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machines which I have made, am making, or intend to make, and some other stuff. If you find this site interesting, please leave a comment.

Category: boiler

Hydrostatic Trevithick Boiler Test

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.

 

Back to the Trevithick Dredger Engine

The 6″ vertical boiler is virtually completed.  Well, actually, I still have to make a Duplex steam pump, fit a steam injector, make a steam delivery manifold, paint some bits….  but yeah, emotionally, for me it is finished.   I will get back to those bits as the mood takes me.

So I have picked up the bits of the Trevithick steam dredger engine.  I will concentrate on the boiler, so I can get the AMBSC certification, then take a leisurely approach to the engine.  You know, 2 weeks to the boiler certification then another 4 weeks to finish the engine.  Or something like that.

 

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As you can see, I have redesigned the inspection hatch, and made the new version.  This is still not quite authentic, but it is much closer to the London Science Museum example.  The inspection hatch will be permanently closed, silver soldered shut.   And the wording reflects the fact that this is a model.  The model hatch is circular, whereas the LSE example is something between a circle and an ellipse.   Trouble is that we do not know what is original Trevithick and what was altered in 1870.   So I do not feel too guilty that I am guessing.

 

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Sorry about the poor focus.  I will retake this shot later.  You can read my new AMBSC ID number.  I do feel presumptuous writing my name the same size as Trevithick.

 

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I have marked the boiler perforations and will drill the holes then make the bronze bushes.

 

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A hi res photo of the dredger engine in the LSM.  You can see that the inspection hatch is something between a circle and an ellipse, not a rectangle. And that firedoor hinge is definitely sus.

 

 

 

 

 

How does a 6″ vertical boiler enhance house decorating?

When I was making the 6″ vertical boiler, SWMBO commented, “you needn’t think that is staying in the house!”

Well, she did say,  after the boiler bands went on “Hmm.  That looks quite interesting”.

So I took that as my invitation to put it somewhere….  in the house….

 

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This desk is just inside the front door.  The boiler sort of melts into the background, don’t you agree?   SWMBO has not spotted it , yet.

 

6″ Boiler Lagging -3, and back to the Dredger Engine.

The brass bands which secure the wooden lagging strips were installed.  5 bands were required to make sure that every piece of wood is held once the glue lets go.  The bands are only 4.75mm wide.   The bolts which apply the tension pass through small brass blocks which are silver soldered onto the ends of the strips.  (thanks Ben De Gabriel of EJ Winter for that tip!  And for the band material!)

 

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The boiler sitting on our kitchen table.  I will eventually paint the ashpit door assembly and angle plate at the base.

 

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The setup for holding the small blocks in position during silver soldering.  In order to not close up the gap between the small block and the brass strap, I centre punched the blocks, raising small dimples, which produced a thou or two of separation between the parts, allowing the molten silver solder to flow.  That silver solder wire is 0.5mm diameter. 

 

 

And back to the Trevithick Dredger Engine….

 

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The redesigned inspection hatch.  The bronze rectangular bit plugs the hole in the end plate.   I have plugged the unwanted 14 holes in the end plate, using stainless steel threaded rod.   And metal worker’s hands, cut, dirty, dry thick skin (SWMBO “don’t come near me!”).

 

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Four of the plugged holes around the firebox opening, 10 more under the inspection hatch (hidden), and the inspection hatch.  I will make the inspection hatch a little bit smaller.  It will be decorative, permanently attached and unable to be opened.  The dredger engine in the London Science Museum has the manufacturer’s name cast into the plate.  I am contemplating just inserting Richard Trevithick’s name and the date the first high pressure engine was made (1806).  There will need to be a separate area on the boiler wrapper the AMBSC identification.

 

 

 

 

Boiler Lagging -2

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.

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So after consulting my resident wood finish, artist, architect, expert, (SWMBO), I applied some wood-stain.

 

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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.

 

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With a boot polish brush…

 

 

 

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—and a toothbrush…

 

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… hmmmm.   I better clean her toothbrush before putting it back….

…(acknowledgments to Tubal Cain for using his old gag…)

 

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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.)

 

 

 

6″ Boiler. Lagging.

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.

 

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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!

 

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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.

 

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Some hand sanding to remove wood fur.

 

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Hope that this will be enough pieces!

 

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The boiler feels out of place in all this woodworking rubbish.

 

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SWMBO was away, so I set up on the kitchen table.  Here deciding on the final length of the strips.

 

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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.

 

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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.

 

 

 

 

 

 

 

 

VR-18-18

VR-18-18 Stands for Victoria, Geelong Society of Model and Experimental Engineers, 2018, 18th registered boiler for the club.

So this morning I fired up the boiler with the boiler inspector closely watching.  The gas was turned to maximum, and the water was showing full.

Steam appeared about 10 minutes later and the Sandberg safety valve started popping at 100 psi. Every couple of minutes the safety valve released and the pressure remained in the 97-100 psi range.  This went on for about 20-30 minutes.  All to the satisfaction of the inspector.

He was happy with the standard of the build, the pressure test, the accumulation test, and that all requirements had been met.

The boiler is now certified for 4 years.  There has been a change in protocol about which I was unaware.  The previous certification rule was for 12 months only, and retesting was required for a further 3 years.  So this new rule is much less time consuming for me and the inspector.  He is happy that before the next testing I will have a steam pump and a steam injector installed.

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I was so delighted with the result that I treated myself to a trip to the non ferrous metal supplier, and bought a selection of hex brass stock for the workshop.  When I returned to the workshop there were still a few hours of daylight, so I spent the time making the new inspection hatch for the Trevithick dredger engine.  Not quite finished, so no pics yet.

The next step for the boiler is to make and attach the wood lagging and to put on some paint.

A steam driven water pump, and a whistle.

Boilers, whether full size or model, get through substantial volumes of water.  When my 6″ vertical boiler is working hard, so is the water pump, to replenish the water which is turned to steam.

At present, the water pump is a manual pump, and it needs to be operated almost continually when the boiler is steaming hard.

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I am not sure whether operating the hand pump (lower right), or the propane burner, consumes more energy.

So it was with great interest that I viewed the steam pump in operation which was built by Stuart Tankard, at last night’s meeting of GSMEE.  I have plans and castings for the same unit, and expect to make it later this year.  It is a Worthington type pump, and the castings and plans were supplied by Southworth Engines.

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Stuart’s latest.

 

In this video, for the demonstration, the pump is running on very low pressure compressed air.  The larger cylinders are the steam powered driving cylinders, and the smaller ones are the water pumps.  So whatever the pressure of the steam, the water pressure will be greater, and able to be pumped into the boiler.

And finally, I bought a steam whistle.  It was supplied by Microcosm.engine from China and it was very reasonably priced. ($US39).  I have not tested it yet, but it came highly recommended by Keith Appleton.  It is certainly very nicely made.  I screwed it onto the boiler as a bit of bling because I showed my boiler progress at last night’s meeting of GSMEE.

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Almost ready for the boiler inspector.

Almost ready for the boiler inspector!

It feels like the countdown to the finals medical exams!

So today, I drilled the gas jet from 0.22mm to 0.3mm.   A drill bit to drill 0.3mm, is, at least to my eyes, barely visible.  It is finer than the finest sewing needle.  If I pick up a 0.3mm drill bit I can not feel it.  It has no discernable weight.

So this is how I increased the jet size from 0.22 to 0.3mm.

Oops!  I forgot to take a photo.  I bought a set of micro drills from Jaycar, and the smallest bit was 0.3mm.  So I mounted it in the Dremel, and ran it at 10,000 rpm.   for a vise I used my fingers.  The drill went straight through the millimeter or so of brass with no detectable resistance.   Managed to miss my fingers.

0.22mm to 0.3mm diameter is almost a doubling in area of the jet orifice, so I tested the flame.  It was (not surprisingly) much bigger!   And still a good blue colour, with minimal yellow.  So I stopped there.   I also installed an adjustable propane regulator Huib.

Then I made an angle piece to secure the boiler to its baseplate.

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I needed a non rusting disk, 165mm diameter, with a 152mm hole.  The disk was 2mm thick.  So I roughly bandsawed it out in 2mm brass sheet, then set it up in the lathe as shown above.  Turned the outside diameter.  The brass sheet is held just with pressure between the headstock and the tailstock, and the disks of wood.

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Then I held the disk in the 3 jaw chuck and used a parting tool to cut out a disk to form the middle.  The waste middle came out with a bang.  I was careful to stand to the side, anticipating the decapitating scythe.   And I was not disappointed.  I did have to check that my head was still attached.

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Again, I was so involved with the machining that I forgot to take pics.  The vertical part of the angle piece is a slice of copper tube which I had reserved.  It was silver soldered to the brass  disk, then screwed to the boiler wrapper.   Some further fitting, and it ended up like this.

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The hand pump has been mounted.  yet to be connected.  A steam driven water pump will eventually occupy the spare space.  And just to make quite sure that there is enough water pumping capacity I will also be installing an injector.

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And another nice bit of bling (John).  This globe valve was made by Stuart Tankard.  I have borrowed it, pending me making one of my own.

6″ Vertical Boiler- the ID plate

Last task before the boiler inspector.  The unique identifier.  In my case the VR-18-18 code is stamped on the boiler in a safe location, or engraved onto a plaque which is silver soldered to the boiler shell.

I chose the latter method.  And used the opportunity to put my name and date on it.

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CNC’d the info onto a brass plate, and bent it into shape,  I use V-Carve Pro for engraving jobs. 

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Then silver soldered it into position.   In this case I used a lower temperature silver solder… “StayBrite”, so I did not risk melting the previous joins.

 

6″ Boiler. First Steaming.

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.

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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.

 

 

Boiler. The Pressure Gauge.

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…..

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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.

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I like it!  Hope that you agree.  Still need that shed tidy-up.

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Boiler flame fixed, and firedoor progress

The propane burner was fixed by RTFM.  There I noted that the burner was intended to be run straight off the bottle with no regulator.

I replaced the jet with one of the original size, and connected the supply hose directly to the bottle without a regulator.  Resulting in a beautiful clear blue flame.  Which did not show up well on a photo so you will just have to take my word for that.  I intend to experiment with slightly larger jet openings to fine tune it.

Then to finish the workshop session I made some fiddly little bits for the fire door.  “Bling” as my friend John would characterise it.

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You might notice the latch limiter, and the handles on the latch and the vent.  M2 screws.  All of those bits work well.  Some finish filing still to be done.

Boiler stand, gas fire, and firedoor latch/catch.

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.

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Two plates of 6mm aluminium, separated by brass pillars.  It should polish up nicely.

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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.

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Not finished, but going OK.

 

Just how strong is a silver soldered join?

I bought some 6mm x 0.7mm brass strip to hold on wooden lagging on my 6″ vertical boiler.   Trouble was that I could find suppliers who had the strips only in 300mm (12″) lengths.  So I decided to join 2 of the strips to provide the 450mm lengths that I need.

I have made band saw blades with silver solder, quite succesfully, but the ends were scarfed so the join was over a 5mm or so length of the blade.

I wondered whether I could butt join the brass strips with silver solder, and if so, whether the join would be adequately strong.

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So here are the brass strips end to end, fluxed and weighed down so they do not move.

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And here is the silver soldered join.  Not particularly neat, but OK for the purposes of the test.

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The other side.  As I said, not particularly neat. And I did not even bother with an acid soak.

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So I drilled a hole in the end of the joined strips, and wired on a hefty weight.  The top end was held in the vise.   Seemed OK so I increased the weights.

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Looking down the strip from the vise.

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By this stage I was standing back, expecting the soldered join to give way.  But it did not.  Hmm.   Must do a tidy up soon.

 

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21 kg, 46.3lbs.

At this point I stopped adding weights.  I think that the soldered join should hold the wooden strips to my model boiler!

Are you impressed?  I am.

 

 

 

A new skill- riveting stuff

And I don’t mean pop riveting.  I used some solid copper rivets on the vertical boiler today.  I tried to avoid them, hoping to use small bolts and nuts instead, or even soldering,  but ended up doing it properly and using solid copper rivets.

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They do look the part.  No?  This is the ash pan door.

The copper rivets are already annealed.  You need an anvil with a depression which is the same same shape and size as the rivet head, a hammer, holes drilled and a method of cutting the rivets to length.

I secured the anvil in the vise.  The anvil was a bit of steel rod into which I bored a hemispherical depression with a ball nose end mill.  I super glued the boiler parts together, then drilled them.

Then hand held the parts containing the rivet, used side cutters to cut the rivet to length so that about one diameter of rivet was protruding, placet the rivet head onto the anvil, then gave the cut end a few taps with the hammer, to pean it over and secure it.  Easy as!

Those are the first solid rivets I have used.   Ever.

Then I silver soldered the handle in place.

The next job was a bit trickier.  I made some holes in the smoke box lid to let the safety valve and dry steam header poke through.  I tried drilling them initially, holding the lid with my hand, but the inevitable happened….   the drill bit grabbed, spun the work around, threw it and left a row of little dents on the copper surface.  I had been contemplating polishing the copper or painting it.   I guess this little accident means that I will be painting it.

So next I held the lid on the wooden form which I had used to make it, and held the form in the drill vise.  No more grabbing and throwing, but it was a bit tense.  I gradually worked up the drill sizes, and when it became close to the desired measurement, I filed the last bits.

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Those taps are vertical.  They appear to diverge because the iphone has a wide angle lens.  2 penetrations made.  One more to go.

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6″ Vertical Boiler. Finishing the firedoor

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.

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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.

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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.

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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.

Hanging a door on a boiler.

After yesterday’s disaster, I realised that I could not fix the door and vent that I had spent so many hours making.  The vent holes and the vent itself were too big for the opening into the boiler.  So I had to totally redesign and remake them.

But you know what?  When you make something a second time, you have done it before. And the second making is MUCH faster.

So I remade the firebox door and the vent control grill.  Then I made another hinge.  And I attached them to the boiler.  And you know what else….   I broke another f*****g 1.5mm drill bit in the hinge…. again.  But it is OK.   I have made that mistake only twice on this job, so I have got two more goes before I slit my wrists.

As for the suggestion that I use EDM to remove the broken drill piece, I really doubt that would work on a 1.5mm drill.  But maybe…..

But the broken drill bit was in both the door and the hinge.  So I just left it there, and it can become half of the hinge pin, permanently.

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The top hinge pin is the broken drill bit.  The bottom half is the 2mm cap screw which I managed to thread in place.  The photo is upsidedown.  This is not yet finished.  I still need to make and install a baffle for the door.  And the ugly soldering splodge will disappear under the paint or the wooden slat lagging….  haven’t decided yet. 

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The door is eliptical.  And it will be painted so I have not fussed too much about finish.  This photo needs to rotate 90º.

 

Two steps forward one step back again!

I had a whole day to myself, in the workshop.  SWMBO was happy painting or something, and the kids did not need us to baby sit the grandchildren.  So, let’s make the 6″ boiler fire door and ash pan door.

But first, I silver soldered the 4 joins on the super heater, and all went well.

The firehole is oval shaped, and the plans call for a rectangular door.  So I spent some time planning the machining for the rectangular door boxed section.  Then I thought … hang on…. this oval is really nice… why am I hiding it behind a rectangle ?

So back to the computer, and I worked out a method to make an oval door.  A bit like a hobbit door, with an adjustable vent.

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And here I am, machining it with a 2mm cutter.  In 1mm deep bites.  That brass is 4mm thick.

And I made a bracket to complete the hinge….

Drilled the holes for the 1.5mm pin…..

And the f*****g drill bit broke!!!!

I could not get it out.  It was a cobalt bit, and all of my methods for digging out broken bits were tried, taking a couple of hours, and failed.

So I reshaped the hinge end of the door..

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and I will silver solder a hinge end on tomorrow.

6″ Vertical Boiler.Spearhead Superheater

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.

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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.

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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.

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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.

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