Removing a flywheel from its crankshaft.

[Tony Bird]

Hi,

I have recently acquired a Twin or Double Beam engine to restore. It is a little unusual and probably a one off. It isn't very large and except for some screws looks complete, it is damaged; the flywheel end of the crank shaft is bent, hopefully it will straighten so a new crankshaft will not have to be made.





The four-bearing crankshaft is unusual in my experience; the split bearings holding it do not directly hold the shaft but what look like Oilite bushes on it. The eccentrics are mounted on ball races and there are semi-rotary valves in the base of the cylinder. The pipe work looks like spaghetti junction, it looks as if it could be an interesting project.




I really shouldn't have started playing with it as I have a couple of projects already on the go and other work. However later today we are going to play trains in Towyn for a few days and yesterday I had an afternoon free; so looking for a small job I decided to take the flywheel off the crankshaft. Three hours later it was still on the crankshaft!

A lot of the model is held together with tapper pins and the flywheel is secured by one. The tapper pin goes into a blind hole in the flywheel and was about 3 mm below the boss of the flywheel, it also rotated so couldn't be drilled out! After a lot of thought it was decided to turn down the boss of the flywheel (it was rather large anyway) until the top of the pin was reached a transverse hole would then be drilled to the pin could be levered out. This did work but took some time to achieve. The flywheel has the number 48 cast in it and perhaps had another life as a lathe's change wheel.






I didn't like the orange/red that the flywheel was painted so it has had its first coat of green.



I suspect that it will be some time before any further work will be done on the model.

Regards Tony.

 

[Tony Bird]

Hi,

Despite the heat I braved the shed for a couple of hours today and did some more work on the engine.

The engine's base support is made from welded square section steel tube with a raised steel edging strip which was also welded.



After the engine and base were removed the support was cleaned and sprayed with undercoat.



The support was then sprayed black and rubber feet fitted.



While the paint dried the engine was removed from its base.



The columns, beams and cylinders were put away and the engine base and the crankshaft supports were cleaned up. The crankshaft supports had their bases relieved and bolting faces machined.




The parts cleaned and painted were put together.




To line the bearings up I will need to get some 5 mm steel then I think next will be trying to straighten the crank shaft.

Regards Tony.

 

[Tony Bird]

Hi,

I had a little time after finishing another job so bit the bullet and had a go straightening the crankshaft. First because it was a weak spot the remains of the taper pin was soldered into the slot in the crankshaft. The pin was then sawed and filed to suit the crankshaft. The crankshaft was then set up in the lathe using a fixed steady, it was found than the bend was only on the part of the crankshaft that held the flywheel This part of the crankshaft was straightened by tapping with a hide mallet.



It was found that the crankshaft revolved OK in its four bearings but the flywheel had about a 1 mm wobble, there must be a slight 'S shape in its part of the crankshaft.

As can be seen in the following photograph the crankshaft was assembled with both the big ends, a bearing and eccentric fitted the other bearings and eccentric are removable.



The engine with the crankshaft fitted.




Just before end of play a column and beam were cleaned up and fitted.



Regards Tony.

 

[ShopShoe]

Tony,

That's going to be very nice when it's finished. You must have a special sense to find your projects and fantastic imagination to see what they can be turned into.

Always follow your adventures.

--ShopShoe

 

[Tony Bird]

Hi ShopShoe,

That's going to be very nice when it's finished. You must have a special sense to find your projects and fantastic imagination to see what they can be turned into. Always follow your adventures.

I am glad you enjoy my efforts.

Yesterday after another project I did a little more to the engine.

The other column and beam was fitted.



Then the exciting part I took the cylinders apart to clean them. Not quite as I thought they would be. The pistons and one of the rotary valves.



As to the cylinders themselves. They cannot be taken further apart unless surgery is considered as they are silver soldered together the other rotary valve being captive.









I must admit I haven't yet worked out exactly what happens when it works. Any suggestions? There is just a single hole in the base of the cylinder. I expect I will just put it together and see what happens.

Regards Tony

 

[Tony Bird]

Hi,

The model was finished and run today.

The semi-rotary valve



Photographs of the finished model.






Any suggestions of what the vertical copper pipe is for? It is connect below the rotary valve on the cylinder which connects through to the other cylinder.

The inevitable video at:

https://youtu.be/vJ47M22QTYY

Regards Tony.

 

[ShopShoe]

Tony,

I'm guessing that vertical pipe is exhaust. I'm trying to decipher the other piping and the valves and it looks like the plan might have been to make some type of a two-stage design, but ended up as not one.....

I'm just guessing.

Anyway, that turned out really nice.

--ShopShoe

 

[Tony Bird]

Hi ShoeShop,

Someone else looking at it said it is probably for oil to feed the valves, which makes sense as the pipe goes under them and nothing comes out of it when the engine is running. The exhaust comes out of either of the two horizontal pipes depending on on which the steam is fed into. Like an oscillating engine you can change the engines direction depending which pipe is used for the steam feed.

Regards Tony.

 

[SilverSanJuan]

Outstanding bit of restoration work, Tony. The engine looks beautiful. :thumbup: