2 videos of the triple and the vertical boiler and the Southworth boiler feed pump working together for the first time. Not perfectly yet, but working.
A beautiful spring morning became blustery, windy, hot yesterday. But I hardly noticed. I was in the workshop making these small steam pipe connectors.
Normally I would buy these fittings, because they are fiddly to make and not very expensive, but I have fitted new rings to the triple expansion engine, and I want to try it out on the vertical boiler. (see the previous post)
one of the tails was not drilled deep enough.
I needed only 2 of these nipple-tail-nut assemblies, but having made a jig to fit the collet chuck it was just as easy to make some extras for future use.
The jig is required because having made one end of the nipple, it must be turned around to make the other end and there is not enough material to hold in the 3 jaw chuck. So the jig holds the workpiece by the first made thread, and the piece is finished by holding it in the collet chuck. The jig will be saved for future use. It has external threads for 5/16″x32 and 3/8″x32, and internal threads for 1/4″x40 and 5/16″x32.
The tiny tails were drilled in 2 stages because there is an internal step, and the outer shape was CNC’d.
Still recovering from The Royal Geelong Show, where my beam engine and the Trevithick dredger engine ran for ~8 hours per day for 4 days, and required almost constant supervision. I was very pleased that they did so without a problem.
For future exhibitions I would like to also run the triple expansion steam engine using the vertical boiler, for which I recently made the Southworth boiler feed pump. And there are occasions where I might run the triple and the beam engine together from the vertical boiler. That arrangement will occupy a fair bit of bench space, and in this post I am considering options for the arrangement.
But first, I needed a steam outlet manifold to handle multiple engines, simultaneously, and hopefully to avoid a big tangle of pipes. Here is the manifold.
The manifold has 6 x ¼” outlets and one 3/8″ outlet.
Option one lines up the boiler and engine like this….
Option two is more compact, but ?less appealing. Pics following..
The lump of wood under the engine is temporary, just to give an idea of the heights.
OK, this post is just an excuse to show some pics. I have decided to go with option one. It is closer to the appearance if the boiler and engine were actually in a boat, and also will make it easier to add the beam engine to the right of the boiler if/when I run the two engines simultaneously.
And I doubt that I will be able to avoid a jumble of pipework. The triple has 6 pipes attached, the boiler has more, then there is the beam engine. And, I will need a water container from which to feed the boiler. That will be located behind the boiler. Still considering whether it should be a squarish box on a stand like the railway water towers, or a cylinder on a low stand. Any thoughts?
Firstly, the book review. It is short, because I did not enjoy it. Not that it is badly written, or poorly researched. But it is really shocking.
EMPERORS OF ROME. THE MONSTERS. by PAUL CHRYSTAL
From Tiberius to Theodora. AD 145-548
This book is one of the series published by Pen & Sword on the architects of terror. Other volumes include Al-Qaeda, The Armenian Genocide, Bloody Mary, Einsatzgruppen, to give you an idea of the scope of the series.
Now that I have finished with the book, I am examining my own motives in choosing it. I have read many books about ancient Rome, and find the era fascinating; the personalities, the reasons for the rise and fall of the empire, why the military was so spectacularly successful etc etc.
But to be truthful, I did not actually finish the book. I had a similar reaction when I read about the Nazis and the concentration camps. Just too horrible to contemplate. And I closed it after reading about half. And will not reopen it.
Paul Chrystal is a well-respected author who has written many books about ancient Rome. He states an aim to use primary sources, and to balance the horror with the mitigating aspects of the monsters. The book is 127 pages long, and it covers 10 emperors, so there is not a lot of space to give a balanced view. Mostly, despite its aims, the book is about rape, murder, treachery, nasty and insane men and women with absolute power doing whatever they felt like doing.
And to be realistic, even the “good” emperors started wars, executed rivals, instigated massacres and mass maimings. That was the way things happened in ancient Rome. And twentieth century Germany, China, Cambodia etc etc.
So, if you enjoy seemingly endless descriptions of sadistic torture, rape and mass murders, with many illustrations, this book might be for you.
Not for this this reviewer though.
John V.
Now, back to getting enough heat into the 1:8 Trevithick Dredger Engine.
I have made a grate to place into the firebox, and which will replace the gas burner, which has proved to be inadequate, despite many, many experiments with improving it. So here is the grate.
Putting a rather unpleasant book to good use.
The holes in the grate are tapered, with the smallest part of the holes uppermost. The fold at the back is to prevent coal being pushed off. The taper is to prevent clogging the holes with clinker, and possibly to improve the velocity of air flow through the fire.
And how did I drill so many small holes so neatly?
CNC of course. Took about 45 minutes.
But after that I had a conversation with Stuart Tankard. He reckons that I will do no better with coal than I have with propane to date. Hmmm. Might give it a go anyway.
Stuart’s suggestion is to try one of these….
It is 50mm diameter, has a large jet (0.81mm diameter) and has a fearsome flame. Looks more like a silver soldering torch. If I use it I might get a flame coming out of the chimney. Hope that it does not melt the silver solder.
This is a video showing how I performed the hydrostatic test on the boiler.
The engine is currently being made, but not at the time of the video.
The test is to hold water at double the working pressure of the boiler, for 20-30 minutes, checking for bulging or distortion of any of the components, and any significant leaks. Any leaks would need to be fixed, but for the boiler certification, as long as the pressure can be maintained for the duration of test, that is OK.
The working pressure of this boiler will be 50psi, but the minimum pressure in the AMBSC code is 60psi, so the hydrostatic test will be done at 120psi. As you will see in the video, the pressure reached 140psi at times.
In fact, the AMBSC code is formulated in terms of materials and design to cope with 8 times the working pressure, so the safety margin is generous.
The video is taken over 20 minutes. I ran the actual test for over an hour.
I am afraid that my very messy bench and workshop are evident in the video. No apologies. That is just the way that I work.
The Tasmanian Oak lagging looked too pale white to my eyes. With use, steam, oil, dust, water, workshop grime and sunlight, it would have gradually acquired a well-used patina, but I prefer instant gratification.
So after consulting my resident wood finish, artist, architect, expert, (SWMBO), I applied some wood-stain.
Too orange, too patchy, she said. And the white in the joins looked wrong.
Too orange, too patchy, and too much white showing. “Put on some black boot polish” she directed.
So I did as I was told.
With a boot polish brush…
—and a toothbrush…
… hmmmm. I better clean her toothbrush before putting it back….
…(acknowledgments to Tubal Cain for using his old gag…)
That’s the look I was wanting.
Now just waiting for the brass bands to arrive.
Ben De Gabriel from EJ Winter, Sydney, had sent me a remnant piece of banding to try, in my last consignment of parts from him. It was perfect, but not enough for the 5 bands which I require. So I rang him. He thought that was the last of his stock of that particular size but he would check and let me know. Sure enough, he returned the call, and he had found a couple more bits, and they would be just enough. Old stock, a bit shop-soiled he said. So I could have it for nothing!
Readers who have been with me for some time will know that I have bought 3 sets of engine castings and plans from EJ Winter. The Bolton 7 horizontal Mill engine, the Bolton 12 Beam engine, and the Bolton 9 triple expansion engine. A bit of very interesting news is that Ben is planning a new set of castings for the triple, using the lost wax casting technique, which gives a finish which should require machining on the mating surfaces only. That sounds so good that I am almost tempted to make another triple. Almost. Some months until availability though. (Hope that you don’t mind my premature announcement Ben.)
Lagging. As in boiler insulation, not as in failing to keep up. I have been working on the boiler for about 3 months, so I am actually happy with the progress. And more than happy to have passed certification!
I decided to apply wooden lagging strips for the appearance and for ease of handling, rather than any minimal improvement in performance of the boiler.
After use, the boiler shell is too uncomfortably hot to handle, so there is a waiting time of 30 minutes or so to allow it to cool. I am hoping that wooden lagging will reduce the waiting.
And wooden lagging will hide the splodges of silver solder around each boss and join. And it looks the part IMO.
But how to attach it? None of my books mentioned any method. I presumed that the brass strips are the main method, and that is certainly so, on full-size boilers. Then I found a short video on YouTube by Keith Appleton and I decided to copy his method.
The method uses Super Glue as a temporary securing method while positioning the strips, then applying brass strips to hold the wooden strips in place long term. The boiler heat and expansion-contraction will result in the glue bond being temporary, and if the wood strips have to be removed later, for any reason, that will be possible. It also means that an insulating blanket cannot be inserted between the copper shell and the wooden strips, but I was not planning on using a blanket, so not a problem.
The strips are 3x8x265mm. I chose Tasmanian Oak which is actually an ash, because it is hard, fine grained, and I had some in old floor boards. I cut the pieces to length a bit oversize, then ripped them to size on the bandsaw. It is difficult to avoid fingers being close to the blade with small pieces like this, so I used a push stick. I needed 65 pieces. The blade teeth are a bit too coarse for this job, but I was too lazy to change it for a finer one. Note the saw blade guide. I did not like the one which was provided by Metabo, so I made that one. Works well!
Then I used a belt sander to remove most of the sawing marks. The resulting thicknesses varied from 2.8 to 3.4mm but I hope that variation will not matter.
Some hand sanding to remove wood fur.
Hope that this will be enough pieces!
The boiler feels out of place in all this woodworking rubbish.
SWMBO was away, so I set up on the kitchen table. Here deciding on the final length of the strips.
Each piece is cut to length, then fitted into position. Shaping the wood to fit around bosses and fittings is done with a small sanding drum in the Dremel. It is a slow process. Then each piece is glued into place, and held with rubber bands.
It has taken about 4 hours to apply about 1/3 of the strips. The Baileys was to keep me in an appropriate mindset. I am looking at the slightly ragged top and bottom edge in the photo. Looks a bit rustic and authentic, or just rough? The wood will be darkened after oiling, and possibly staining. And Tasmanian Oak darkens with exposure to light.
That was yesterday. Today I hope to complete this job, but SWMBO is home, and not appreciating the dust and mess, so I am exiled to the outside.
I have realised that to secure all of the wooden pieces I will require 5 brass bands. I do not want it to look too brassy, so I am ordering narrower strips than the 6mm material which I had previously bought. I think that 4.75mm will be about right.
Today I put water in the boiler, about half way up the sight glass, hooked up the gas, and lit the flame. Very nervously. What if it blows up? What if one of the soldered bosses blows out? What if the safety valve does not work?
Admittedly, before that I had pressurised the boiler with water, with the fittings, to 150psi, and without the fittings to 200psi, and that seemed OK except for a leak in the sight glass. But even so, a steam test has a lot more at stake.
I had set the safety valve to 100 psi with water, but steam is a quantum leap in risk.
This is what it currently looks like.
The burner works OK, but I am expecting that it can be improved.
It took 5 minutes to get to 25psi, 6″ to 50psi, 7″ to 75psi, and 9″ to 100psi. At that point the pop safety valve released, suddenly and loudly, giving me quite a start. For a few psi under 100psi it had been releasing small amounts of steam, but the “pop”, in the confines of my workshop, was really impressive.
And a video of the boiler at 100psi. Sorry about the commentary. Must brush up on my video skills.
I have learned a bit about pressure gauges from Frank, who used to manufacture them, and from Stuart, who made a 5″ vertical boiler which was the inspiration for my 6″ build.
For one thing, pressure gauges become less accurate as they become hotter, so steam should not be allowed into the Bourdon tube. Which means that there should be water in the line between the steam and the gauge. That can be managed with a pig’s tail coil of copper tube, or a water reservoir, which is what I made.
For another thing, gauges have varying accuracy, and I am fortunate in having a friend who has calibration equipment, so I can obtain information about the degree of accuracy of my selection of British and Chinese gauges.
Then there is the aesthetic appearance of the gauges. A matter of taste, but I really like the older “Smiths” made in UK gauge.
So this is what I ended up installing. I might change my mind later, but for the moment…..
These are the gauge components. The Smiths gauge itself (needs a 100 psi red line), the brass support made today, and the copper tube which provides the water barrier.
I like it! Hope that you agree. Still need that shed tidy-up.
The boiler will most often be fired on gas, but it is being made so that it can also use coal-wood.
So the base needs to cope with ash from coal or wood, and also have adequate clearance to fit a gas (propane) burner. And to look OK. And to be not too heavy to carry.
This is what I have come up with.
Two plates of 6mm aluminium, separated by brass pillars. It should polish up nicely.
This is the first burning test. Fail! Too much yellow. Not enough blue. Back to the drawing board. Propane – air mix is not correct.
So I increased the jet diameter……
The flame size increased, but the mix did not improve. A work in progress. Another jet change, and an adjustable regulator to be tried next.
To do something positive, I made a firedoor latch and catch. Some CNC and filing.
Not finished, but going OK.
The doors on this boiler have consumed more time and energy than I expected.
Partly because the firedoor has a vent, has a heat shield, is oval shaped, and is mounted on a curved surface which will get very hot in use.
It is still not quite finished, needing a catch and a latch. There is a spring which pushes the vent against the door. And a heat shield which needed a few shaping processes to make sure that it did not foul the firehole. The heatshield is supposed to be stainless steel, but the copper cutout left over from when the firehole was cut in the wrapper, seemed ideal for the job. The central shaft is stainless steel, threaded M4 at back and M3 through the door.
I intend to use propane as the main fuel for the boiler, but I have constructed the firebox so it could use coal as an alternative. This is the ash pan opening. Constructed from 1.4mm brass, and silver soldering the join. Pretty neat hey! I have made the door and hinges, and will hang the door next session. I will replace those cap screws with something more suitable.
The hinges are quite small. 3mm wide, and when trimmed will be about 18mm long. To make them I drilled a 1.5mm hole in a piece of brass rod, silver soldered the rod to some 1.3mm sheet brass, then bandsawed- cut the piece into separate hinges. Since that pic was taken I have milled the width to 3mm, and trimmed the lengths. I dropped one hinge, and spent a fruitless hour trying to find it. Fortunately I had made a spare, but I cannot aford to lose another. The hinges will be riveted to the door and the ashpan surround.
Some more progress on the 6″ vertical boiler. Not much to show, but here it is.
Actually, I have been wondering whether to continue with this blog as a “what I have done today” type diary, or whether to post less often, but when a significant milestone has been passed. Your feedback would be welcome on this decision.
The superheater is a copper item, which steam passes through, and is located in or just above the furnace. As a result the steam becomes hotter and drier and more energetic before it is passed through the engine or whatever it is being used for.
This is a lump of copper, 10mm thick which I have cut off a bar which I had in stock. It will be machined into the superheater spearhead.
The copper spearheads machines into shape. Copper is soft, but it grabs the cutters. Not nice to machine. Expert Stuart said that I should have used lubricant. Next time.
The sperheads are bronze brazed to copper pipes, but the difficult bit was bending the 1/4″ copper pipe to fit.
The spearhead is bronze brazed to the copper pipe. Tricky, but seemed to go OK. Don’t know yet whether the bronze join is steam tight.
The tricky bit is the 2 x 90º bends, really close to each other. Does anyone have any good method for doing this? I ended up with this result, but it is not pretty, and I am sure there must be a better method for creating the bends.
The silver soldered joins are yet to be done into the brass fittings shown. I ran out of time in the workshop.
This is getting exciting! I am not too far off firing up this boiler!
Then a visit to the boiler inspector.
So what is the big deal?
Well for a start, this is a big deal financially. The materials to be joined are expensive, and some are difficult to obtain.
And the silver solder itself is expensive. We ended up using 4 sticks of 45% silver solder, and an unknown quantity of oxygen, acetylene and propane.
And the end result will be inspected by an expert boiler inspector, and if it is substandard, it will be rejected. No argument.
So yeah, it was a big deal. Look at the pics. A few friends called in to watch and help. It was a cold wet winter day, and I had the workshop wood heater working to keep the troops happy.
I used steel wool to expose the elemental copper.
Me applying flux. Note the silver solder rings which were made on the lathe. Don’t ask where the brush originated.
The firebox wrapper was placed on the aerated concreted form to keep the tubeplate level, and allow the tubes to penetrate exactly 2mm. The tube ends were fluxed, and silver solder rings placed into the join.
The 44 fluxed firetubes with their rings of silver solder are in place. The top tube plate will not be brazed at this time. It is there to keep the firetubes in the correct position. The firebox tubeplate is also fluxed and sitting in position on its Hebel block.
Me on the left with the propane weed flamer applying gross heat, Stuart with oxyacetylene applying local heat and silver solder, and Swen cheering. Brendan is the photographer, trying not to get burnt.
We probably should have reshaped the forge to reflect the heat more efficiently.
When the brazing seemed to be finished, the work was allowed to cool to 200c, then quenched in water then a 15″ soak in 20% sulphuric acid to remove any remaining flux, then a further water soak to remove any acid. Yes, the top plate is upside down. Yes, it will be reversed eventually.
Inspection from inside the firebox. Most firetubes have taken the silver solder properly, but a few of the inner circle and the flue require a second application. The brazing heat looks to have been inadequate near the centre, probably due to the density of the firetubes.
So, not a perfect result, but not bad for a beginner. Stuart opined that the job would have been better if my silver solder was the older, (more dangerous) but more runny type which contained cadmium.
OK. My non machinist readers will have no idea what I am talking about. And I suspect that my machinist readers wont either.
I need some precisely machined and measured blocks to set up the soldering for the boiler. I want them to not suck up my soldering heat (so no metal), and to not stick to my silver solder (so not steel, copper, etc).
How about concrete? More specifically, aerated concrete. Hebel.
Look at the pics…… I need a cylinder, about 100mm high and 110mm diameter, which will not absorb heat and not stick to silver solder.
This is a 600x400x75mm Hebel block. Cost $AUD4.60. It is part of my forge, but will be replaced easily.
Marked out the bit I want.
So I cut it on the bandsaw. It is aerated concrete. Hebel.
Cuts quickly and easily. Probably not good for the blade. But we will see.
How accurate is the thickness?? Pretty amazing IMO. within 0.1mm. The second measurment is after a quick touch up with emery paper on a flat plate.
And this is the first setup, ready for soldering. Watch this space. soldering in 2 days.
Some more progress over the last 2 days.
The chimney flare sitting in its intended position. The attachments at the smokebox are completed.
The smokebox tube plate, waiting for its firetubes. The bronze fittings are the safety valve and its standard on the left, and the main steam outlet standard on the right, sitting in position.
My workbench becomes increasingly cluttered as a job progresses.
Silver brazing is the next step. There will be 2 major soldering sessions, with boiler inspections after each one. I will enlist some extra hands and expertise for the soldering. (Stuart, I hope that you are reading this.)
I was relieved from duty with the ankle biters for a few hours today, when my wife took them to the local animal sanctuary. They petted a Tree Python (OMG!), and a Koala, and were entertained by the talking Sulphur Crested Cockatoos, one of which is aged 91 years!
Making the most of my temporary freedom I visited the workshop. Soldered the chimney support to the smoke box roof, and made a chimney flare. It probably has a more technical name, but when you see it, you will realise where it goes.
This was my first effort at making a boiler end plate. It was OK, but a lot of my hammer blows left dents which looked pretty ordinary.
I tried to improve the appearance by polishing, but that just accentuated the dents.
The boiler inspector passed it, but I coud see that he was not too impressed. And neither was I, so I made another one. This time I made male and female wooden forms, annealed the copper disk and pressed the domed shape. Then re-annealed and hammered out the flanges.
It was worth the extra effort No?
I will keep the reject part. Might be useful for something, and will remind me to be more careful.
After all of the careful flange forming I was careful to not screw up the firetube perforations in the boiler end plates. At times like this it is great to have a CNC mill/drill.
The wooden form is useful as a clamping aid.
No major stuff ups (or should it be “stuffs up”?). And I am not pointing out the small ones. I was unsure in the firebox plate which side to chamfer. Will I silver solder the top side or the bottom side? Eventually I decided that I would solder between the firetubes rather than the underside. Still unsure whether that was the best decision.
The “ligaments” (the metal between the holes) must not be less than 3mm. The minimum in these plates is 3.5mm. The holes are chamfered to make the silver soldering process easier. The extra hole in the top plate is to install the bronze bush for the attachment of the wet header.
The first part to be made for the Trevithick dredger engine is the domed end of the boiler. It is formed from copper plate which is 3mm thick. first a circle is marked out, then bandsawn from the copper plate.
I decided to make a wooden form. Fortunately I have a CNC lathe (see earlier posts about the CNC conversion of a manual lathe), so drawing the profile and generating the G code using Ezilathe was, well, easy.
CNC’ing the wooden form for the boiler end plate. The roughing steps. Carbide tip which has been sharpened to a cutting edge, suitable for wood.
This is the final roughing cut, and starting the finishing cut.
CNC turning. Light sanding required to remove the fur. The wood is European oak. Central hole for a locating pin.
The oak form was attached to a red gum block which was held in a 6″ vise. I have already commenced shaping the copper disk here. The copper is cramped to the oak form after annealing, and gradually hammered to shape. Tapped rather than hammering.
My “forge” is a few fire bricks in a steel shell, and a roof of steel to help retain the heat. The torch is fuelled with propane. It was originally a weed flamer, used to burn serrated tussock.
Red heat was achieved in 90 seconds. This is 600 degrees centigrade. copper melts at 1084c, so there is a good safe margin. I quenched to cool, for speed.
This welder’s clamp proved to be the most effective method of holding the copper disk to the form. I fitted copper and brass heads to the tapping hammer to minimise the chance of “bruising” the copper.
Progress
About 10-12 heating-hammering cycles in 1.5 hours to get to this stage.
Getting close. I will finish it tomorrow. Might wash up before cooking dinner.
One aspect of our weekly GSMEE meetings (Geelong Society of Model and Experimental Engineers) is that I learn something new at every meeeting. The exposure to new information is not too surprising considering that our group has members who are or were a machinery designer, mechanical engineer, CNC operator, marine engineer, aircraft mechanic, a quarry operator, gun enthusiasts, a fireman and various other areas of expertise. Even a bee keeper. And even a retired gynaecologist.
Recently Neil brought in a boiler which was assembled but not yet soldered. And it was held together with spring loaded clamps the like of which I had never before seen. Some other members were also very interested in the clamps, which are, apparently, extensively used in aircraft panel assembly and repair, and also in car body work repairs.
Neil’s boiler end plates, clamped together.
The clamps are called CLEKOS or CLECOS. They are easily applied and removed and are reusable. They are used for temporary joining of materials to facilitate marking, drilling, riveting, soldering, welding or gluing. Exciting to me because I can see many applications in model engineering and wooden toy making.
The Clecos come in a variety of sizes and configurations.
This Cleco requires a 1/8″ hole, and will join materials up to 1/2″ total thickness. This type joins 2 or more pieces of material which have a hole drilled as small as 2.5mm up to 5mm. The range of hole sizes may be larger than I am aware. Only one face of the materials needs to be accessible, so the Cleco can be used to fasten material to a closed container such as a boiler. It is spring loaded and requires a tool to apply and remove it. Application and removal is very quick. Any materials which will accept a drilled hole can be used- metal, wood, cardboard. It would not work with easily compressed material such as foam rubber. The application pliers are available on Ebay and are inexpensive.
This spring loaded Cleco looks particularly interesting. The clamps are small, have clamping thickness of 20mm and a reach of 1/2″ to 1″. Again, they are not expensive ($AUD7-11), and very quick to apply and remove. Surprisingly powerful grip would be quite adequate for gluing or riveting or soldering.
Some Clecos do not require the application pliers but use a wing nut.
And others use a hex nut. Anyone know why there is a copper surface coating?
The Clecos are surpisingly inexpensive. On Ebay I have seen the spring loaded fasteners as cheap as $AUD1 each, and the pliers at $AUD15. I bought a kit comprising pliers and 20 fasteners for $AUD49. Ebay UK has the best selection and many have free postage. The range on US sites is good, but postage costs assigned by Ebay are astronomical.
(A reader has commented……
johnsmachines 