.

[PaulR]

Having the flywheel so far away won't help as any tiny error in the shaft will be magnified the further you get from the bearing. Can you move it closer?

[Sanjay F]

Having the flywheel so far away won't help as any tiny error in the shaft will be magnified the further you get from the bearing. Can you move it closer?

Agreed, and I tried to do that, but the shaft has some dints & gouges in it nearer the bearing; when I moved the flywheel closer the wobble becomes amplified   

[Chipswitheverything]

Well, no doubt at all that this ancient little engine is able to run quite well after all the many years!   Wonder when anyone last saw it spinning?
  The clean up that you got on and did quickly has made quite a transformation to the model's appearance, without , I'd say, removing too much "patination", which was mainly old dirt and some rust!  As the whole construction and design reflects the thinking of an earlier age of model engineering, and has its charm, I think I'd be inclined to just leave the model as you now have it.  Dave

[Admiral_dk]

Great improvement in the Looks department 

Per       

[Sanjay F]

Thanks folks, that was a clean up rather than an engineering exercise and I'm going to leave it as is; maybe in another 100 years or when I'm dead and gone (which ever comes sooner  ) someone will take on the wobbly flywheel!

Here's a picture of it next to a Stuart 10v which seems to be the standard unit of measure when comparing model engine sizes. As you can see it's quite a compact little thing.....