What sort of bolts/screws are these on this Beam Engine ?

[Brian JohnParticipant @brianjohn93961]

I have ordered a range of hex tools from Model fixings which should be here in a few weeks. Once I have the screws and bolts out then I can measure the length of them and work out what to replace them with.

Where can I order some springs…who has a big range ?

[Brian JohnParticipant @brianjohn93961]

I have found Lee Springs and they seems quite good :

**LINK**

So once I get that spring off the valve cover I can measure it. Should I be looking for something about 3/4 as strong…..1/2 as strong ? Or perhaps order a range of springs and try a few ?

[Ian S CParticipant @iansc]

Brian, it might be worth shortening the original spring, try a turn at a time, you might even have to stretch it a little. It helps to save old springs from equipment.

Ian S C

[Brian JohnParticipant @brianjohn93961]

Yes, I will try that eventually. First I will just have a look and see how that valve system works. Then I will try to eliminate any friction in the system ; I think the crank is rubbing against one of the supports. There may be other points of friction. I have to wait for the tools to arrive from the UK.

Edited By Brian John on 10/01/2015 12:28:13

Edited By Brian John on 10/01/2015 12:29:31

[Brian JohnParticipant @brianjohn93961]

I have dragged this beam engine out to have a look at it today. The previous owner/ builder had TWO springs on the valve nut. I have found a replacement spring with less tension but I am having problems getting this engine to run at all. I have never fiddled with a beam engine before : how do I go about setting the timing ? I thought I could work it out but after two hours I must admit defeat and ask for help.

Below are some photos showing the valve arrangement. The bottom photo shows the springs : the original two springs are on the right. He had used one inside the other. I suspect he had problems getting it to run which is why he sold it !

Edited By Brian John on 16/08/2015 13:59:53

Edited By Brian John on 16/08/2015 14:01:36

Edited By Brian John on 16/08/2015 14:02:31

[Neil WyattModerator @neilwyatt]

Looking at the top picture, it appears that if the flywheel is rotated 45 degrees clockwise the beam will be roughly horizontal and the valve will be roughly at the mid-point of its travel.

This suggests the eccentric is about 90-degrees out from the correct position.

The starting point should be to have the valve at approximately maximum travel one way or the other when the piston is at its mid point (beam horizontal). The engine should then run and the eccentric can be adjusted to get the best result.

You are aiming for the valve to open just as the piston approaches TDC, whatever type of steam engine it is.

The double spring was probably needed to to stop the large rotary valve lifting and leaking with steam pressure applied.

Neil

[Brian JohnParticipant @brianjohn93961]

Thank you Neil. I have been working on it today and I understand the timing much better ; the engine is running quite well. Plenty of lubrication and a new spring over the valve cover has helped too. The engine will even start without touching the flywheel now. There is still a bit of a clunk/knock but it is nowhere near as bad and I suspect that this is as good as it gets. I have fiddled endlessly with the length of the connecting rods but it does nothing to eliminate it . 

Edited By Brian John on 17/08/2015 08:05:35

Edited By Brian John on 17/08/2015 08:07:21

[Douglas JohnstonParticipant @douglasjohnston98463]

I am not a model maker myself, but to me the polished brass finish looks very nice and I can't quite understand why you would want to paint it. Is this to do with making it look more in keeping with the original machine?

Doug

[Brian JohnParticipant @brianjohn93961]

Partly that and also personal preference, But I have decided NOT to paint this beam engine. My lathe will be sent up to me later this week so I will be building my own beam engine.

[Brian JohnParticipant @brianjohn93961]

There is still a slight ''bump'' at the end of the stroke but it is running much better than it was. This is my first video with the new phone so I hope it works.

**LINK**

[BazyleParticipant @bazyle]

If there is a 'bump' it is due to play in the linkage not the length. Quite difficult in a small model to get joints loose enough to move without being sloppy.

Glad yo have decided not to paint it. It is clearly designed to be a shiney coffee table 'talking point' model and paint would halve the value apart from making it look like a kids toy rather than an executive model.

When you get the screws out please replace them with hex bolts, Those ones with piddling little hex holes look bad even on modern instruments – they are just a bad design. The previous owner told you what the screw sizes are – numbers like '6-32' are how the small UNC and UNF american screws are described with the second number eg 32 being the TPI.

What you need is a class case to put it in to reduce the rate of tarnishing.

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