Beginner making first steam engine

I hooked mine up to the esspresso machine steam pipe with a bit of tube

I'v got a (?) 2 L garden spray pump which is ok for any of my small wobblers, and a Stuart Turner Progress VS, this has a bore of 1/2" and stroke of 3/4", and has a slide valve. we,v just got a ST 10H, must try that one.

Ian S C

Hi all,

Many thanks for the positive comments received.

My postman arrived with my knurling tool and grub screws today so I'm now in a position to hopefully complete the engine.

I've never used a knurling tool before but after a quick look decided to put it to work on a few trial runs before making the bearing oil bolt.

After a few tries using different speeds and depth I ended up with this.

It looked to me worth keeping as the finished product so set about turning it to size and cutting a thread. Since I wasn't able to cut a thread right up to the head using a die I decided to turn a plain shaft slightly undersize just beneath the head. I hope this will allow it to seat flush on the housing once tightened down.

The remaining stock in the chuck came in handy to make a threaded arbour to hold the work whilst I turned it round to face off the head.

5 minutes later and a bit of filing to shorten it and this is the result.

So far so good, I reasonably happy with it.

Now I have grub screws to secure the eccentric and the flywheel I'm able to have a go completing the eccentric rod and attaching it to the valve piston.

I wasn't really sure of the best way of going about this but as a start point pushed the valve to it's furthest travel then use calipers to see how far the wrist pin will be from the main axles centre.

When the piston valve is bottoming out at it's furthest travel the wrist pin hole is nicely aligned with the end of the cylinder block as shown in the photo.

So by lining up the wrist pin hole out side the cylinder I can see where the valve ports lie in relation to the inlet when the valve is at maximum travel. The little indent I've cut next to the hole allows the main power piston to exhaust when the valve hole has slightly gone past the port linking the 2 cylinder bores. So when the valve is in this position exhaust can still occur even though the main holes are past alignment. (I think !)

One last check with the calipers tells be this is maximum travel so the 2 centres on the eccentric rod need to be just a tiny bit less than this distance to prevent the valve striking the far end of the cylinder.

Well it's drilled and filed now, I can tidy it up later once I'm happy it works.

I really hope I've done this last step correctly.

I did put a bit of wire staple in as a temporary wrist pin to give it a bit of a try blowing down the airline. Unfortunately is far too much of a loose fit for the valve to operate properly and I need to make a few spacers for the main axle to keep things in correct alignment and prevent the eccentric strap coming off the eccentric as it does now without a retaining feature on one side.

On the plus side the engine turns smoothly and the power piston does respond nicely to a puff of air.

With a bit of luck it will be finished tomorrow.

Peter.

I hope my first efforts on the lathe are as good as this. I am waiting to see how it runs so any chance of a youtube video link when it is complete ?

Edited By Brian John on 12/07/2015 05:10:12

Hi,

Thanks Brian, I had thought about trying to do a short video. At the moment I don't have a Youtube account but I'll get round the problem somehow and if necessary I open an account on youtube.

Hopefully I'll get the axle spacers and wrist pin made today and set about getting it to work.

Peter.

Hi all,

I set about trying to finish the engine yesterday and hopefully give it a test run.

Firstly I needed a better wrist pin than the temporary staple I was using. It involve turning a piece of brass rod down to about 1.5mm but with care that shouldn't be a problem.

At about 2mm the rod is starting to flex and the tapered cut I'm getting becomes apparent, thankfully the Poundshop sell these blue travelling steadies at 6 for a quid in the biro section

The taper seems to have gone

Eventually I arrive at this,

1.55mm and just right.

Cut to length and the end lightly peined over all seems ok.

The wrist pin needed to be just short of the end of the cylinder at maximum travel and have a 3/16 stroke, so I'm hoping I've achieved that with sufficient accuracy.

With the wrist pin done all that's needed now is a few spacers for the axle and then a test run.

I'm satisfied this is the alignment needed, so I need a spacer with a disc to keep the eccentric in place then possibly another one between the eccentric and crank and finally a small one behind the fly wheel may help.

A steel bar turned at one end to 16mm (the eccentric retaining disc), reduced down to a smaller diameter for the spacers and drilled to accept the axle.

A bit of a makeshift idea but I reckon the eccentric disc/spacer need to be 6.5mm

So using this crude method I cut small reference grooves in the work piece marking the parting cut position. I did the same method for the other spacer hoping I'll get 3 components in one procedure.

Parting tool at the ready and here we go, buy 1 get 2 free.

I took the next photo at the wrong time, it should show the tool further left to part off a disc for the eccentric, but you get the idea.

I end up with these 3 and just a bit of filing and tidying up to do.

Looking like a 'proper' crank assembly.

Well does it work ?

I rigged it up to a Kelly kettle and aquarium tubing and although it coughs splutters and hisses it does kind of work.

The eccentric rod has a bit too much lateral movement and the valve piston is a shade too small in diameter. the result is steam escapes past the valve as it wavers in the cylinder.

I'm going to file down the eccentric today and make a better fitting valve piston in the hope of rectifying what I think is the main issue.

I'm confident it will work though, the valve although a bit sloppy in side to side travel does seem to operate properly.

Peter.

One thing I discovered when building a wobbler engine with no piston rings is that you might find you have a nice piston to cylinder fit when running on air but once heat and steam is applied then things expand...and not always equally. My nicely fitting piston became jammed in the cylinder once everything got hot ! But if you make the piston and valve too small then you lose a lot of steam. I found that it was a delicate balancing act to get it just right. None of this advice may be applicable in your case ; I think it depends on the engine.

Edited By Brian John on 13/07/2015 11:18:54

Thanks Brian,

I'm wondering if it may run better on air anyway.

For reasons I don't understand it works better pointing skyward with the flywheel uppermost !

It's very sensitive to adjustment, I put an allen grub screw in the eccentric to allow for valve timing adjustment but under live steam it soon gets scalding hot and a pain to adjust.

I'm still pleased with it though, it needs a few minor glitches sorting but it does cough an splutter along now if I catch it right so I don't think there's a great deal wrong with it in principle.

Peter.

Many thanks to everyone who followed this thread and offered their encouragement.

I can now say I've got the little engine running on live steam, (I made a new valve piston) it's still very sensitive and struggles when horizontal but rattles along in an upright postion.

Hopefully the fact it runs ok upright suggests there isn't much wrong and it should be simple enough now to sort it out.

I've only had a lathe a few weeks and this was the first thing I made, I've never done anything like this before so although it was a simple project compared to many on this site I'm very pleased with it and enjoyed every minute of making it.

I don't have a youtube account but if anyone wanted to see the engine running I'll resister and upload a video (can I upload one direct to this forum ?).

Peter.

There may be more friction from the cylinder and valve when horizontal but one would hope that it has more power than that. Perhaps if there is slop in the valve the timing is helped by its weight acting in that direction. Trying flywheel down might show this up.
One danger with low pressure steam is that when the valve cuts off it may not be able to expand enough to fill the chamber at the end of the stroke and could be retarding the piston.

Hi Peter

Don't underestimate your achievement! You've taken a few random bits of metal & skilfully worked on them to produce a working steam engine. It doesn't matter that it's not of the same complexity as one of Jason B's masterpieces, the point is you've found somewhere to start, had a bash and cracked it!! I'm sure even Jason started with something simple!

I'd love to see a video of your engine running & look forward to reading about your next challenge!!

Regards Martin.

Great work there Peter, you must be very proud of your achievement.

As this was your first project I certainly look forward to seeing the next and subsequent ones.

Edited By V8Eng on 13/07/2015 18:09:19

.

This is tops.

Nick

Hi,

Here's a short video of it running on live steam, it can be seen how it runs better when upright.

I'm inclined to think it's an issue of water in the cylinders rather than friction problems (when not connected to the steam line it spins freely with little friction)

The Kelly kettle I'm using as a temporary boiler throws out a lot of water and think that's a lot of the problem rather than the engine itself but would be interested what others think is the cause.

**LINK**

Peter.

How much water are you putting in the kettle ? Try it with the kettle only half full and see if that helps. I never fill my vertical boilers more than 75% as water gets into the cylinders and stops the engines from running properly for the first few minutes.

Your next project : silver soldering a boiler

Peter, the aluminium cylinder may cause more condensation than for example bronze, but what ever metal is used this will go away when the engine heats up.

Isn't it great when something you made actually works, and it's great if it's the first thing.

Ian S C

Hi Peter

I've been off for a while and so a bit behind on here, can't believe you've finished already - congratulations..!

Look forward to seeing no 2 project...

Cheers

Garry

Hi Peter

A simple name change from horizontal to vertical steam engine

and jobs a good un !!

Tony

Hi all,

Thanks for the replies.

The irony of it is, the plans had it as a vertical engine with the flywheel at the bottom, I decided to build it as a horizontal but the engine has decided it is a vertical with the flywheel at the top !

Brian - I think part of the problem is the Kelly kettle has a small surface area of water at the top, it also needs to be reasonably full so I get a lot of water entering the tubing in relation to the steam generated. It's far from ideal as a boiler.

Ian - it does run better when it's hot but still struggles when horizontal, it may even improve on its own after it's been run in a bit

Peter.