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.

CNC Mill Upgrade -4

I removed the old XY & Z axis servo motors from the mill.  Each one weighs about 15kg (33lb).

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The old servo motors.  The X and Z were working fine.  The Y was faulty, but I do not know whether the fault was in the motor, the encoder, the controller, or the connecting wires.  I will put them on Ebay as 2 working, one for parts.

Then I removed the belt drive pulley off each motor.  There was a grub screw, which would not budge.  Assuming that it had been Loctited, I applied some heat, judiciously.  The grub screw came out, but the pulley would not budge, so a little more heat, and a gear puller.   Two of the gears came off, but one still would not budge.

I asked for advice, and I was loaned a different type of gear puller. (thanks Rudi).  This time, some movement of the gear on the shaft was noted, and eventually the last motor gave up its gear.

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This one worked.

The shaft of the old motors was 16mm diameter.  The new motors had 19mm shafts.  So I spent some time on the lathe boring out the gears to fit the shafts of the new motors.  The keyways of the old motors were 5x5mm, and the new ones were 6x6mm.  So, I borrowed a 6mm broach (thanks Stuart), and enlarged the keyways in the rebored gears to 6mm width.   The new keyways needed a lower profile, so some time on the mill and surface grinder  to reduce the thickness of the keys to 4.5mm.

That was quite a few peasant hours hours on the lathe, mill, and surface grinder, but the end result was good.

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The new servo motors, with the timing belt gears fitted, with keys in place.  I will set each motor in place on the CNC mill, determine the final exact position of the gear on the shaft, then indent the shaft for the grub screw.  Then, when I am sure that all is correct, the gear, grubscrew and shaft will be Loctited.

Another small issue was that the boss on the new motors was 5mm deep compared to 3.5mm deep for the originals.  So the mounting plate for each motor needed the recess to be deepened by about 1.5mm.

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I used a boring head on the mill to deepen the first one, but it did not produce a good finish, so the next 2 (shown) were deepened on the lathe, in a 4 jaw chuck.

Meanwhile, back to the rats nest in the electric control enclosure….

 

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The bare space top left is where the old servo controllers lived.  They were removed.  Then I spent a half day tracing each wire from the controller to the old servo, and removing it.  That produced a carton full of wires.  The rats nest is now a little less tangled.  A lot more of those wires will be removed as the job progresses.

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The new servo controllers bolted into position.  They are fatter than the originals, so a bit of rearranging was required.  The yellow box top right is the main spindle speed control (VSD) which is being retained.

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And on the right hand side, newly bolted into position today, from the top down, are the smooth stepper, the C11 breakout board, and two C10 breakout boards.   Awaiting some expert wiring.  (Stuart, are you reading this?)

 

Upgrading the CNC mill -3. Moving a threaded hole in steel plate.

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this is the new Y axis servo motor, sitting on its mounting plate, after the old servo has been removed

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Unfortunately the existing M8 threaded holes in the mounting plate are just in the wrong position for the new motor’s 8mm mounting holes.

So, do I 1. make a new mounting plate and assembly?   2. machine or file the new motor’s holes to fit the old plate?   Or 3. Fill the old mounting plate hole, then drill and tap new holes in the correct position  ??

  1.  seemed a lot of work   2. would have looked ugly and probably voided the motor’s warranty      3.  Seemed tricky, but I decided to give it a go.   If unsuccessful I could always revert to 1.

Filling the old holes.  Could have used steel thread and silver soldered it into place.  In retrospect, would probably have been the best option.   Could have used steel thread and Loctited it into place…. decided against, in case subsequent machining  softened the Loctite.   Could have filled the old holes with bronze, and drilled and tapped new threaded holes….   well, for better or worse, that’s what I decided to do.

The new holes impinged about 25-33% on the old holes.

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The old holes were bronzed.   I improved my technique as I moved around the holes.

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After cleaning up on the mill, the new holes were center drilled 

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Then drilled to size, and tapped.  revealed that the bronze did not entirely fill the voids. 

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I wondered if the bronze would accept a suitable degree of tightening of the M8 cap screws, but all seemed fine.   Note the jacking bolts, to prevent distortion of the weldment in the milling vice.

The bronze-steel sandwich did cause the tapping drill to wander slightly, but not enough to cause concern.  Next time I will try silver soldering in a steel filler piece.

Meanwhile, I have been removing parts and wires from the electrical enclosure.

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The servo controllers are removed.  Bit of a rats’ nest hey!  About 90% to go…

 

Installing the lathe gear

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I neglected to take a photo of the completed gear.  In this shot it is almost finished.

I intended to reassemble the spindle and its cluster of gears, spacers, and taper roller bearings myself, but after talking to an expert on the topic (Swen Pettig), I realised that sometimes it is better to leave surgery to a surgeon.

I gratefully accepted Swen’s offer to help.  In his working  life Swen had performed this task on many, many occasions.

Firstly Swen reinserted the taper bearing outer races in the headstock.  The lathe spindle is approx 80mm diameter and 800mm long so it is heavy.  After carefully cleaning, it was fed into the headstock, progressively loading the bearings, gears, spacers, clips and nuts, and moving and tapping them down the shaft as it was moved into place.

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Note the photo prints to remind us of the order of reassembly.  Board to protect the lathe bed.  Repaired gear laying flat.  Surgeons’ towels blue rags.

when it was all reassembled and tightened, the retaining disk at the chuck end was loosened, sealed with liquid gasket (Loctite product- cannot remember the name), and retightened.

Then Swen went through a lengthy process of checking the end play, using a dial indicator, tapping each end of the shaft with a copper hammer, and finally settling on 0.01mm of play.

Then we had a short test run at low speed, and he tested the end play again, with no change.

Then we set it running at 200 rpm, and went and had a cup of coffee for 20 minutes.  Came back and checked the bearings temperatures.   All cold, all good.

I reinstalled the external gears, the cover, etc, and took some decent cuts in some cold rolled bar.

All good.  Oil change soon.

 

German Battleship Helgoland – book review.

Seaforth Publishing, in association withThe National Maritime Museum Greenwich, is publishing a series of books of plans and history of famous warships, in this case the Helgoland.

GERMAN BATTLESHIP HELGOLAND

Detailed in the original builders’ plans

By Aidan Dodson

 

Wow!

I opened this large format, hardcover book of ship plans at midnight, expecting a quick flip through, and was able put it down 3 hours later.   But I will be returning.

The first 20 pages outline the development of German dreadnaughts and their wartime careers and fates, and a fascinating history it is.  The ship structure, armament, machinery (including engines), protection, pumping systems and damage control, and fire control are described in a degree of detail which was satisfying and not overwhelming to this non expert but interested reader-reviewer.

Then, all but 20 of its 144 pages are reproductions of the original builders’ plans of the WW1 German battleship Helgoland.   The plans are detailed, and beautiful and fascinating.  With original annotations in German, translated and explained in the margins.    The 940 x 290mm centre fold of the longitudinal section is just stunning!

Modelers, historians, ship aficionados, and anyone with a vague interest in battleships will love this book.  I certainly do, and eagerly await further volumes in the series.

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Front jacket

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Centerfold.  

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The German navy used triple expansion reciprocating engines rather than pay royalties to Parsons to use turbine engines.

CNC Mill Upgrade -2

The major components arrived this week, from China and USA.  Switches, and other components which go “ping” will be bought locally as required.  I am hoping that existing pulleys, belts, brackets will be adaptable.

The motors to drive the X, Y and Z axes are 1.2kW AC servo motors which can be connected to single or 3 phase power.  Each one weighs 6.7kg (14.7lb) .  From China, they are nicely finished.   Substantially shorter than the old servos which they are replacing and slightly larger diameter.  I am hoping that the slightly larger diameter will not cause major problems.

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AC servo.  There are 3 of these.  Kitchen knife to open the box and for scale.

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Old Y axis servo on the right, and the new AC servo left.

 

And each servo motor came with a controller and cables and connectors.

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And the electronics came from USA.

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C11 breakout board.

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C10 breakout boards x2

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And the Smooth stepper control board.  It is tiny, but the most expensive electronic component.

All up cost so far is ~$AUD2100, of which shipping is about 25%.

Next step is to swap over the servos.  The old shafts are 16mm and the new ones are 19mm.  I intend to machine the bores of the pulleys.  Hope there is enough meat  Tofu to allow that.

Cutting the Gear

Today Swen and I started cutting the gear.  Here is the setup.

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The gear was centered on the rotary table with an aluminium bush, which fitted the outside of an ER40 collet chuck.  The chuck had an M3 shaft which fitted neatly into the spindle of the rotary table.  3 bolts secured the gear blank to the T slots on the rotary table.

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This photo was taken after the setup was broken down.  Showing the M3 taper ER 40 collet holder, which I used to centralise the gear blank on the rotary table.

I started the mill conservatively at 200 rpm and a 0.5mm deep cut, but gradually increased the RPM to 450, and the depth of cut to 2mm.   Later adjusted to 300rpm, 1mm cut.

The CNC table performed flawlessly, with rapid advances between the 360/77º degree cuts (about 4.6º each tooth).  The feed rate was controlled by manually winding the X axis feed on the mill.

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We initially used water soluble cutting fluid, but changed later to raw Tap Magic, which seemed to work better.

As you can hear in the following short video, the cutter teeth are slightly off centre, but working well.  Didn’t quite finish the gear teeth in this session.  Some sparks later on, indicated that a cutter sharpening was required before the finishing run.  That will happen tomorrow.

The smoke is evaporation of cutting oil.

The setup will be left undisturbed by removing the gear cutter for sharpening.

I changed my mind about sharpening the cutter in the middle of the job, and continued cutting.

Instead, I lowered the spindle rpm, and the feed-rate.  The sparks stopped.  Maybe I was just pushing too hard, or maybe there was a hard spot in the metal.  Anyway, I finished the cuts.

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The finished gear cut.  Are those teeth looking a bit skinny at the peaks?

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Showing the setup from the operator’s view.  The CNC table worked brilliantly.

 

 

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Removing the burrs with wire brush and file.

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And testing the fit with a trial run in the headstock.  Thanks Swen, for helping (actually directing) the trial run.  The new gear on the left.

I made a video of the gear being rotated through 360mm, perfectly, but for some reason it will not upload.  (did upload eventually.. see below).    It looks perfect, with a tiny amount of backlash.   Full installation in a day or two.  I was quite surprised that making the gear to the specifications worked so well.

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Me, testing the backlash.

And afterwards, sharpening the cutter on the Quorn T&C cutter grinder which I made a few years ago.  An amazingly versatile tool.

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Just in case I need to make another.

The lathe headstock will be properly reassembled in a couple of days.  But I am finally feeling a bit confident about this job.

 

 

 

Not Antarctica Again! Groan…

For those readers who have not automatically skipped this post after reading the title, I had some time to spend on Google Earth Pro recently, and back to my area of interest, at the big black reflective rectangle 22 x 7km, photographed in 1999.  And the strange 300 x 150mm objects seen 2006 – 2007.

This time I went back a few years to 2002, and this line of objects caught my eye.

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This is Antarctica, Dec 31 2002.  The red, yellow and blue pins are 300 x 150m objects, seen 2002-7.  The big black rectangle is in the middle of the left hand cluster.   The area of today’s interest is the small red line to the left of the long red line.  The small red line, placed by me on the photo, is 20km long.   The next photo is zoomed in to the small red line…

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Still 2002, small red line. Those 21 black dots are 1km apart.  And there is another, to the right near the top of my red line.   Now to zoom in some more…

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Look at those shapes.  They are 300 x 300m each.  Similar but not identical to each other.  Exactly 1 km apart.

The black rectangle does not appear in these 2002 photos.

The co-ordinates are bottom right, so you can check this out for yourself.  What do those black shapes look like to you?   Unfortunately zooming in closer does not increase the clarity.

Now, do you want to know how I found this second row of objects?  This is where it gets even more interesting.

There appears to be a track or mark in the snow leading away from the big black rectangle, leading to the south east at heading 112º.  The track is 7km wide, the same as the black object.   I followed it on Google Earth, until it disappeared after 132km.  At that point on Google Earth I scanned the years 1984-2016.   And zoomed in and out.

And guess what!  That point is exactly where the row of 21 objects which are 1km apart, starts (or ends).   WTF?!

And just to complete this post, there is a site on YouTube which I have been watching with interest, called “Bruce Sees All”.  “Bruce” is an amateur astronomer with a decent telescope which he has been pointing at the moon, and making videos.  I have taken some screen shots, which I post here.  Hopefully this will stimulate some of you to go to the YT site and check it out for yourself.

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No scale unfortunately, but that white donut shape must be many kilometers wide.  And by the shadow which it is casting, it is way above the surface.  Similar shapes nearby.

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And look closely at all of the rectilinear shapes in this screenshot.  Square meteorites perhaps?

 

I will get back to gear making tomorrow, hopefully.

Preparations for gear cutting

Almost ready to cut the lathe gear.  It is 237mm diameter, 25mm thick, with a new rim Loctited and Scotch pinned to the old hub.

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I borrowed the 6-12″ Mitutoyo micrometer from a GSMEE member.  Thanks Rudi.  I had to learn how to read an imperial micrometer.  The rim is glued and pinned to the original hub.

And today I made a tool holder for the new-old gear cutter which I purchased from Russia.  It was meant to have a 27mm bore, but when measured was closer to 27.1mm, so I made an arbor to match.

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The cutter on the new arbor.  It required 2 attempts to get acceptable dimensions. It will be held in the vertical mill with an Er40 collet chuck.  It runs true.   Not bad for an ex gynaecologist hey?   Might need to sharpen the teeth on this old-new cutter.

Meanwhile, on advice from Swen, another GSMEE member, thinking ahead, and setting up to trial fit the new gear after it is cut.   Here is Swen, making some steel temporary bearings to try the new gear on the shaft, after the gear is made.  Tapping out the old taper bearing races.   This is what Swen did for a living when he was in the work force.  I have learned heaps just watching Swen doing his stuff.

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I admit that I would not have been brave enough to do this.  “Piece of cake” says Swen, tapping out the race with a copper drift.

CNC rotary table and preparing a gear blank

Hi readers.   Sorry for the long break.  Since my return from UK I have been severely jet lagged, then very busy, and not much time in the workshop.

The jet lag going westwards to from Oz to UK was minimal, but after the homeward trip it took 2 weeks to start feeling normal again.  It is a 22 hour flight, plus 2 hour stop over in Singapore.   I do not remember ever having such marked jet lag before, and  not much was done during those initial 2 weeks.

When I did venture back into the workshop, I discovered that my CNC mill was malfunctioning.  The Y axis has been a bit unpredictable for quite a while.  I found a broken wire and fixed it, but the problem returned.  After a previous electronic failure in the Z axis, my CNC expert advisor, Stuart,  suggested that I should  replace the electronics in a major upgrade.  The mill is a solid industrial machine, mechanically in sound condition, and is worth spending some time and money on.

It is a 1997 model, and the memory in the CNC motherboard is a whopping 7k!  I was able to get a fair bit done with the 7k, and the situation was improved by linking an external PC, and using V-Carve Pro.  But there was a limitation in that the mill is a 2.5 axis machine.  Not that I want to use 3 or 4 axes very often, but the lure of improving the mill is irresistible.

So I am in the process of ordering 3 new servo motors.  They will be AC single phase servos, rather than 3 phase motors.  I have installed one of these in my small Boxford lathe as a spindle motor, and it has proved to be reliable, compact, powerful and inexpensive (well, fairly inexpensive, comparatively speaking).  They have been ordered from China.  Cost-wise, the three axis motors will be much less expensive than one of the existing 3 phase servos.  On top of that I will need a breakout board, ESS smooth stepper to link to a computer, and various switches, wiring, power supplies etc.

I will document the steps of the rebuild.

But the item that I was getting to, was hooking up my rotary table to CNC.  I had expected to pick up a new gear for my big lathe on my return from the UK, to replace the one with the broken tooth.  I was pretty annoyed to learn that the gear maker had not done the job, and worse still he had not notified me that it had not been done.  Since he never answers the telephone, I drove to the factory, expecting to pick up the new gear, as arranged and promised, to be met with apologies and excuses.  Long story, I have decided to make the gear myself.

It has 77 teeth, an unusual number for a gear, which means that it has to be made, not purchased off the shelf.  I have a dividing plate with 77 teeth, but I could see plenty of potential for making mistakes using that, so I elected to finish the CNC conversion of the rotary table which I had started last year.  The mechanical aspects had been finished.  All that was required were the electronic hookups.   Fortunately for me, I have a friend who is an expert at these.

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In the center is the rotary table, an 8″ Vertex.  The stepper motor is a NEMA 36.   The intervening aluminium block is the coupler.  The controlling program is Mach 3.  Originally I intended to use an Arduino, but it seemed more complicated and less robust than this setup, which involved using the breakout board of the CNC lathe (right), and a new Gecko driver. (see next pictures)

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Looks complicated and messy.  Much better with the doors closed.  The rotary table Geckodrive is the one on the left.  The 2 on the right are for the lathe.  The black white and green wires 8,9,10, are from the breakout board.  The black and red 1 and 2 are from the 48v power supply, and the stepper motor power is from Windings A and B, 3,4,5,6, in the thick white wire.

I confess that I have little understanding of the wiring.  Stuart had it hooked up in under an hour.  A bit longer configuring and tweaking Mach 3, and it was working.  The extra Geckodrive, and some wires were the only extra components required to make the electronic connections.

I shot a video of it working, with giving a commentary.  But it is so bad that I will reshoot it, and add it to this post in a day or 2.   Sorry.  Not done yet.   But I have been busy preparing the blank for cutting a new gear.

I decided to retain the hub of the gear and to add on a new ring which will be machined, and then new teeth cut into it.

Firstly I had some 25mm steel plate water jetted approximately to size.  I chose water jetting in preference to laser cutting or oxy-acetylene cutting to avoid any inadvertent heat hardening.

I also had the original gear water jetted to remove the outer 25mm, including the teeth, because it had originally been heat treated hardened, and I did not fancy machining that on my other lathe and maybe breaking more teeth!

It was not cheap.  But a nice finish, which machined easily.  So the hub and the blank ring were machined with a 0.1mm gap, and glued together with Loctite 620.  Then Scotch pins were inserted.   Since my CNC mill is out of action, I reverted to calculating X and Y co-ordinates, using FS Pro.  See screen shot below.

 

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My CNC mill is out of action, so I reverted to doing some XY calculations on the manual mill with DRO, using FS Pro.   Screen shot above.

 

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And in the above shot, I have drilled and threaded some M6 holes and Loctited in some M6 grub screws.

Then machined it to size,

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The 6mm holes are the Scotch pins.  The 10mm holes are to attach the assembly to the CNC rotary table for cutting the teeth.

So, this post might be a bit ramshackle and disorganised.   A bit like my workshop at present, and possibly my brain.  My GP has started me on blood pressure medication, so I will blame that.

Watch this space for cutting the gear, soon.

 

Google Earth Antarctica Photos

Google Earth used to update the Antarctica photos annually, on 31 Dec each year.  BUT NOT SINCE 2016.

WHY NOT?

What is going on down there?

CNC Mill Upgrade

I was not planning any more major projects for 2019, instead intending to finish the triple expansion engine, the beam engine, the vertical boiler, and the CNC rotary table.

But… my hand has been forced.

The Y axis on my CNC mill has been a bit unpredictable for some months, and on my return from UK, it has totally stopped working.  It seems to be the encoder on the Y axis servo.  I could just repair or replace the encoder, but after discussing the situation with my expert advisor Stuart, I have decided to replace all of the electronics in the mill.  New axis motors, new breakout board, new drivers etc.  It is a 1997 model, and this is the second electronic failure this year.  Plus, it is only a 2.5 axis mill.  It will move in only 2 directions per move….   XY or XZ or YZ,  never XYZ in a single move.   Plus I would like to add a rotary axis, making it a 4 axis machine.

The in built computer in the mill has a 7k memory.  That’s correct, 7000 bits.  I have an external computer linked to it, which makes it a bit more useful, but the Fagor controller is clunky and idiosyncratic, and I would like to switch to Mach 3.

So, I will document the upgrade as it happens.  The mill is a good solid machine, with big ball screws, and 1000mm of x travel, 450mm Z and 450mm Y.  It is worth spending some money on it.  There are a lot of big, old, CNC machines with obsolete electronics out there for sale.  It will be a project which might just be worth watching.

Showing the handwheels for XYZ axis movements, including the broken X axis handwheel

 

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.

johnsmachines.com

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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.

 

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