Author Topic: Making a small marine steam engine the beginners way.  (Read 12513 times)

Online Gas_mantle

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Re: Making a small marine steam engine the beginners way.
« Reply #30 on: April 28, 2016, 01:52:02 AM »
Yes Bob I'll do that if you message me your details.

I'm not familiar with Cad drawing programs though, will a few hand drawn sketches photographed do ? I'll add a few explanatory notes too.

Funilly enough for a bit of a fag packet design they work well without any leaks.

Peter.

Online Gas_mantle

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Re: Making a small marine steam engine the beginners way.
« Reply #31 on: May 31, 2016, 03:44:04 PM »
Hi,

I can happily say that now I've made the eccentrics and got one side of the flywheel machined the engine is now nearing completion.

I've tried it running on a small air compressor and both cylinders work well, as yet I haven't made an inlet manifold or a splitter for my airline so I've only been able to test one cylinder at a time but either of them running alone will easily operate the engine without the flywheel yet in place.

It's not perfect by any means and has a couple of tight spots yet to sort out but I'm reasonably satisfied with the result even if it is a bit unorthodox looking - I guess that's how things turn out when you make it up as you go along.

The first picture looks to be leaning because of the camera angle and the uneven length of the protruding bolts on the underside, but it is actually vertical - honest :-)



So far the flywheel is only done on one side and I had a lot of hassle trying to cut the recess but with a bit of luck it will be finished tomorrow.



Just need to make a bearing to support the crank beyond the flywheel and finish of with a few small fittings and decorative extras then it should be ready to clean up and paint :-)



Peter.



Offline Alan Haisley

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Re: Making a small marine steam engine the beginners way.
« Reply #32 on: May 31, 2016, 04:13:44 PM »
Peter,
It looks like you have plenty of room to fit cross-head guides and with the short connecting rod throw it's probably a good idea to do so. Without guides fitted I think that the piston rods will rapidly wear the glands and cost you half your power.

Other than that, I love your work and think that you did a marvelous job for an essentially first engine to your own design.


 :cheers:
« Last Edit: May 31, 2016, 06:12:09 PM by Jo »
Near Raleigh, NC, USA

Offline pgp001

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Re: Making a small marine steam engine the beginners way.
« Reply #33 on: May 31, 2016, 07:38:05 PM »
Don't forget that Peter has built this without using a milling machine, and he doesn't have a workshop as such (its in a corner of his kitchen) so its quite an achievement really.

He came to Doncaster exhibition with me a couple of weeks ago and bought a milling machine from there, so once it arrives it will be interesting to see what he conjures up next.

Phil

Offline zeeprogrammer

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Re: Making a small marine steam engine the beginners way.
« Reply #34 on: May 31, 2016, 10:54:55 PM »
Wow. That's really coming together.
And I like that flywheel. Particularly the inner holes. I've never done a good job on that.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Online Gas_mantle

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Re: Making a small marine steam engine the beginners way.
« Reply #35 on: June 01, 2016, 08:16:59 AM »
Hi,

When I came up with the idea I pondered how to make crosshead guides and thought with the limited tooling and experience I have that I wouldn't be able to make anything accurate enough. I decided that having long piston rods exiting the cylinder caps would be a lot easier and hopefully reduce any wear - it means the engine does have an odd hybrid appearance but for now it is probably the best I can manage. I do agree that guides would be a far better solution though and it's something I have considered adding later. As Phil said I will have a mill shortly and then the possibility of adding guides then becomes more realistic.

As for the flywheel, I've made few smaller wheels in the past and to be honest this is the first one that has looked anything like reasonable. The radial holes were bored by offsetting the wheel mounted on a faceplate and it's about at the limit my small hobby lathe could manage.

Offline pgp001

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Re: Making a small marine steam engine the beginners way.
« Reply #36 on: June 03, 2016, 11:24:35 PM »
Peter

I think it would be good for us all to see a video of your engine once you get it running.
It will show others what can be done with very little equipment.

Phil

Offline b.lindsey

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Re: Making a small marine steam engine the beginners way.
« Reply #37 on: June 03, 2016, 11:45:56 PM »
Peter it looks far better than what I could do with a lathe only. I do think the new mill will open a lot more possibilities for you though. Yes a video please when you can but in any case.... well done!!!

Bill

Offline crueby

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Re: Making a small marine steam engine the beginners way.
« Reply #38 on: June 04, 2016, 12:52:13 AM »
Having the piston rod extend through the top caps rather than using lower guides was a common thing on marine steam engines, keeping them light and compact. The Sabino's Payne engine is that way, been running well for many decades. I think it gives it a nicely interesting action.

Online Gas_mantle

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Re: Making a small marine steam engine the beginners way.
« Reply #39 on: June 04, 2016, 01:35:59 AM »
Thanks for the replies I'll try and post a video tomorrow.

As for the piston rods coming out the cylinder tops, I wasn't aware that was common on marine engines, I did it just to get around the problem of making crosshead guides. The engine is about 24mm bore and 40mm stroke which means with the additional height of the piston rods exiting the cylinder heads gives it a very tall look, If ever I was to make another one I'd reduce the stroke.

Initially when I started building it I assumed a longer stroke would lessen any lateral movement on the piston rods, I'm by no means an engineer but having had a rethink I'm now thinking a shorter stroke and a longer conrod would have been better.

With the benefit of hindsight I think the piston rods could do with being 6mm dia, they were originally 4 mm silver steel but I later modified things so they are now 5mm, unless I remake the cylinder ends I can't increase that.

It's far from perfect but I guess this is what happens when you make it up as you go along :-)

Peter.

Offline crueby

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Re: Making a small marine steam engine the beginners way.
« Reply #40 on: June 04, 2016, 02:04:24 AM »
Here is a shot of the engine I did, inspired, not a copy of, by the Sabino passenger steamer engine. The piston rods go through the caps, as do the valve rods. This setup keeps everything straight, no need for crossheads, runs very well and is a fun motion to watch.

Online Jasonb

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Re: Making a small marine steam engine the beginners way.
« Reply #41 on: June 04, 2016, 01:26:28 PM »
Some traction engines also used front guides in conjunction with some form of crosshead guide.

Its comming along well, look forward to seeing it run

Online Gas_mantle

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Re: Making a small marine steam engine the beginners way.
« Reply #42 on: June 04, 2016, 07:34:18 PM »
I've managed to make a short video of the engine running on an airbrush compressor - I'm on my own so it's not the best video but it does at least give some idea of how it runs.   I don't know how to turn the video through 90* so I'm afraid it's side on :-(

Anyway, at the moment the airlines are just a temporary push fit held in with elastic bands and there isn't yet any gland packing so there should be plenty of scope for improvement once it is complete.

It runs reasonably well at the moment but I think the valve timing is a bit out on the right cylinder and I think the valve rod is slightly too short so the valve is a bit low in its travel and possibly meaning the cylinders are slightly fighting against each other. I'm reasonably confident with a bit of tinkering I can get it to run significantly better. I forgot to show in the video but it will operate about as low as 50rpm.

It's still a bit rough and ready and needs a lot more to tidy it up. 1 or 2 of the bearing blocks could do with moving over slightly to even them up and I need yet to add a supporting bearing outside of the flywheel.

<a href="http://www.youtube.com/watch?v=Z9sxFpdytX0" target="_blank">http://www.youtube.com/watch?v=Z9sxFpdytX0</a>

Peter.

Offline Roger B

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Re: Making a small marine steam engine the beginners way.
« Reply #43 on: June 04, 2016, 08:06:32 PM »
Looks good to me  :praise2:  :praise2: You should be proud of that  :ThumbsUp:  :ThumbsUp:  :wine1:
Best regards

Roger

Online Jasonb

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Re: Making a small marine steam engine the beginners way.
« Reply #44 on: June 04, 2016, 08:37:20 PM »
Thats running well and looks to turn over very smoothly where you were rotating it by hand.  :ThumbsUp: