A Marine Condensing Engine

[Ramon WilsonParticipant @ramonwilson3]

Well I do have DRO on the mills Derek but none on the lathe. My last three years at work was spent programing and operating a Haas twenty tool machining centre. No CAM – all hand typed G code. Loved the challenge of learning it and found it immensely satisfying to see the machine work as anticipated but it's not for me now – that's twenty years ago – I'm well past my sell by date as far as doing it all again is concerned.

The thing I like most about machining from solid is that you are in full control of the shape and not at the mercy of the foundry man. Obviously there are limits but it's surprising how convincing it can be with some thought (and JBW!)

Jason, 10ba –  I 'found' the castings somewhere after I began this project – they stated the scale was '4:1' whether that was 4:1 as drawn compared to a full size or 4:1 from the full size dimensions as drawn I'm not sure. Looked very expensive though.

Yes I knew Rod had CNC but thought he had converted his mill – Rod?

Brian, long time no see/speak – hope everythings well at the Norwich end. Good to see you looking in, my regards to the guys if and when you see them. Maybe a LowMex this year – who knows?

Regards guys – Tug

Edited By Ramon Wilson on 19/02/2021 17:36:15

[ChrisHParticipant @chrish]

Having downloaded and printed off the pdf on this engine and then gone through and studied all the drawings, although not read all the construction notes at this stage, has given me a far greater appreciation of what has gone into your condenser to replicate by fabrication what is called for quite a fair casting in the original article. I do like that mindset than can think in that direction.

If I be a pain, could I ask:

I see the front of the bedplate has been hollowed out between top and bottom plates, is that replicated at the back and underneath at all?

Are the supports on the condenser – for the rear of the cylinders etc etc – fixed by c/s screws into the parts through the condenser walls as well as by the now famed JB Weld? (where would you be without JBW?!)

Why did you make the main bearing caps from two pieces – I assume it is a top and a bottom pieces – was it to save weight?

I think I might well work this up for a future project, noting the drawings in dimensions in red for the scale to be worked in, but might do the drawings at half scale instead of 5/8th scale; however I will see how this pans out all the way through the fittings and fixtures as well as part sizes before deciding what scale. I will do them in imperial not metric as I work in imperial for preference, a thou means more to me, I can visualise them better, than bits of a mm although I will/can work in metric.

Finally, can I ask that you continue to post as many pictures – you are generally very generous in this respect – as you can as you progress the build, close-ups as well as general views, as pictures are worth a thousand words as they say.

Looking forward to the next installment,

Chris

PS: For the record I am also a manual twiddler, no CNC, the mill has a very nice DRO but only a dial gauge on the lathe longitudinal feed.  I too am too old to do this CNC stuff, can't get my head around drawing in 3D never mind whats required for CNC, 2D stuff is still fine for me!

 

 

Edited By ChrisH on 19/02/2021 19:31:08

[PatJParticipant @patj87806]

I seem to recall someone attempting to cast this engine.

If the 3D models are available somewhere (seems like I saw them online), then they could be used to 3D print patterns, from which castings could be made.

This is a great looking engine, and I have admired it for years.

The build for it in this thread is looking very good, and much like castings.

With parts that look that good, who needs castings ?

.

Edited By PatJ on 19/02/2021 20:09:51

[ChrisHParticipant @chrish]

Re my earlier questions, Q3 – I meant material not weight!!

Chris

[Roderick JenkinsParticipant @roderickjenkins93242]

Posted by Ramon Wilson on 19/02/2021 17:34:04:

I knew Rod had CNC but thought he had converted his mill – Rod?

It's one of the Denford/Sherline machines, now converted to Mach 3. It's only a toy. I'm thinking of carving out a new head for the Wyvern out of cast iron with it. Not sure if it's up to the task though. My Sharp mk2 is still manual.

I'm a great admirer of both ways. Different skills but skills none the less.

Stay well,

Rod

[Ramon WilsonParticipant @ramonwilson3]

Hi Rod – well I'd certainly like the facility but don't think it's worth pursuing now. I certainly agree – two differing skill sets but both providing their challenges. Jason has certainly taken the requirements on board and come up with the business for sure. Being able to machine oval spokes on a flywheel is very desirable but not enough to take on board now.

Chris – both sides of the bed plate have been hollowed out – the front is pocketed but the rear was milled along it's length – the addition of the well pump base providing the 'pockets' at the rear.

I originally intended to mill the underside right through and make the webs to drawing but felt that that might be just a bit too weak. I changed the shape underneath and milled it all from solid

The standards are located by pockets on the front side of the condeser. There is one 8BA screw going up from the inside into the central web and two c'sunk 8BA screws in from the front. Theheads of these were not fully home but milled off when the faces were milled square to the base. These screws are more for pulling the standard into place than for anything structural.

I made the bearing caps from two parts for cosmetic reasons and it's much easier to mill the angles on the base part as well as making the radiused ends easier to machine.

I don't want to get drawn into a full build log scenario as it does eat up a lot of time but I will post pics of relevant machining ops where I can.

Pat J – I think the castings were possibly done by an American company?. There is some info on the net but there is nothing currently available as far as I'm aware.

Regards – Tug

[JasonBModerator @jasonb]

Historic Models & Reproductions LLC did a small trial run of castings a few years back. Dennis who owned the company sold it to Jeff a year or so ago but Jeff has some health issues. Can't post a link as both their websites are down/AWOL. Build thread on MEM

For those that can navigate his drawings Julius has also drawn up his version which is more of a fabricated option than cut from solid for example the bed is soldered up from sheet and the cylinder block a multo part fabrivation much like Ramon's D10

[Ramon WilsonParticipant @ramonwilson3]

Ah yes – that's the company Jason – didn't realise there was a build log on MEM, don't visit there so much these days.

Interesting to hear Julius has drawn a version, I wasn't aware that he had but no surprise as he's so prolific. Is it on MEM? and do you have the link for the build on MEM?

[JasonBModerator @jasonb]

Build Thread

Julius' website with the 1923 and 1924 engines

[ChrisHParticipant @chrish]

Jason – thanks for the link, another very interesting thread to read!

Tug – thanks for the detailed reply, you have explained things very well, all is now clear. So many ways to do something and you seem to sort out a very easy and logical path, especially getting around lack of castings – and probably saving shed loads of dosh in the process – as well as providing a satisfying time machining which is after all a major factor in the likes of us doing it in the first place; I have learned a lot from your posts both here and elsewhere.

Never expected for one minute you would do a build log, you've been there, done that and I know you don't want the additional time requirements that would entail; what you are doing now is information enough.

Sorry to hear you don't visit the MEM site much these days, I personally like the way the threads are laid out there, seem clearer to me than here, but thats just my personal preferences!

Funnnily enough, all the time I was at sea I only once saw a marine steam recip engine, in 1964 in a drydock in Cardiff, but never sailed with one. Diesels and steam turbines yes, plenty of, but not steam recip., which is maybe the attraction here!

Chris

[MeunierParticipant @meunier]

Posted by ChrisH on 20/02/2021 11:59:59:

quote….Funnnily enough, all the time I was at sea I only once saw a marine steam recip engine, in 1964 in a drydock in Cardiff, but never sailed with one.
Chris /Quote

Although a land-lubber, I was lucky enough to see one working at close quarters, late 60's to early 70's in Istanbul.
My colleague and I were working there for a few days and found a free afternoon while waiting for replacement electronic kit sent from London. The local office manager recommended a ferry trip from the Golden Horn up the Bosphorus to the mouth of the Black Sea. The ferry called at every landing up the West side and returned via every landing on the East side. Entertainment was provided by the locals using it as a bus service, bringing aboard and later disembarking with goats/sheep/head-carried platters of yoghurt and market-garden produce.
I asked one of the crew if it was possible to visit the engine-room and was duly escorted below and introduced to the Engineer, possibly the first time a passenger had asked to visit. Was amazed, firstly by the heat, and to find a triple-expansion steam engine, supplied with steam by a coke-fired boiler. The engine was in pristine condition, unlike the floor, I suppose boiler firing on the run might be a bit tricky.
Have enjoyed reading this thread, good luck all
DaveD

Edited By Meunier on 20/02/2021 16:25:43

[Dr_GMJNParticipant @dr_gmjn]

This looks like a great project – impressive machining skills. Looking forward to more updates.

[Ramon WilsonParticipant @ramonwilson3]

Thanks Jason, I was surprised to find such a long thread – must have completely missed that one.

Julius has to be complimented on such a tour de force – something there for everyone whatever stage you are at, Some really nice projects there. Personally I like the way he does his drawings – certainly very characteristic. I did have thoughts of his version of Chucks Maudsley Oscillator, using mainly in brass but whether that ever sees light of day remains to be seen.

Chris – don't read anything untoward in not visiting MEM as in the past – just that I find theres only time for one (for me) and I've found the variety on here of far more interest. Never fails to amze me the number of threads covered on a daily basis.

Dave I worked offshore for several years – one of the rigs was a drill ship converted from an ore carrier. It had two four cylinder triple expansion engines and a steam draw works. I was never on board when the vessel moved location so in just over four years never did see the engines running.

Good to see you here Doc – keep an eye out for the JB Weld

Had a near disaster to day – began machining the bottom plate of the cylinder having predrilled three holes on the centre line of the work piece. Having profiled most of one side suddenly dawned that the centre line on the bottom plate, unlike the top, was offset by 3 mm or so. With that gut wrenching feeling that it was a return to start situation I measured it to find I had just .15 mm left to clean up on the offset side – Phewwweeee!

Not much done as the weather has made it 'garden time' – more soon though

Tug

[Ramon WilsonParticipant @ramonwilson3]

Hi Guys,

Despite the weather and garden distraction I have been able to get a bit more done. I have added some more images to the album but here's one of the current state of play as of this evening

I experienced a totally unexpected cutter movement and serious pull in while milling that concave face – a cutter pulling out of an 'Autolock' type chuck. Forty odd years of milling and never seen that before. Perhaps a bit more on that later as it's getting late and tiredness is rapidly setting in.

Just a few more bits to mill though and the head can be assembled

Regards – Tug

[ChrisHParticipant @chrish]

Don't tell me Tug – that concave face will be JB Welded to the LP cylinder!! Nice bit of machining, I like it. Still reading the download, heavy going in parts.

I noticed on the MEM build log of this engine quite a bit of discussion on the crankshaft having the crankpins at 180deg., one could easily put them at 90 deg I think, to make the engine start in any position, but with my luck I would get the 90 deg in the wrong rotation. Which way does the engine rotate do you think?

Re MEM and this site, I find it goes in waves, sometimes there seems loads of interesting stuff going on at once on MEM and sometimes, like now, not much (interesting to me that is), and the same here.

Chris

[Ramon WilsonParticipant @ramonwilson3]

Ha – how did you guess Chris A lot more work to do on that yet but yes that's whats intended.

I have read bits here and there of the text but found the practices describd not relevant to how I had planned so haven't ploughed through it all as such as yet.

I did note from the outset the 180 degree cranks but decided I would do them at 90 degrees – they simply don't look right never mind the potential for stopping on dead centre. Only later did I notice in the text he mentions that option. My plan is a composite affair using Loctite and pinning. The eccentrics will be separate for individual movement.

You raise a good question on what way does a marine engine rotate for forwards motion. With a stationary engine the answer is well known but for a marine engine? Anyone know if there is a defined direction for forwards motion?

Gardening over for the day I'm now off to mill some more of the valve face

Regards – Tug

[JasonBModerator @jasonb]

Would a compound self start if the HP was at approx TDC or BDC as there would be no steam to the LP which would have it's crank in the right position unless a simpling valve were used in which case it's not really "self" starting

[Ramon WilsonParticipant @ramonwilson3]

I'm not sure it would Jason but it definitely wouldn't if the cranks were at 180 so you are potentially right it would not be 'self starting' but near enough – save that one position

Isn't a simpling valve something that would be fitted as standard on a compound/ triple? One is not shown on this drawing but could easily be so

[JasonBModerator @jasonb]

It's certainly something the compound traction engines have both full size and model so you can send a bit of high pressure steam to the LP valve to get things moving so could be worth adding to yours.

[DrDaveParticipant @drdave]

For a compound steam engine, does the angle between the cranks have a significant effect on how well the engine runs? I.e. is there an optimum angle where the exhaust valve for the HP cylinder and the inlet valve for the LP cylinder work together and give more power than a more random timing?

Or am I over-thinking this?

[Ramon WilsonParticipant @ramonwilson3]

Dave

From what I can see in the limited references on marine engines I have there is no reference to cranks at 180 degrees. All engravings and images show them to be at 90 degrees so I can only assume that is the convention.

The previous comment on direction of rotation is still an open one – which cylinder leads the other for instance – again I assume it's the HP to LP in forward motion but don't actually know – I will keep looking for some indication that that has relevance but not able to find anything so far.

Tug

[JasonBModerator @jasonb]

As they are double acting I don't think direction will make much difference unlike an IC engine.

[10ba12baParticipant @10ba12ba]

Posted by Ramon Wilson on 24/02/2021 15:16:35:

You raise a good question on what way does a marine engine rotate for forwards motion. With a stationary engine the answer is well known but for a marine engine? Anyone know if there is a defined direction for forwards motion?

Pg 455 MacGibbon's Marine Engine Knowledge

Ahead rotation is clockwise with a RH propeller

[DrDaveParticipant @drdave]

Tug & Jason: thank you for your replies (regarding the angle between the cranks). There is also the relatively large pipe joining the HP cylinder to the LP cylinder which will help, too. My mind has been put at rest!

In my own defence, I had just been watching a video of Ilmor’s 5-stroke IC engine, where the phasing of the exhaust from HP to inlet of LP cylinders is critical.

Dave

[ChrisHParticipant @chrish]

Buried deep in my shed I have a MacGibbons, or the bible as it was known back in the mists of time when i was doing my tickets. All forgotten now, too long ago. Must check it out seeing as we are now back into the old steam stuff!!

Lets assume the ship has a RH prop then and do the crankshaft accordingly, HP leading the LP seems the most logical.

So good that an innocent question can provoke so much discussion and then an answer – great stuff these forums!

Chris

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