Has anybody built the steam engine kit : (40701) Liegende 12/36 ?

[JasonBModerator @jasonb]

5/32 x 40 seems to be about the smallest thread about, the Stuart ones look nicer and a bit less bulky than the ones in your link.

They can be made on a lathe

[Brian JohnParticipant @brianjohn93961]

I think the only place it could fit is in the middle of the cylinder cover but it might look a bit strange . I would have to make a new cylinder cover to take the drain cock. I do not see where else it could possibly go on such a small engine.

[JasonBModerator @jasonb]

Another option if you don't want to make small ones is to run two small say 1/16" (1.5mm) pipes, one from each end of the cylinder and tee them into one small globe valve.

A drain cock in the cylinder cover s not unknown on full size but you would only be draining half the condensate, you would need something on the piston rod side too.

[Brian JohnParticipant @brianjohn93961]

On the piston rod side some of the water can find its way out through the gland packing. I think the main problem is on the cylinder cover side. It is not too much trouble to make a new cylinder cover threaded to take a drain cock but I cannot see anywhere that I could put a drain cock on the piston rod side…there is just no room.

Is this a drain cock threaded M4 ?

**LINK**

[JasonBModerator @jasonb]

Yes, continental Europe tend to use metric threads and M4 is almost the same dia as 5/32" . If you do get one then the thread is likely to be metric fine so M4 x 0.5 rather than metric coarse M4 x 0.7 so you will need the right taps

[Brian JohnParticipant @brianjohn93961]

Okay, thank you. I did buy M2 to M6 metric fine taps when I bought the metric coarse taps from Arceuro ; I have only used them once until now. I am glad I did not buy the metric fine dies…very expensive !

[Brian JohnParticipant @brianjohn93961]

They are out of stock of drain cocks. They have also advised me that they are metric coarse which is a bit surprising ; most of their larger threads of M5 and above are metric fine.

[Brian JohnParticipant @brianjohn93961]

I have ordered a set of 3/16-40 drain cocks from Live Steam Models in the UK which have not arrived as yet. In the mean time I remembered that I did not polish this flywheel because I did not have a lathe when I built this engine. The flywheel was machined but not polished. So I mounted it on a mandrel, gave it a light machining to removed the paint and a few wobbles and polished it up. The engine runs very well now that a displacement lubricator has been fitted.

When fitting drain cocks, should some sort of thread sealer be used or is it not usually necessary ?

 

Edited By Brian John on 23/07/2016 08:00:25

[JasonBModerator @jasonb]

You usually need to use a compressable washer to get them to be tight in the right position and this is often enough to form a seal, a bit of your liquid gasket on the thread won't hurt.

Is there room to get 3/16" ones in there or are you going to use tube like I suggested?

[Brian JohnParticipant @brianjohn93961]

I was just going to put one in the middle of the cylinder cover and see how that goes to start with. I will probably have to make a thicker cylinder cover depending on how long the thread is on the drain cock. I will know more what I am doing when I have it in my hands which should be next week.

[JasonBModerator @jasonb]

As I said above that will only do one end. Also it is better to have it as close to the bottom of the bore as possible not central to the cylinder.

Edited By JasonB on 23/07/2016 09:15:21

[Brian JohnParticipant @brianjohn93961]

I think enough water escapes from behind the cylinder through the gland packing. There is nowhere to fit anything there. To start with I want to just fit one drain cock on the front and see what difference it makes.

There is not much room at the front either and I think it will probably have to go in the centre due to the small size of the cylinder but I will see when the drain cocks get here.

What sort of engine is that above ?

Edited By Brian John on 23/07/2016 09:21:48

[JasonBModerator @jasonb]

If you are loosing water out teh gland then its not sealing very well cure that and the engien will run better.

Horizontal Oscillating engine, quite possibly American design. Its on my to make list probably 1/2 or 1/3rd scale

[Michael GilliganParticipant @michaelgilligan61133]

Posted by JasonB on 23/07/2016 09:08:49:

.

I like that !!

… Looks very 'purposeful'

MichaelG.

[Brian JohnParticipant @brianjohn93961]

And its purpose is….?

[JasonBModerator @jasonb]

As the description says, it's a workshop engine. Would have been the small electric motor of it's day and powered something small in a workshop probably purposeful enough to drive your little Opti lathe.

[Brian JohnParticipant @brianjohn93961]

The engine runs much better when I loosen that rear gland to let the water out. I tested it today with the gland packing nut slackened right off and it ran okay. The piston rod must be making a decent seal where it passes through the rear cylinder cover. If I tighten up the gland nut then the water gets trapped in there. There is no room to fit a drain cock on the rear ; the engine is just too small for that.

What is the smallest drain cock you have seen on any engine ?

These look quite tiny : look at the new Apollo engine (very expensive).

**LINK**

[JasonBModerator @jasonb]

As I said earlier commercially 5/32 or 4mm seems to be about teh smalles but you could make them smaller. The ones on that Apollo are a different design and probably a bit easier to make.

As I said earlier in the thread you don't have to have the cock next to teh cylinder. It would be easy to drill a 1.5mm hole and solder a piece of copper pipe into that and put the drain cock on teh other end of the pipe wherever it is easy to get at.

If the gland is easily letting out water it will also be letting out steam so not sealing as it should.

[Brian JohnParticipant @brianjohn93961]

The 3/16-40 drain cocks have arrived from Live Steam Models in the UK. They look quite nice. Would you fit them directly to the cylinder head cover after drilling and tapping it or solder in a pre -threaded bush first ? Using the bush would make it easier to position the tap in the upright position.

There are four drain cocks in the set : 2 X RH and 2 X LH. I am not really sure what the difference is as they look exactly the same. Can somebody tell me what I should look for ?

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