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.

Back to the Trevithick Dredger Engine Model – the lagging.

The only surviving Trevithick dredger engine, in the London Science Museum, shows no signs of ever having been lagged.  I know this, because I examined it closely, recently, during my UK trip.

No lagging, no marks in the paintwork, which would indicate wooden lagging strips ever having been attached.

But, we know that Trevithick readily adopted ANY improvements to his designs, and lagging was appearing on engines at about the epoch of the dredger engine design. Plus, his engines were in use as late as mid 19th century, and lagging was well established as a normal feature by that time.

And, my model definitely needs some efficiency improvement.  Using a 40kW burner to power an engine of this size is ridiculous.   So I Have added some lagging.

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Equipment for applying lagging, from the left…   scroll saw, super glue (I used 6 tubes), strips of wood (in this case, Australian Jarrah, grinder for shaping, Dremel for shaping, good light, and the engine with some of the strips glued in place.

I used about 48 strips of wood with some spares.  These were cut and sanded in advance.  5mm x12mm x 130mm.

The Super glue is used to hold the wood strips in place temporarily, until the brass boiler bands are installed.

I started at the top, and worked my way down on both sides.  Most effort is made in fitting around  pipes and boiler bosses.  Unsatisfactory strips are levered off and scrapped.

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A rebate was milled on every wood strip, to permit removal or tightening of the boiler end plate nuts.

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I used rubber tree ties to maintain pressure until the glue dried, but in most cases I just applied finger pressure until the wood stuck fast.

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Some pipes and fittings necessitated grooves being made with round files.

Super glue does not provide a permanent bond to copper for some reason.  And it certainly will not survive the heat from steaming.  But it is fine for a quick and temporary bond.

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After making and applying the brass boiler bands (this was covered in the “6”vertical boiler” posts) I used olive oil to seal the wood.  See discussion which follows.

I chose olive oil to seal the grain openings of the jarrah.  I know from previous firings that the temperature of the boiler shell does not exceed 100ºc.  Olive oil will not smoke or flame until the temperature exceeds  200ºc, which is higher than any other common oil.  Also, as a failed olive farmer, I have plenty of old olive oil.   At worst, my engine steamings might smell like a fish and chip shop.  And refreshing the oily surface will be quick, cheap and easy.  And the olive oil will not form a skin which might peel or flake.  Anyway, this is “model and experimental” engineering.  If it does not work, I will make some new lagging, alright!.

And I took some more photos with my Panasonic Lumix 100-2 camera…….

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Still some more painting required to the end plate, and some fittings.

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That domed boiler end with the cylinder protrusion also needs some paint.  But the lagging looks good hey?

Even SWMBO has relented…  “It can go with the other engines”.  It will, when it is finished.  Still requires more painting.

Model Engineers have Other Interesting Hobbies.

When I visited York, UK recently, I met up with a reader of the blog, Jennifer Edwards.  Jenny had set aside 2 days, and we visited the Kelham Island industrial museum in Sheffield, and the York Railway Museum, both of which have featured in recent posts, and both of which were wonderful.  It was made much more enjoyable by having a kindred spirit as company.  And fortunately both of these sites were new to Jenny also, and equally enjoyed by her I believe.

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Jennifer at the 12000hp steam engine, Kelham Island.

This post is about one of Jenny’s many interests.   Metal detecting.

I am not sure what attracted Jenny to this activity, but she joined a local detecting club, and spent many days checking English fields with the club, searching for interesting metal objects.   With fairly limited success.

Then one day she had the idea of checking a local rugby pitch.  Surprisingly, the rugby club agreed, with some stipulations I am sure, about replacing turf, minimal disturbance etc.

Within a short time, Jenny was getting positive signals, then carefully cutting out a square of turf, then digging out the ground, in most cases no deeper than about 150-200mm (6-8″).  And finding coins, rings,  (gold, platinum, some diamond), musket balls and other interesting objects.  Obviously, the field had never been previously scanned.  And research later revealed that the area had been the site of a village fairground.   And before that a walled area for defence against sea raiders.  Very old apparently, because some of the coins were Roman.  Others were of later vintage, medieval, Victorian etc.  About 200-300 objects of interest were found by Jenny.

The find was unusual, and was written up in a metal detecting magazine. (The Searcher, September 2018).

Jenny showed me some of the oldest coins, and I was flabbergasted when she said that I should keep one, as a memento.  I did say that I couldn’t possibly… but I confess that holding something so old, much less being given it, was overwhelming.  I accepted.

Here are some photos of the coin.  It is a silver denarius, minted in Rome in 137BCE.  i.e. it is 2156 years old.  Minted in the Republican era, before Julius Caesar, before Christ.

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The image is of Apollo.  “Tampil” is the family name of the minter.

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The reverse shows Apollo on a 4 horse chariot, holding a laurel branch in one hand and a bow and arrow in the other.  The words “Roma”  and “Baebilius” (part of the minter’s name) are clear.

The coin is small (about the size of an AUD 5 cent piece), silver, and the images are amazingly clear.  The Tampilius family was well known, having provided senior officers for the Roman infantry, and at least one consul of Rome.    The right to mint coins was granted to some high status private individuals in ancient Rome.  The value of the coin was roughly equivalent to its value in the silver it contained.

It says heaps about Jenny’s  generosity that she gave the gold and platinum rings to the rugby club.

 

 

 

 

Modelling Jeeps and Tiger Tanks (books)

I received 2 more books from Pen & Sword  for review, and these are both directed squarely at modellers.  They both contain interesting information about their use in WW2, but are mainly about the external appearances, and configurations.  Not much information about manufacture, strategic importance, or mechanical aspects.

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THE JEEP

Second World War

by Lance Cole

 

This large format, 64 page book is written for Jeep enthusiasts, Jeep modellers, and Jeep restorers.

This reviewer is an experienced 4×4 driver and owner, and interested in WW2 vintage Jeeps from an historical perspective, and for technical comparisons.

The book will have enormous appeal to its target audience, but less so to the casually interested reader like me.  It does include some general historical notes and comments, but these seem incidental to the main subject matter, which is about modelling of the body work and weapons.

There are many photographs of Jeeps in wartime configurations, and mounting various weapons.  Also lots of photographs of model Jeeps.

Modelers and restorers will love it.

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TIGER 1 AND TIGER 11 TANKS

German Army and Waffen-SS

The Last Battles in the West 1945

by Dennis Oliver

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This is another of the series of Tank Craft books which aims to provide model-makers and enthusiasts with photographs and line drawings of battle tanks which are popular subjects for modelling.

The 64 page , large format book has many such images, as well as notes about the military actions, as far as is known, of the German Tiger tanks in 1945.

The illustrations are of the tank exteriors only.  They are detailed, colour and of high quality.

A 15 page section lists and assesses commercially available kits from various countries.

Tiger Tank modellers and illustrators will love it.

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Large Scale Warship Models (a book review)

LARGE SCALE WARSHIP MODELS

From Kits to Scratch Building  by Kerry Jang

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This 110 page, hard cover book is aimed squarely at the model ship builder.  The title is slightly misleading because the book is more about methods of modelling, rather than models, per se.

The author, an expert and award winning modeller, describes the methods he uses to make superb, large scale ship models.  The methods include up to date techniques including 3d part printing, rubber mold making,  and use of modern adhesives, paints, materials etc.  There is a very interesting section on the why’s and wherefores of large scale ship modelling, including intriguing references to Zen and Nirvana.

The book is lavishly illustrated with many photographs of works in progress and techniques.  The text is clear and concise.

Although I am entranced by ship models in museums, my own interest in modelling is with stationary steam engines.  I found much of the advice and techniques in the book to be of interest and relevant to my own modelling efforts, particularly the sections on assembly, painting and finishing.

A handsome, useful book, which I am pleased to add to my library.

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“parts that don’t fit”. Now that will be useful.

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A handy painting technique which had never occurred to me.

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A lavish, quality production. £25.

 

London Museum of Science Revisited

I am back in oz as of a few hours ago.  Freezing and wet.  Was 26c in London today.

On my last afternoon in London I had a few hours spare.  So I caught the tube to have a final farewell to the Trevithick dredger engine and to reshoot some photos which I had messed up at my visit 3 weeks earlier.

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Trevithick dredger engine in the LSM.

…and I spent a very pleasant hour photographing the engines in the Energy Hall again.

And on wandering further into the building I discovered that on the previous visit I had totally missed about 2/3 of the entire museum, including the model of the Trevithick road vehicle which had been made as a concept model by Trevithick’s brother in law, a clock maker.

Unfortunately it was bottom lit and behind glass, so very difficult to get good photos.

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From above

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From the side.

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The model is more akin to his road vehicle “Puffing Devil” than the rail locomotive.

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Quite modern looking lathe by Richard Roberts 1807.  With lead screw and outboard gears for threading.

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Beam engine designed by James Watt 1797.

 

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Model of a steam powered workshop, with many tiny exquisitely modelled lathes, shapers, presses, saws, and a steam engine.  Those lathes are about 3″ long.

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And a 1:12 model of a pressure gauge of James Watt, 1794.  60 years before the invention of the Bourdon tube.

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And this one amused me.  It is a 1987 Colchester CNC lathe, with Fanuc controller.  It is 2 years newer than my Boxford CNC lathe.

This really was the finale of my adventures in the UK.

 

Final Day in UK. 2 more museums.

First, I was avoiding posting photos because I was at 99.9% of my allowed storage at WordPress.  So I have deleted a lot of old videos, and now have some headspace.  If you search my old posts you will find some blanks.  If they are crucial, message me and I will get them to you some other way.

Today was my final day of sightseeing.  Beautiful sunny weather in Portsmouth.  I am mentally gearing up for home and family, who I have missed.  But frankly, this tour of museums and engines and mines and ships could not have been done with wife/family in tow.  I consider myself incredibly fortunate to have been able to do just what I felt like, for the past 3 weeks.  And I have enjoyed making these posts in the evenings.

So today, I visited 2 more museums in Portsmouth, on the Gosport side of the harbour.  Smaller, specialist  museums.  Not for everyone, but I thought that both were terrific.  They were 1. The Explosion Museum and 2. The Royal Navy Museum of Submarines.

The explosion museum was quite close to my BNB.  A walk along the waterfront, past many, many leisure yachts, and the odd hulk.

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Fighting off the crowds on the waterfront, Gosport, Portsmouth

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The “Explosions Museum” is located in an old set of buildings, built as you can see, in1771.  The walls are 8′ thick.  

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And as I entered, I noticed this lump of steel, weighing 1.5 tonnes.  That is my tape measure.  I don’t trust OP’s measurements.  It is armour plating from the German battleship “Tirpitz”, sunk by British airplanes in a Norwegian fiord in WW2.   I measured it at 450mm 18″ but the notice says 15″.  Whatever.  

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Cutaway of a WW2 magnetic mine.

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The breech of a 15″ naval gun.  Massive.

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One of the buildings.  Those walls are 8′ thick!

There were many more exhibits, mainly of WW1 and WW2 vintage.  But a few more frightening, modern ones too.

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Where the gunpowder was stored.  Now used as a wedding reception venue!  Hence the balloons.

I noticed this as I walked back.

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Rotting away to nothingness.

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I have to protect my knees these days, so I drove the  2 miles to the Royal Navy Submarine Museum.

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This is a cold war, diesel powered sub.  I was surprised how big it was.  1600 tons.

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The bow (pointy end)

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And it is probably pretty obvious, but it is still just another boat.  With lots of pumps, valves, 2 engines, nav gear, torpedoes, and crew facilities.

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and dedicated volunteers, in this case an ex-submariner.

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Forward torpedo room.  The 1.5 tonne torpedoes were basically manhandled into the launching tubes shown, using a gantry (not seen).

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Torpedo stored against the wall, and the gantry above.

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There is not much room.  Crew bunks.

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Plenty of interest in the loo

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One of the twin diesels

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and the machine shop.  No brand.  About the size of a Myford.

 

The guide’s final comment was that this 1980-90’s technology is obsolete.  It is all about nuclear submarines these days.

Then into the actual museum, where there was a mini sub, and the first submarine in the Royal Navy.  And a lot of simulation games to amuse the kids.

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The mini sub.  British.  Used in WW2.  A six man crew from memory.

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1900.  9 man crew.  Canaries were actually rats.  Enlarge to read the details.

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Riveted hull.  Circa 1900. 

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Petrol engine when on surface.

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Single forward torpedo tube.

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Looking aft past the petrol engine

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The outer skin was about 3mm thick.

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No welding.  Entirely riveted.

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In the car park was an unlabelled, 7 blade bronze (?) prop.  ? off a nuclear sub.

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Submariner officers were in “the trade”.  I bet that you did not know that one.

 

So, tomorrow a drive to London to drop off the rental car, and fly out the day after.  I am planning another quick visit to Fort Nelson, where I am hoping to use a tape measure on one or two aspects of the Ottoman Bombard.  Maybe a model bronze version of the bombard in my future, hey?

So, I hope that you have found some of these posts of interest.  My usual workshop posts will reappear soon.  And maybe an occasional one about UFO’s and Antarctica.  See ya.

Portsmouth UK. 2 more great museums.

Not strictly museums.  Ships actually, but displayed as museum pieces.  Both incredibly interesting.  And I am not including Nelson’s “Victory”.  I had seen it 40 years ago, and after 5 hours of walking, my knees told me that enough was enough.

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“Victory” as seen today.  Still the biggest crowd pleaser.  Now sitting on props in a dry-dock.

My main targets today were “Warrior” and the “Mary Rose”.

Warrior was built in 1860.  The age of steam was well underway.  But to date, warships were still sailing ships.  However the French were rebuilding their navy after their humiliating defeat at Trafalgar, and they had built the first propeller driven, steam powered, iron clad (wooden ship with steel plate cladding).  The Brits were not going to stand for that, so they built “Warrior”.  The most powerful, fastest battleship afloat, and more than a match for anything else in the world.  By the time it was built, the French and the Brits were allies, for a while.  Warrior was destined to never fire a shot in anger.

Today it sits moored at Portsmouth’s Historic Dockyard, and is a fascinating mixture of steam and sail, muzzle loaders and breech loading guns, Steel and wood.  It is a big ship, 127.5m (418′) long, and 9210 tons.  It looks a little odd to our eyes because it has no superstructure, except 2 funnels, and the foremast and mainmast are widely separated.

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Steel framed, 18″ of oak lined, plus 4.5″ of steel plate.   The masts are steel, with wooden upper sections.  The figure head is a Greco-Roman warrior.   706 crew.

This ship could make 14.4 knots (27.7kph) under steam, 13 knots (24kph) under sail, and 17.2 knots (31.9 kph) with sail plus steam.  Not as fast as a clipper, but much faster than any other warship.

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4.5″ (114mm) armour plating, plus 18″ (460mm) teak planking.

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Traditional spoked steering wheels were duplicated on 3 decks.

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Hundreds of Lee-Enfield percussion cap rifles were available.

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And cutlasses, to repel boarders.  Muzzle loading cannon tools to left.

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And Colt 45’s for the officers.

But the main armament was of course the big guns.

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The gun deck was similar to that of the 120 year older Victory.   except that these are huge 68 pounders.  19 man gun crew for each.  A mixture of 10 x 110lb breech and 26 x 68lb muzzle loaders.

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And the crew still slept in hammocks on the gun deck.  And ate there.

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But they had washing machines  and lavatories (first ever warship with these)

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and baths!

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The steam engine, surprisingly was a relatively primitive, but powerful twin cylinder, single expansion, horizontal trunk engine of 5469hp, driving a single propeller.  The 10 boilers were box shaped, double firebox, no fire tubes.   22 psi only.

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Coal was delivered in small coal trucks on rails, and shovelled into the firebox’s.  No gauges,  except in engine room.   853 ton coal stowage.

I have many more photos of Warrior, but I am down to my last few megs of storage, and I want to show some pics of the Mary Rose, which is probably the most stunning museum display I have ever seen.  I know that I keep saying that, but this really is…..

Mary Rose was a 35 year old warship which sank in 1545 during the battle of the Solent, against a huge French invasion fleet, while Henry 8 was watching.  No-one really knows why it sank, but the most popular theory is that bigger cannons had been installed, requiring low gun-ports to be cut into the the hull, and that after firing a broadside the ship had turned and the open gun-ports shipped a lot of water, which sank the ship.   Whatever, the ship was unable to be raised. Most of the hull gradually rotted and broke away.  But the parts which were under silt did not rot, and were still there when discovered over 3 centuries later.  In 1985 the remains were raised, and painstakingly preserved.  A museum to house the remains was specially built.  And it is stunning!  No other word for it.  Here are a few pics from today.

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Mary Rose.  Pride of the English fleet.

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and you know who.

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About 1/3 of the hull remains, including most of the keel.

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The bronze cannons are in fairly good shape.  Only real remains are displayed.

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This is a breech loading iron cannon, made of strips and hoops of iron.  The ancient wood and iron has been treated for years with PEG (polyethylene glycol) before going on display.

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Hundreds of ewe long bows were found, many still in their storage boxes.

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And many skeletons.  This one was a bowman.  That humerus (upper arm bone) is massive.  There were 35 survivors out of the many hundreds of men on board. 

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And a reconstruction of the bowman.

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And sadly, a dog.

A most remarkable museum.  Add it to your bucket list.  Allow at least 2 hours.

 

 

 

 

 

Fort Nelson. The Ottoman Bombard revisited.

Just to refresh your memory, if you are a long term reader of johnsmachines.com, this is the model of the Ottoman Bombard which I made several years ago …

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…but it is not finished.  I could not find a picture or drawing of the touch hole anywhere.  Requests to the museum drew no response.

Plus, I had some questions about how the square holes were made.  These were designed for levers to be inserted so the cannon segments could be screwed together.  But were the round pegs cast with the barrel and breech, or were they somehow added later?

Also, I wanted to take a close look at the huge V threads to see if I could work out how they made them.

And frankly, I just wanted to touch it.

It is currently on display at The Fort Nelson Royal Armories Museum near Portsmouth UK.  And I visited it today.  I allowed an hour to inspect the bombard and have a quick look around the rest.  4 hours later I staggered out.  This museum is another fantastic place to visit.  I will do a more complete report in another post. For the moment I will deal with the bombard.

Firstly the touch hole.  Save these photos.  They do not appear anywhere else!

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Not much design finesse there!  The wide opening becomes narrower about 25mm in (just visible).

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Next, the bombard as it was today..and I touched it!

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It is 17′ (5.2m) long, weighs 16.8 tons (17000kg).  It was made in 1465 by Munir Ali, as a copy of the bombards made by Orban, a Christian (Hungarian? German?) for Mehmet 2, the conqueror, who took Constantinople in 1453 on 29 May, (today in Oz).  Orban’s biggest bombard, named Basilica reportedly was 27′ (8.2m) long!

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That’s my hand underneath the “pins”.  Actually levering braces, cast integrally with the breech and barrel.  You can see dents, probably made by the levers.  In doing this I realised that the “pins” are not cylindrical, they are half a cylinder (split lengthwise).  The half cylinders allowed clay or something similar to be placed around the mold, under the half cylinders, and for the gaps between the half cylinders to be filled with clay pieces, to be broken out after the cannon casting.

And the huge threads…

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Well, I am no closer to understanding how these were made.  They are rough and irregular.  I would guess that they were carved in wood, then a clay mold made from the wooden model and baked, then the clay shape used in the final casting, and broken out afterwards.  Any other ideas?

I really enjoyed this visit.  If I have any WordPress storage remaining I will post some photos of some of theother artillery pieces later.

When I finally run out of space, I am afraid that will be the end of my posts.  Thankyou all for following.  It has been great fun posting, and answering comments.

Just in case this is the last post, I have to post these pics of the WW1 British rail gun.  It is truly awesome.

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Cannon caliber 18″.  The Yamato (Japanese WW2 battleship) had 9 guns of this caliber.

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The breech OD  is at least 5′- 6′

 

BT. Before Trevithick.

Before Trevithick were Savery, Newcomen and Watt.  And way before them, Hero of Alexandria (1st century AD)

Thomas Savery, a military engineer from Devon, took out a patent in 1698 for a steam operated pump.  It had no moving parts, except some valves.

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It had 2 low pressure boilers.  Steam from one boiler was introduced into one chamber, and water was then introduced which condensed the steam, forming a partial vacuum, which sucked up water from below.  Steam from the other boiler was then introduced, which pushed the water upwards.  As a pump it was a failure, and it is not known if any were made.  Modern reconstructions have also been unable to pump water successfully. But the patent lasted, and forced Newcomen to involve Savery with his invention in 1712.

Thomas Newcomen was an ironmonger and Baptist lay-preacher from Dartmouth, Devon, and he is the reason that I am currently in this pretty Devon town.  There is an original Newcomen “atmospheric engine” in Dartmouth.

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(taken at an angle to avoid window reflections)

The Newcomen pump, (for pumping water from the mines was its purpose) also used the condensation of steam creating a partial vacuum, as its principle of action, and it was quite successful.   So successful in fact, that more than 600 of them were built, and they continued to be built well after the improvements of Watt and Trevithick, into the nineteenth century.  In the diagram above, the 22″ power cylinder is on the right, and the pump cylinder is on the left.  The genius of this design is that the pump can operate in the depths of the mine (or canal or military trench) while the engine remains above ground.

It is incredibly inefficient in thermal terms, converting only 1:200 of the energy from burning coal into the mechanical energy of the pump, but it was by far, more powerful than any pumps driven by man, horse, wind or water at that time.

The room in which the Dartmouth engine is housed is just bigger than the 15′ high engine, so pictures are difficult.

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All wood, except the power cylinder on the right, and the pump and pipes (not seen).  The curved ends of the big wooden beam keep the piston rod and pump rod vertical.  Cylinder boring had not been introduced yet, so the gap between piston and cylinder was up to 1/4″.

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The valves to admit the steam and water were originally operated by hand, but later some automated simple levers were introduced.  Note the square nuts (original).  It appears that the woodwork is mostly original, albeit repaired in places.

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The pump connection

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This power piston has a bore of 22″ (560mm), but they were built increasingly bigger, up to 80″ (2032mm).

The Newcomen engines were simple, and effective.  Their main problem was that they consumed vast quantities of coal.  They were widely used, but there was/are no coal deposits in Cornwall, and transporting coal from Wales was costly, and taxed.

James Watt‘s big contribution to steam engines was to add a condenser to the engine, which was separated from the power cylinder.  That doubled the efficiency.  He also sealed the top of the cylinder, so both strokes of the piston rather than just the down stroke, were power strokes.  But it was still a vacuum powered engine, and therefore had an absolute limit of working pressure of something less than atmospheric pressure (15psi).

Richard Trevithick‘s main contribution in 1800 was to increase the steam pressure available, by inventing the “Cornish boiler” which produced steam at 50psi, and even up to 145psi.  This more than doubled again the thermal efficiency of the steam engine, and made it much more compact, leading to his applications of steam engines in road vehicles, railway locomotives, ship engines, and industrial stationary engines (like my model dredger engine).

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Watt modified Newcomen engine on the left, Trevithick dredger engine on the right. Size comparison.

Tomorrow I am driving to Portsmouth.  So I will leave the west country inventors of steam engines.  It has been a fascinating journey.

First stop, Fort Nelson.  To renew my acquaintance with the Ottoman bombard, which was the subject of my blogs several years ago.

 

Tin Mines

One of the essential discoveries by our ancestors, in taking us from being hunter gatherers to “civilised” sapiens, was how to make metal implements, weapons, instruments and engines.  Copper was the earliest.  Probably found by lighting a  camp fire over a rock containing copper, and seeing it run.  It could be moulded into useful implements, but it was soft, and maleable.

Copper and tin often are found close to each other, so it is possible that the ancient camp fire melted both tin and copper to form bronze, which is much harder, and still used in the space epoch, as a hard, good conducting, mouldable metal.  Or more likely, that some copper which was melted and cast into something useful, was contaminated with tin, and the accidentally resulting bronze was found to be much harder and more durable than copper.

The problem is that tin is a relatively rare metal in earth’s crust, and its most common occurrence is in the form of crystals of cassiterite, which are inclusions in granite.  There is evidence that tin has been used since ~2000BCE.  Ancient man probably mined surface deposits of cassiterite in various locations, most particularly what is now Cornwall, UK.  Tin was traded from Cornwall long before the Romans arrived, and by then, was obtained by deeper mining.  Mining continued even though iron was available.  Bronze lasts  much longer than iron.  Indeed, many more bronze implements and weapons have been discovered from antiquity, because the iron ones have rusted away to nothing, and the bronze items often are in close to perfect condition.

Tin and copper mining continued in Cornwall until very recently.  I am not aware of any commercial mines currently operating.   But the evidence of mining in the 18th, 19th and 20th centuries is everywhere to be seen in the form of smoke stacks, and engine houses, which once housed mighty steam engines.  In the past 2 days I have visited 3 mines, which have differing approaches to tourists.  They were The “King Edward Mine Museum”, “Geevor”, and “The Levant”.  I did photograph Ding Dong from a distance, because that was the mine of which Richard Trevithick was the captain.

King Edward Mine Museum.  Although the site of a mine, this is a museum of mine engines, boilers, and machines to separate the tin ore from the parent granite.

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From a steam beam engine which provided power for the winding winch, the beam and connecting rod.

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19th century photo of miners on a “man engine”.  To decrease the time it took for miners to climb up and down ladders, sometimes up to 2000 feet(!) to get to and from the working face, this was devised.  There is a series of wooden beams, fastened together end to end, totalling the length of the depth of the mine, and every 12 feet there is a small step.  A steam engine at ground level raised and lowered the wooden beams and steps every few seconds by 12′.   The miner had to step onto the moving step, be raised 12′ then step off onto the platform above.  Perfect coordination and timing was required.  Even using the engine, it would take 30 minutes to go up or down 2000 feet.  Needless to say it was dangerous, and many injuries, amputations, and some deaths occurred from miscalculation.  There was a disaster at the Levant Mine where the main beam broke, killing 31 men who were on the man engine.  OH&S is not total BS.

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The remains of the engine house and chimney at King Edward Mine.  Granite blocks were preferred to hold the weight of the large beam engines.  And the beam weight was taken directly by the walls.

Geevor Mine closed later than King Edward, and the ore processing machines are substantially intact, and date from early 20th centuery.  It is on the coastline of Cornwall.

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Geevor Mine.  The tower with the wheels is the headframe.  The engine house is on the right.

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Like gold sieves, the denser tin ore is sieved from the lighter rocks.  The bottom machines are a last phase of grinding.

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Boilers.  Lancashire type I think.  (my bad.  Not Lancashire.  Egg end

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Ore train, battery powered.  Earlier they tried small steam engines, but the smoke was a problem, so they used horses to pull the empty trucks back to the loading areas.  The loaded trucks went to the bucket lifts down a gradual slope, using gravity.  The horses spent 2 months under ground, and were carefully looked after because of their cost, and the trouble of getting them down and up.  At the end of two months they were blindfolded and legs tied, and were lifted using the ore lifting whim.  They were kept in a dark barn for 2 weeks, then allowed out for 6 weeks, before going undergound again.

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Water wheel powered ore crusher.

The final part of this tour, was a walk undergound, through a 350 year old mine, later used as an access tunnel.  They issued us with a helmet and raincoat, and both were absolutely necessary.  The tunnel was about 5′ to 5’6″‘ tall, so the helmet took a battering. The walls were wet, and the roof constantly dripped and ran.  Sometimes the walls were not vertical, but sloped markedly.  Our guide used to be a tin miner, and he told us that they disliked the irregular access, because after placing a charge of black powder, they had approximately 30 seconds to clear the area.  Falling over, or being too slow was a bad option.  And it was pitch black when the lights were out.  This tour is not for everyone.

Prior to pneumatic drills, water fed tools, the charge holes had to chiselled by hand.  One person holding and rotating the drill (chisel), and one or two miners swinging heavy sledge hammers.  Typically it would take 2-3 hours to chisel the 6-8″ hole to take the charge of powder.  They made their own fuses using goose quills end to end, and filled with black powder.   This was granite containing the tin ore.  Very hard stone.  Very few timber props were required once the mine was well undergound.

 

 

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This is a 3D model of one mine’s shafts, adits, and tunnels.   100 miles altogether.  2000 feet deep, and extending inland, and out under the ocean floor for 2000 feet!   Surprisingly, the part under under the ocean was the driest, and was fresh water, except when they accidentally mined up too far.

The final mine which I toured was the richest.  The Levant mine.  It is of great antiquity.. 3000 to 600 BCE and intermittently mined until 1930.  It never really recovered from the Man Engine disaster of 1919.  It is now a National Trust site, and the tour was one of the best I have experienced anywhere.  Again the tour guide was an ex tin miner.  He looked the part, with missing teeth,  west country brogue, and built like a T34 tank.  He was a superb raconteur, with a wealth of stories and knowledge, and answered every question with assurance.  We visited many parts of the complex, including a trip into a mine, with a huge vertical shaft at the end.  Counted the tourists in and out, and radioed the manager in and out.  The tour ended with a visit to the steam driven whim engine.  It was the only engine saved after the closure.  The rest were scrapped.

 

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Levant mine is perched on top of rugged Cornish cliffs.  The cliffs were mined by ancients.  The adit (water drainage tunnel and mine entry is down near sea level.  We did not venture down there) opens near the bottom left of the pic.

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A small part of the Levant above ground complex.

 

 

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The valves of the beam engine

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The beam.  Not the biggest, but it is working on steam.  1840.  Restored 1985.   24 rpm.  690mm bore, 1200mm stroke.  Direct drive to the winding drum.

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I do not have enough space for videos of the engine operating, But will put them on YouTube later.

I have not touched on the topic of women and children working in the mines.  It happened until well into the 20th century.  Look up “Bal maidens” for information on women in the mining industry.  They were a strong lot.

Another highly recommended place to visit.

First Steam Locomotive.

In 1802 a Richard Trevithick designed engine was made by the Coalbrookdale company.  Not much is known about it, but is recorded that the steam pressure reached 145psi!  Trevithick had previously operated his road steam locomotive up the Camborne Hill, but this was the first one to run on rails.

The next one was made for the steelworks at Merthyr Tidfil, Wales.  It was a Trevithick engine which ran on rails.  The owner made a 500 guinea bet with a rival (an astronomical figure.  Somewhere I read that it would be equivalent to a million dollars these days), and in Feb 1803 the engine towed 5 wagons, loaded with 10 tons of iron ore (or coal, not sure), and 70 odd bods, a distance of 10 miles.  There was dispute about whether the bet had been won due to some technicalities, and no record of it being paid, but it was a moral victory.  The age of steam had really begun.

The biggest problem was not the locomotive, but the rails.  They were not strong enough, and frequently broke.  It took the genius of George Stephenson to solve that problem, by using forged iron in preference to cast iron.  And his son Robert to increase the efficiency of the engine and boiler in the form of “Rocket”.  But that is another story, for 30 years later.

Unfortunately the original of the Merthyr Tidfil loco has not survived, but several replicas have been made, based on original drawings.  I saw one of them at Swansea, Wales, not far from Merthyr Tidfil.  Not a steaming day.  It does run.

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Not great photos.  The lighting conditions in the National Waterfront Museum were difficult.

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The typical big, skinny Trevithick flywheel, and driver’s wagon.

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Square main shaft.  Hex nuts were not around in 1802.  

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And that is a view that you don’t often see.  The pressure gauge is definitely a modern requirement, as I discovered with my dredger engine.

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Notice the fish belly rails.  Originals were cast iron.  “Fish belly” shape to increase the strength, but alas, not strong enough.  Hex nuts again!  And those gears have modern shaped teeth.  Quite a few compromises in this replica.

And I have now arrived in Camborne, Cornwall, Trevithick’s home, and the site of his famous trial of the steam road loco.

I made a pilgrimage to Fore St (“Camborne hill”), then to his statue, to pay homage.

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Richard Trevithick.  Genius.

 

Bolton Steam Museum

I was a bit unsure about visiting this one.  A smaller museum, and I knew from the web site that it was not a steaming day.  But it was only a half hour drive, so off I went.  I arrived at the address, and there was a supermarket, but in a corner of the supermarket block there was a tall, old,  sizeable red brick building with no windows.  And a sign… “Bolton Steam Museum”.

In I wandered, and a gentleman in overalls approached.  This was a volunteer working day.  But Ian (apologies if I got the name wrong), stopped his task and spent over an hour showing me around, explaining the finer points of his babies, starting some of them on electric motors to demonstrate the movements, then invited me to a cuppa with his mates, where there was further discussion, mainly about rope drives and stone engine bases.

No parking or entry fee on a non steaming day, (but a donation was appreciated).

The machines were not the monsters of Kewbridge or Kempton pumping stations.  They were mostly from the industrial age of the midlands 1840-1930, powering textile mills, sawmills, and factories.  Some were quite big.  All were beautifully restored and presented, and for once, the descriptive labels had lots of information about the physical characteristics and histories of the engines.  A nice aspect was the elevated walkway down the centre of the room, allowing a good view above the engines.

Some photos follow.  Not as many as the museum deserves, because I am nudging my  Wordpress limits.

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The twin beam engine of 1840 is the oldest engine in the museum. It started life as a twin, but when higher pressure steam became available it was converted to a compound twin.  Note the non identical con rods.  That happened during the conversion to compound.  Partly seen is an excellent collection of engine lubricators.

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This is a “non dead centre” engine.  It has 2 con rods, one for each piston, but only one crank.  Watch the video below and see if you can figure it out.  It ran 100 looms in a textile mill.

 

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Two of the barring engines.  These were small steam engines which were used to rotate the flywheel of a much bigger engine, to its correct starting position.

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For the first time ever, I saw rope drives in action.  Rope made of cotton was preferred, but these days sisal is usually used.  Each rope could transmit 54hp if made of cotton, 30hp if sisal.  They worked in V shaped grooves, and hung rather loosely between the pulleys, the weight of the rope wedging the rope into the groove.  The splices, joining the rope into an endless loop were made by specialists, on the engine, and unlike marine splices, barely increased the diameter of the rope.  The splices which I saw extended over about 2 meters of the rope. 

This museum is another gem.  I have described only a few of the 24 major items on display.  There are many more, including engine lubricators, gauges, and valves.  It was well worth the stay in Manchester, and more than made up for my disappointment at the  Museum of Science and Industry.  Try to see it on a steaming day.  The dates are published on the website http://www.nmes.org

Also, the 36 page “Souvenir Museum Guide” is the best guide of its type I have encountered and contains detailed descriptions and colour photographs of the major exhibits.  It is a steal for £2.  The History of the Bolton Steam Museum is 64 pages, crammed with photos, and after a quick browse I am looking forward to reading it.  Also IMO, a steal at £3.

Sincere thanks to the volunteers who shared their enthusiasm for steam engines with me today.  I do hope to return one day to see the engines running on steam.

 

 

Museums Have Changed. “Rocket”.

I visited the Manchester Museum of Science and Industry today.

As I entered I had to remove my hearing aids.  The noise was deafening.  It sounded like a rock concert with someone screaming into a microphone, as they do.

At the same time, I could see in front of me, Stephenson’s “Rocket”, and that was exciting.  Better still, there were only 1 or 2 people looking at it, so it was possible to get up close or more distantly, to examine it and take photos.

But there was a large crowd on the other side of the room, where the noise was originating.  I was informed that it was “a history of industry in Manchester” lecture, with sound effects and a live performance directed at kids.   Fair enough I suppose.  That sort of presentation might introduce kids to science and museums.  But I am skeptical.  More likely it is an introduction to entertainment, and not much to do with science or industry.

So, I made the most of it and spent quite a while examining Rocket and taking photographs from every angle.  Photos later.

Then I changed buildings to see the Power Hall exhibition of industrial steam engines.  This was the second major reason for my visit to Manchester.   But the Power Hall was closed!  “Temporary” said the sign.  “For one year” said the attendant.  Bummer.

Had a look in the “Air and Space Hall” and was impressed by the size of the twin rotor helicopter, and some other interesting old string and rag airplanes, but that is not really my thing.

Anyway, back to “Rocket”, which you know was the winner of the 1829 Rainhill trial, to pick a locomotive design which would be used to power a railway line between Manchester and Liverpool.  I had seen a replica of Rocket at York.  But this is the real one.   It is almost 200 years old, and it looks the part.  The timber bumper slab has partially disintegrated, and it is likely that some parts have been upgraded.  But those changes are now part of history.

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The firebox water jacket is missing, causing the incomplete appearance.  Wooden front wheel, with iron rim.  Cylinder is horizontal so this is mark 2 or later.

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Rocket firedoor

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Firebox without copper water jacket, from the top

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The only other steam engine on display, (because the Power Hall was closed), was this very elegant beam engine.

Beam engine unlabelled

The flywheel must be 8′ diameter, which makes it a tall, thin machine.  I do like the fluted columns, and symmetrical entabulature.

Beam engine cylinder end

Now, that would make for an interesting model.

 

 

Pontefract. Where playing around can cost your head.

Catherine Howard, Henry VIII’s 5th wife was beheaded in 1542 because she had an affair with Thomas Culpepper in this castle.

The castle, the second strongest in England, after the Tower of London, and considered impregnable, because it is built on rock at the top of a hill, was actually captured during the civil war by the roundheads.  The roundheads had learned that officers of the castle garrison were trying to buy beds.  So some of the roundheads got access to the castle by pretending to be bed merchants, and the castle was taken.

After that the castle was demolished, encouraged by the locals who were fed up with being the target of many armies.

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Not much of the huge castle remains

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There are 3 cannon ball impact craters in this photo.

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Is that a nuclear power plant?

Pontefract is mainly infamous because Richard 2 was murdered here.  A red hot poker allegedly.

Then, after this cheery history lesson, I drove on through the beautiful country of the Derbyshire Dales.  Winding roads.   Deep rocky gorges.  Open fields with stone fences.  To my destination of The Anson Machinery Museum.  This is a smallish museum, recommended by a Melbourne colleague (thanks Ian, if you are reading this), but containing some absolute machinery gems.  Many photos, but I will show just a few.

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It must be 5-6meters long

 

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Ah.  This looks like my sort of museum!

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WTF?  ” A single cylinder, double acting wall engine of 1800.  Note the parallel motion bars, designed to (successfully) circumvent James Watt’s patent.  The gothic arch surrounds are actually steam pipes.  About 5″ tall, plus a large flywheel (partly seen).

 

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The beam engine stands about 5′ high.  Made by Fowlers of Leeds 1872.

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And my personal guide for an hour or two,  an expert steam head, Geoff Baker.

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And just feast your eyes on this beauty!  It is a compound twin, about 3’6″ – 4′ tall.  The propulsion engine for a 63′ torpedo boat 1880.  Not yet formally displayed.

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This is a compound twin from a paddle steamer,  a rich man’s toy.

There were many more engines, including a huge atmospheric engine, a very large compound twin horizontal mill engine, which was difficult to adequately photograph, many oilers, diesels, a steam driven workshop, a steam driven hammer.  A really interesting smaller museum in a beautiful country location.

 

 

National Rail Museum, York, UK.

I am not really “into” trains.  More a stationary engine enthusiast.  But so many readers and friends advised me to not miss the Rail Museum at York that I went today, with my local guide and blog reader, Jennifer Edwards.  To my surprise, Jennifer had not previously visited the museum either.

The museum is located outside the city walls, (the longest city walls in UK), and next to the railway station.  Parking was easy, but not cheap.  $AUD20, which seems to be the standard parking fee in many UK places.  But entry to the museum was free!

There are 3 big halls and an outside area.  The first hall contained a number (didn’t count, but maybe 8) of complete trains with carriages, including a couple of royal trains, with monogrammed carriages, double beds, elegant dining tables with fine china and silverware.  The paintwork gleams.  The metal surfaces are polished.  Altogether a magnificent spectacle.

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Express passenger locomotive nicknamed “Spinner”, 1890-1920.  Average speed 60mph, maximum 90mph.  (we could use some of these in Oz)

For some inexplicable reason I did not photograph the royal trains.

The next building housed the interesting locomotives.

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This is KF7, the largest loco in the collection.  Designed for use in an area of China with steep hills and weak bridges.  The weight was spread over many axles.  Jennifer is 5’6″ 

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This is a replica of Stephenson’s Rocket 1.  It is particularly interesting because many covers have been sectioned or removed, showing the innards.

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This section shows the internal structure of a power cylinder and D valve.

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And the multitube boiler.

I took many photos.  This is showing just a tiny fraction of them.

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And, of course all steam engine buffs will recognise the fastest steam locomotive in the world.  Mallard could reach speeds of 126mph (203kph), towing a full complement of carriages.  Not bad for 1938

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Guided tour of Mallard controls

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Magnificent green livery.  Did not record engine details.

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And this was a full size locomotive, found in a scrap yard and beyond restoration, so it was sectioned to display the workings.  Quite fascinating.

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The “Agenoria” 1829, reminded me strongly of Trevithick’s designs.  The info says that the designer,  John Rastrick, had worked with Trevithick.

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That boiler end, firebox door, water level taps and square nuts could be straight off the Trevithick dredger engine.

We did not see the last areas, because after 4 hours or so, we two seniors had aching joints.   Nice to leave something for the next visit.

Thanks guys, for a wonderful recommendation.

If you have not seen this museum, definitely add it to your bucket list.

And sincere thanks to Jennifer Edwards, fellow model engineer,  for being great company over the last 2 days.

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Jennifer collects clocks, as well as boilers and steam engines.  Here she is admiring a railway station pendulum clock.

 

 

 

The Most Powerful Steam Engine in the WORLD (?).

Excluding nuclear powered steam turbines and some others.  But 12,000hp is not to be sneezed at.

At Sheffield’s  Kelham Island Museum  we (Jennifer Edwards, a blog reader of johnsmachines.com, and I), saw a steam engine which was big, but not as big as the triples at Kempton.  So how can it be “the most powerful etc”.

Well, it is a triple, but not a compound triple.  It is a simple triple.  Double acting.  so each cylinder puts out power like it is the HP cylinder of a triple expansion engine.  It must be a prodigious consumer of fuel and energy.

Why so much power requirement?  Well this engine was used to power a rolling mill, to curve the armour plating of battleships.  Plates up to 16″ (400mm) thick.  The steel was red hot while this was being done, and the plate was rolled back and forth until the desired curve was reached.  Several re-heatings of the plate was required until the desired curve was achieved, so it was important that as many passes as possible were done in the shortest time.  So this engine is capable of full power reversals, very quickly.  Unfortunately there was insufficient room in the museum to fit the rolling mill.

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This large crucible sits at the Museum entrance.  (Jennifer for scale.)

And we saw that happening today.   It was very impressive, and apart from some clanking of the huge spur gears, very quiet.

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Cylinder bores 40″,  stroke 48″, installed 1905, used until 1976.

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50 ton flywheel

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And pinion

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Reversing gear

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Current modern boiler is no match for the original 10 Lancashire boilers.

 

The demonstration lasted only 3 minutes, before the large gas fired boiler ran out of steam at 100psi.  And they had been heating the boiler since yesterday.  Under industrial use, 160psi was used.

Jennifer is trying to obtain some plans to model the engine.  Hmm…I might have discovered my next model too…

Harrison’s Clocks

I have seen these famous clocks in the past,  before I had read “Longitude”.  But now, knowing how incredibly important it was to have an accurate marine chronometer, and knowing the story of how a carpenter, John Harrison, invented, developed, and made the world’s first accurate marine chronometers in the early eighteenth century, I could not miss the opportunity to revisit the Royal Greenwich Observatory, on my visit to Greenwich.

Amazingly, 3 of the 4 clocks are still working accurately.  I am not sure why the final, wonderful, Harrison 4 is not working.  That is the clock which finally made Harrison a wealthy person.

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Harrison 1.  Intriguing mechanism, but had wooden gears and other wooden parts, and was not quite accurate enough.  It weighs 30kg.

 

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Harrison 3.  More compact.  All brass gears and shafts. No bobbing pendulums.   Still heavy, but a bit less bulky.  19 years in development, and still not up to scratch according to Harrison, who was probably a bit OCD.  One aspect which really impressed me with these clocks, was the incredibly high standard of metal work and metal finishing.

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Harrison 4.   Like a big pocket watch.  But won him the prize, and made him a very rich man.  Unfortunately Harrison died not too long after winning the prize.

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John Harrison with his final chronometer.  And a picture behind him of number 2 (I think)

The board which was determining whether his chronometer (number 4) was worthy, dallied and prevaricated to avoid paying Harrison the 20,000 pound prize.  Fortunately, King George 2 intervened and took up Harrison’s cause, and eventually he was paid a total of 23,000 pounds, which made him the equivalent of a modern multi millionaire.

His Harrison 4 kept time on a moving, rocking ship, within 1 minute in 90 days, which was a quantum leap in accuracy, and resulted in vastly more accurate navigation, and saving sailors lives.

“Longitude” is an excellent read.  And seeing these timepieces in reality, was an experience which I will not forget.

Another 1000 ton Machine

I saw Cutty Sark for the first time 40 years ago, and was transfixed by its beautiful lines and fine workmanship of construction .

Like most people I was devastated when it was severely damaged by fire in 2002 (or was 2007?  I can’t remember.  Anyway, they spent a lot of money and time repairing the damage.  And I revisited it today.

What the Cutty Sark Trust has achieved is nothing short of remarkable.

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Today, when I first saw it again, I thought “what is that strange glass structure around the hull?  Are they trying to do something modern and arty?”   The masts, rigging and hull otherwise appeared to be unchanged.

Then when I paid my money and went through the entrance… 1. I felt poorer.   The entrance fee was $AUD 54 for Cutty Sark and the Greenwich Observatory.  2. I was astounded to see that the entire ship has been lifted off the ground by ~2.5 meters, and is supported by 24 large steel props.

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It really is spectacular.  The fine lines of the hull are absolutely stunning from beneath.  And it has removed pressure from the ageing hull structure, which was sagging from its own weight.   The metal sheathing is Muntz metal, an alloy of copper, used to prevent barnacles and algae from attaching to the hull and slowing the ship speed.  I am unsure whether it has been renewed, or just polished, but as you can see it is gleamingly beautiful.

And speed was what this tea carrying cargo ship was all about.  Each ship load of tea was worth about 6 million pounds, and there was huge competition between the clipper ship captains to be the first home to England with the precious cargo, to get the best prices.

This greyhound of the seas regularly hit 20 knots, and on one voyage from China, averaged 17 knots. (20 knots = 23 mph = 37 kph).  Remember, this is a sailing ship.  Many modern cargo ships would struggle to reach that speed.

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The hull consists of 4″ thick planks, sheathed with Muntz metal, attached to steel ribs.

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Inside the hull, showing the iron frame.

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The lowermost section of the masts is rolled and riveted steel.  Wood above that.

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The masts and rigging are as I remember.  Extremely complex and purposeful.

The intricate woodwork in the captain’s cabin and officers areas, the precisely made steering mechanism, the brass fittings are all as I remember.   This really is a beautiful machine.

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The steering mechanism.  Left and right hand square thread.  Precision metal work.

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And there is a working model of the steering mechanism to demonstrate how it works, for those people who cannot figure it out for themselves. (like me).

 

 

Big Triple Expansion Steam Engines

I knew that the triple expansion engine at Kempton Pumping Station would not be steaming today, but I wanted to see it anyway.

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It is sited next to the Thames, and pumped water from the river up to a holding reservoir.

As I walked to the building I could see the outlines of the huge engines through the windows.

But it was closed!  Damnation!

But, a kind volunteer, hearing how far I had travelled, let me in, and gave cart blanche to wander at will.

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There are two of these 63′ high monsters.  This one has been restored, and is run on steam occasionally, after the boilers have been lit for 48 hours.  The other engine is currently being restored.  The crankshaft of the second one was rotated with the barring engine about half a revolution, after no use since 1985.  Of course it is a triple expansion steam engine, and it now is run on a newish boiler which is gas fired.  Unfortunately the old Lancashire (?) boilers were scrapped.

The interior of the building is also interesting.  The walls are glazed bricks which look like tiles, and there is a 20 ton gantry crane.  The engines weigh 1000 tons each, so must have been assembled on site.

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The walls are glazed bricks.  Note the piston rings on the walkway.

Below the engines are huge water pipes, pumps and valves.

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The space between the triples is occupied by two steam turbine driven pumps, about which more in a later post.  The space was originally intended to be occupied by another triple, which never occurred.   Interestingly, the triples are mirror images of each other, rather than identical, which means that a lot of components cannot be interchanged.  It probably made the plans more symmetrical and elegant.  Very British I suspect.

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Hey, that’s me.  In my tourist hiking gear

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Overall engine height 62 feet (18.9 meters)

 

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Monster big ends and cranks

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HP gauges.  Beautiful artwork hey Frank?!

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And aren’t those column bases works of art?

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Barring engine.  Steam powered

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Those are my fingers against the flywheel, and teeth for the barring engine.

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One of many oil distibutors

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Right on top of the LP

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Piston rod and crosshead

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On top of the world

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Looking down to a big end and the crankshaft

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Big machines need big nuts

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The HP cylinder

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A volunteer pointed out that some of the safety fence posts are recycled Boulton and Watt parallel motion bars!

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check out those cylinder diameters and clearances!

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Spare piston rings

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Piston ring, my finger

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Piston ring join.

I am rapidly running out of posting space, despite many more pics.  So I had better pause.  I didn’t get to the turbine engined pumps.  But I have many more photos…

Let me thank the very kind volunteers who spent time with me to talk about their engines at Kempton.  A marvellous experience.  I must return one day to see them under steam.

Trevithick Dredger Engine at The London Science Museum

I landed at Heathrow at 6am, dropped my bags at the BNB, then caught 2 buses to the Science Museum.  Not jet lagged, but on a high, to see the only intact Trevithick Dredger Engine known to exist.

The room which houses the Trevithick, also contains 4 large beam engines, a Parson’s turbine (of “Turbinia” fame), and a very large 2 cylinder compound.

Disconcertingly, the first atmospheric beam engine, with wooden beam, was partly obscured by a souvenir stall and racks of clothes for sale.  WTF!   Don’t they realise the historical importance and rarity of these engines.  And 3 further moans, to get them out of the way.   The descriptive labels on all items had minimal information.  Nothing like dimensions, power, etc.  The attendants knew virtually nothing about the engines.  And often, items were behind glass or perspex which was reflective, and prevented good visualisation or photography.   To be fair entrance was free, but to get past the entrance desk it seemed pretty clear that a “donation” of 5 pounds was expected, (which I was happy to contribute).   Those complaints aside, I have to say that the collections were fabulous.

I could see the Trevithick at the far end of the room, so to curb my mounting excitement, I forced myself to not rush up to it, but to try to look at every exhibit on the way.

Eventually I was there and it was there in front of me.

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It was one of the smallest engines in the room (The “Energy” hall).  The older beam engines were many times larger, but that was a major reason this engine was so successful..  more power, lighter, smaller, and several times more efficient at converting coal to rotative motion.  No one could tell me why there is a huge divot in the cast end of the boiler.

The con rods, stands, standard cross tie, and chimney are not original, but were added when the engine was restored in ~1875.  But that is now part of its history.

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From that side it was apparent that the main shaft was square over its entire length, something not previously known to me.

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The boiler feed pump was relatively tiny.  I do not know if it is original.

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The firebox has been re-sleeved.  The chimney mount is part of the end plate casting.  And I think that I got most of these items pretty close to right on my model.  Does anyone know what the incomplete flange at 5 0’clock would have been for?

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Note the odd bolt pattern around the inspection hatch.  I got that wrong.  My change to the oblique slide rod stay angle brackets was correct.

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safety valve weight is adjustable.

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Water preheater pipe detail.  Aren’t the square nuts great!

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The throttle restraints are curved, and have fixed position holes for pins.

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Boiler feed tank.  Cast iron.

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Engine supports appear to be cast integrally with the boiler.

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Flywheel hub

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Flywheel spoke detail.  Likely original.

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Chimney mount detail

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Finally (although I do have more photos), a nice view from above.  I do like the crosshead shape.  I wonder if it is original.  Remnants of another Trevithick dredger engine  not currently on display, reveal a wooden crosshead beam.

So there you are.  Fascinating to me.  Interesting enough I hope to you.  I could see no evidence of wooden lagging at all, but i still intend to install some on my model to slightly improve its efficiency.

i have heaps more photos of other exhibits which I may post later.

 

 

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