johnsmachines

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. I read every comment and respond to most. n.b. There is a list of my first 800 posts in my post of 17 June 2021, titled "800 Posts"

Tag: boiler

June 15, 2018

6″ Vertical Boiler- the Firehole

The firehole is the opening where coal is shovelled into the firebox.  It is oval shaped, and is exposed to the boiler pressure.  It is made from thick copper tube.  Oval holes must be formed through the boiler wrapper and the firebox wrapper.

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The elliptical hole in the boiler wrapper, and the firehole tube.

The first task is to shape copper tube which is circular, into oval shaped tube.  I decided to make an oval shaped split wooden form and to compress the annealed copper tube with the form.

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The wooden slab is cut into 2 pieces which are then cramped together, and the oval hole is CNC machined.  

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A 1″ 25mm length of 3.2mm thick walled tube is cut off, then annealed.  Note that I have upgraded my forge.  I bought some aerated concrete blocks (Hebel), and enlarged and encased the forge.  The white Hebel blocks reflect the heat and the forge temperature rises quickly.   the outside of the forge remains quite cool, testimony to Hebel’s insulating properties.  Hebel is quite inexpensive.  A 600 x 200 x 100mm blocks costs $AUD4.60.  Heating time is 60 seconds, vs 90 seconds with the previous setup.

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The wooden form and the unshaped thick walled copper tube.

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After squeezing the annealed coper pipe in the form, using a 6″ vice.  Nice elliptical shape.  Note the pencil witness mark.

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Then the elliptical hole is cut into the boiler wrapper.  The vice jaws were replaced by temporary aluminium jaws 4″ high, adequate to hold the 6″ diameter tube.  Cutting the elliptical hole on the CNC mill.  There are wooden plugs in the boiler tube to prevent the boiler tube from distorting

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The finished boiler hole and the elliptical insert.  This was tense machining. 

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The fit is a bit too tight.  I will take off another 0.1mm so it is an easy sliding fit, suitable for silver soldering.    Then to cut the same elliptical hole in the firebox wrapper, but while the main cylinder is set up in this position I can cut openings for the ashpan and safety valve bush.                                                                                                                              

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April 17, 2018

BOILER FOR MODEL STEAM ENGINES

Now that the model triple expansion engine is working on steam, I feel able to put it aside, again, and move onto the next project.  The triple is not quite finished.  It needs cylinder lagging, control rods for the cylinder drain cocks, drain tubes for the cylinder drains, and an extra pump for the condenser cooling, and some paint, possibly.

It also needs a boiler.  I would like to exhibit the triple at club demonstrations and public exhibitions, but for that I need a boiler which is certified by our boiler safety authority.  So I intend to make a boiler to AMBSC code, and big enough for the triple or any other engines which I might make in the foreseeable future.

This is what I have in mind….

boiler assembly

This is a copper boiler with a 152mm (6″) diameter barrel, a superheater, gas or coal fueled, and firetubes (most not shown).  The plans call for a 5″ barrel, but I have been unable to find any suitable copper tube, and I have some 6″, so that is what will be used.  I am currently drawing up the plans.

The certification process here in Australia requires the following steps:

  1. Preliminary discussion with the boiler inspector (done)
  2. Submission of 2 sets of plans to the boiler inspector.  If acceptable, one set is signed off and stamped and returned.  The other set is held by the inspector.
  3. Inspection of the prepared components by the inspector prior to soldering/brazing/welding.
  4. Inspection of the firebox and tube assembly after soldering/brazing/welding.
  5. Inspection of the barrel and outer wrapper after soldering/brazing/welding.
  6. Testing the boiler after completion.  This involves a hydrostatic test, at double working pressure for 20 minutes, then a steam test at 10% above working pressure.

If it passes, the boiler is certified for 12 months, after which it must be retested.  If it passes the retest it is certified for 3 years.

The certification process is performed by volunteer inspectors attached to model engineering clubs, and is done at no cost.

However the materials for a boiler like this are quite costly.  I managed to obtain some  copper tube for the wrapper, and bought some copper plate for the firebox and boiler ends on Ebay.  Bronze for the bushes from a local bearing supplier (LG2), and firetube copper tube from local plumbing supplies.  All up, so far, is approaching $AUD1000.  And yet to be factored is the safety valve, various cocks, sight gauge, hand pump silver solder.  And I intend to make and fit a steam driven feeder pump, and possibly a steam injector.

If there is any interest in this project I will post progress notes and photos.  Let me know.

10 Comments
July 7, 2015

MODEL ENGINEERING EXHIBITION at BENDIGO, VICTORIA, AUSTRALIA

Bendigo is a beautiful city in the middle of Victoria, with a rich history, literally!

The city is in the “golden triangle” of Victoria, named for the huge quantities of gold which were mined from the area in the second half of the nineteenth century.

With that mining-engineering background, it is not too surprising that Bendigo has an enthusiastic and active metalworking, engineering, modelling club, and every two years they host an exhibition, which I attended for the first time last weekend.  And what a terrific event it was.   Well worth the 3 hours each way drive.

Following are some photos of a few of the hundreds of exhibits.  Please forgive me if I don’t remember some of the names and details.  The standard of the work varied from excellent to absolutely bloody unbelievable.

Welcoming visitors at the entrance, was Gerard Dean, with his 1/5 scale Tiger tank, powered by a V12 150cc engine.  Belching smoke, and overcoming any obstacles and visitors in its way.  There are a few of these models around the world, but very very few have a 12 cylinder gasoline engine which looks and sounds the part.  Gerard has taken his model to many countries, including the USA.  He does occasionally strike a hitch at customs, and usually has to prove that it will not fire real ammunition. The country which gave him the hardest time getting it over the border??  You guessed it…   Germany.

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The Germans were a bit upset that the engine valve covers are stamped “Made in Australia”.

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Inside, there were 2 large rooms, with models, tools, books, kindred spirits who were delighted to have a chat.

Inside, there were 2 large rooms, with models, tools, books, kindred spirits who were delighted to have a chat.  I recognise the beam engine and quorn T&C grinder in the foreground.

Eccentric Engineering had a display of his Diamond Tool holder, but I have already bought 6-7 of these in different sizes. I did top up my stock of Crobalt cutters.

Eccentric Engineering had a display of his Diamond Tool holder, but I have already bought 6-7 of these in different sizes. I did top up my stock of Crobalt cutters.

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Eccentric Engineering was showing his Acute Tool Sharpening System. I was very tempted to buy his kit of parts, but was fearful of my reception from SWMBO, if I returned with yet another tool and cutter grinder.

A very impressive Atkinson engine. it was running earlier. Les are you there?

A very impressive Atkinson engine. it was running earlier. Les are you there?

The Eccentric T&C cutter grinder kit.

Of the many outstanding models, this one was superb. Not totally finished. But totally appropriate for Bendigo. Of the many superb models on display, this one was outstanding. And totally appropriate for Bendigo, given its mining heritage.

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Pictured with the maker. The twin double acting steam engines were running on compressed air for the exhibition. Will look great running on steam!

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Some future model engineers, viewing a very nice, running, triple expansion steam engine.

Some future model engineers, viewing a very nice, running, triple expansion steam engine.

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A beautifully finished Bolton 12 beam engine

A beautifully finished Bolton 12 beam engine.  Makes mine look a bit drab.

10 cylinder radial aero engine, made from stainless steel.

10 cylinder radial aero engine, made from stainless steel by Bob Bryant.  Hmm, maybe a 9 cylinder.

 

I particularly likes this working Meccano model of an excavator. The digging action was particularly realistic.

I particularly likes this working Meccano model of an excavator. The digging action was particularly realistic.

Another beam engine, this one made using Meccano. Takes me back 55 years!

Another beam engine, this one made using Meccano. Takes me back 55 years!

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A particularly beautifully finished oscillating engine, totally made from bar stock.

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4 Comments
May 25, 2015

BOILER PAINT

I am waiting for some new 2mm milling cutters to arrive before I tackle the steam passages in the triple, so I decided to apply some finishing touches to the Bolton 7 boiler.

The aluminium castings on the ends were removed, and painted with a high temperature engine paint.  While the boiler was in pieces I connected the steam exhaust pipe from the engine to the boiler chimney.

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The before shot. The engine and its boiler are sitting on a mantelpiece in our living room.

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It looks better with the ends painted matt black, yes? I suppose that I should have also painted the brass sides and copper boiler, but I really like those metal colours. 

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Video | May 7, 2014

MORE LAKE GOLDSMITH MACHINES

There are 2 “rallies” at Lake Goldsmith each year.
This collection of pics and videos is from some of the 65 sheds containing exhibits.
I thought that I would remember the details but there were so many……
Also, just iPhone pics. Next time I will take my Nikon.

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Video | May 6, 2014

INCREDIBLE LAKE GOLDSMITH PARADE OF STEAM ENGINES

This grand parade deserved more than my iPhone video. The battery failed after only about 1/4 of the parade. It was amazing and inspirational, and uplifting.
Absolutely must see.
Next grand parade in Nov 2014. 1st and 2nd. I WILL BE THERE.

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Image | April 19, 2014

Boiler for steam engine

Just a bit more finishing on this boiler.
At the chimney end there is now a removable cover to provide access to the smoke box (the round aluminium cover with the brass lever nut), and a sliding door to provide access to the firebox.
You can just see the Bolton 7 engine behind the boiler. They are both sitting on a marble shelf above the fireplace in our living room. I was amazed when SWMBO said that it could live there.
My 18 month old grandson loves to be lifted up to the “teamengine” so he can turn the flywheel.

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Video | April 12, 2014

Making a copper boiler

The boiler which powers the Bolton 7 steam engine is 250x100mm. The case is 1.6mm thick and the ends are 3mm thick. It has 7 x 6mm copper stays. The safety valve, pressure gauge, sight glass and valves were bought items. It operates at 60 psi but has been tested to 120 psi. Propane gas fuel.

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Image | February 26, 2014
Boiler and engine incomplete

Gas fired 4″ boiler Bolton No 7, double action, single cylinder stationary steam engine. I will download  a video of the engine operating on steam, soon.  Keep watching.

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