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.

Home Made Ring Roller, and first attempts at bronze brazing.

The two projects for which I am currently accumulating materials, will require rolling copper sheet and rod into circular shapes.

A few years back I made a ring roller to make components for steel gates, and it would have been perfect for rolling the copper foundation rings and fireboxes.

It is fairly heavy duty roller, powered by a 1/2 HP motor, geared down 1:40.  I have bent mild steel up to 1/2″ thick 4″ wide, but I founds its limits when I tried to bend some hardened rod.   It left some grooves in the rollers.   And those grooves would imprint marks into the soft copper, which would be totally unacceptable in the two boiler projects.

So yesterday I disassembled the machine, removed the rollers, and turned the rolling surfaces in the lathe until the grooves vanished.  The 31.75mm diameter finished at 30.4mm.  Nice and regular and smooth.  And working smoothly again.

Pretty mundane stuff eh?  But oddly satisfying.

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BRONZE BRAZING

And after that I tried my hand at bronze brazing joins in copper parts.   The boiler inspector requires that certain joins in the boilers use bronze brazing, instead of silver soldering.  I am now reasonably proficient with silver soldering, and had no experience with bronze brazing.  So, do I try to learn a new skill and use it on my expensive copper components of the boilers?   Or do I pay an expert to do the bronze brazing for me?

Well, I decided to buy some bronze rods and flux, and give the bronze brazing a try on some copper scrap.  The AMBSC boiler code requires the use of Tobin bronze.  Local welding suppliers had never heard of it, but I found a supplier on ebay.

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Tobin bronze is another name for Naval Bronze. (according to my quick Internet “research”).  It is relatively resistant to corrosion, and very strong.  Actually much stronger than silver solder and with a much higher melting point.  Silver solder is said to be as strong as the parent metal, so bronze must be awesome.  Bronze will fill gaps, indeed a V gap is desireable, wheras silver solder prefers an even, tiny space which the solder fills by capillary action.

The brazing rods are available in diameters 1.6, 2.4, and 3.2mm.  I had no idea which size would be best, so I bought 1.6 and 2.4mm.  I also bought some 303 flux powder, even though some experts say that flux is not necessary.  OK, lots to learn.

So, onto YouTube, and watching multiple tutorials on bronze brazing copper.  I reckon that YouTube is fantastic for learning new skills.

With silver soldering, the solder goes to the areas which are fluxed.  But, it seems that when bronze brazing, the bronze follows the heat, so the application of heat is critical.  And not just where the heat is applied, but how much.  The thing is, that the parent metal is not melted in either process (unlike welding).   When bronze brazing copper the temperature range between succesful brazing and melting the parent metal (which means disaster) is quite narrow (about 100ºc), and the brazing temperature is about 950ºc, so it is tricky.

And copper is an excellent heat conductor, so the heat spreads rapidly through the parent metal, with result that the bronze filler spreads and it is difficult to get a good appearance.

Here are the results of my first efforts.

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The copper is 3mm thick.  The bronze filler is not pretty, but this is my first ever effort.  I discovered that you cannot actually see the molten puddle until you have moved on a bit, and by then it is easy to have applied too much filler.

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I cut across the join to check the adequacy of the brazed join.  I was quite pleased to see that there were no gaps or voids.  Also, although the bronze filler looks ugly on the surface, it is actually fairly flat, and should be insignificant when painted.   You can see the V which was prepared in the edges of the join.

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Next I tried an angle join.  Looks neater, but not enough bronze filler at one end.  USB for scale.

OK, looking promising, but what about thin copper?  Will that just melt away?  By the way, my heat source is oxy-acetylene.  I tried MAP gas with air, but got nowhere near enough heat.  Oxy-acetylene burns at 3500ºc and copper melts at 1083ºc so it is not difficult to end up with an ugly, expensive blob of copper and bronze.

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This is 1/4″ pipe with a 0.7mm wall.   No problemo.

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and the final test for the day was end joining the 1/4″ pipe.  The hardest aspect was holding them in position.  Quite happy with this.

I tried both 1.6 and 2.4mm bronze filler rod diameters, and for this scale job I preferred the 1.6mm.  The  joins were significantly lumpier with the 2.4mm.

So, with a bit more practice I think that I might be able to bronze braze where necessary on the vertical boiler and the Trevithic dredger engine.

P.S.  Those readers who know about brazing will get a laugh.  I did the brazing without dark glasses!  None of the tutorials mentioned that dark glasses allow you to see what is happening in the molten puddle.  I found out about dark glasses at my model engineering club club meeting last night.  John.

 

 

 

 

 

Bolton 7

For reader Timothy, I hope that these photos answer your query.

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The Bolton7 was my first attempt at engine building.  As you can see, the finish leaves a lot to be desired.

Another Use for Magnets

I purchased some bronze disks for use in the model Trevithick dredger engine.  The disks 204mm diameter had been bandsawn off rod.  I had specified minimum thicknesses of 7mm and 12mm.  One disk was 9.2-9.7mm thick and the other was 12-15mm thick.

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The bandsawn blanks of LG2 bronze.

In preparing the disks for machining I filed off a few protrusions, and using a straight edge, identified the valleys and ridges.

The thicker disk was held in the 3 jaw chuck and both faces were turned flat with no problems except avoiding the needles which were thrown off in a wide arc around my lathe.  Final thickness 12.5mm.  A persisting divot should be able to be avoided in the final part.

The thinner disk needed to be packed out from the jaws of the chuck by 4-5mm in order that the lathe tool  cleared the jaws during machining.  In the past I have used machined packing pieces, but it is always a fiddle to hold the workpiece, the 3 packing pieces and the chuck key in only 2 hands.  Today I had a brainwave.

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I used rare earth magnets!

I tried to measure the thickness of the magnets, but they are so powerful that I was not confident that I was getting accurate readings.  So I just used them and measured the thickness of the finished workpiece.

I am sure that this idea is not original.  But it is to me.

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Here is the thin workpiece held in the 3 jaw, and packed away from the chuck by rare earth magnets.  Of course the magnets are attracted only to the jaws, and not the bronze workpiece, which helps, but I will try this on steel later.  Should work for magnetic metals also.

After machining both faces I took various measurments of the workpiece thickness.  The measurements in mm were 8.73, 8.68, 8.69, 8.72, 8.70, 8.72.   Not perfect, but not too bad at all.   I wonder if I might have improved the measurements by surface grinding the magnets.  I wonder if the chuck and its jaws are contributing to the variation.  It was certainly an easy method.

If the workpiece had been thinner I could have increased the thickness of the packing by doubling up the magnets.

For those who are following the Trevithick Dedger Engine build, the bronze was not cheap.  The 12-15mm disk was $AUD90 and the 9mm disk was about $AUD80.  From George White P/L, Melbourne.  I will be nervously trying to not muck up the machining.

A New (to me) Tool

One aspect of our weekly GSMEE meetings (Geelong Society of Model and Experimental Engineers) is that I learn something new at every meeeting.  The exposure to new information is not too surprising considering that our group has members who are or were a machinery designer, mechanical engineer, CNC operator, marine engineer, aircraft mechanic, a quarry operator, gun enthusiasts, a fireman and various other areas of expertise.  Even a bee keeper.  And even a retired gynaecologist.

Recently Neil brought in a boiler which was assembled but not yet soldered.  And it was held together with spring loaded clamps the like of which I had never before seen.  Some other members were also very interested in the clamps, which are, apparently, extensively used in aircraft panel assembly and repair, and also in car body work repairs.

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Neil’s boiler end plates, clamped together.

The clamps are called CLEKOS or CLECOS.  They are easily applied and removed and are reusable.  They are used for temporary joining of materials to facilitate marking, drilling, riveting, soldering, welding or gluing.  Exciting to me because I can see many applications in model engineering and wooden toy making.

The Clecos come in a variety of sizes and configurations.

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This Cleco requires a 1/8″ hole, and will join materials up to 1/2″ total thickness.  This type joins 2 or more pieces of material which have a hole drilled as small as 2.5mm up to 5mm.  The range of hole sizes may be larger than I am aware.   Only one face of the materials needs to be accessible, so the Cleco can be used to fasten material to a closed container such as a boiler.   It is spring loaded and requires a tool to apply and remove it.  Application and removal is very quick.  Any materials which will accept a drilled hole can be used-  metal, wood, cardboard.  It would not work with easily compressed material such as foam rubber.  The application pliers are available on Ebay and are inexpensive.

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This spring loaded Cleco looks particularly interesting.  The clamps are small, have clamping thickness of 20mm and a reach of 1/2″ to 1″.  Again, they are not expensive ($AUD7-11), and very quick to apply and remove.  Surprisingly powerful grip would be quite adequate for gluing or riveting or soldering.

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Some Clecos do not require the application pliers but use a wing nut.

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And others use a hex nut.  Anyone know why there is a copper surface coating?

The Clecos are surpisingly inexpensive.  On Ebay I have seen the spring loaded fasteners as cheap as $AUD1 each, and the pliers at $AUD15.    I bought a kit comprising pliers and 20 fasteners for $AUD49.  Ebay UK has the best selection and many have free postage.  The range on US sites is good, but postage costs assigned by Ebay are astronomical.

(A reader has commented……

The Clecos and other skin pins are colour coded, silver 3/32, copper colour 1/8; Black 5/32′ gold 3/16 brown 1/4…..     thankyou “someone”.)

 

 

Trevithick Dredger Engine Flywheel

You must forgive me for rushing this blog.  I do feel rather pleased to have made a start on the Trevithick Dredger Engine.

The first part for the TDE was waterjet cut from 6mm mild steel.  I emailed the DXF drawing Tues, it was cut out Wed and picked up today.  Impressive service from Colin and Sandy at Waterjet Geelong.    340mm diameter.  The finish of the cut is so good that some light filing and rounding the sharp edges is all that will be required.  I will machine the bore hole after the shaft is made.  The magazine article is my workshop copy.  It will not remain this pristine for long.

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The thinness of the flywheel is a Trevithick characteristic.

Buying Copper Pipe for Model Boilers

My next 2 projects require 150mm (6′) copper pipe for the boilers.  The Trevithick dredger engine will operate at only 30psi so the wall thickness needs to be only 2mm thick to comply with the AMBSC regulations.  But the other project, the vertical test boiler will operate at 100psi and the copper needs to be a minimum of 2.5mm thick, or preferably 3.0mm or 3.2mm.

I had purchased a 350mm long x 2.8mm wall thickness piece of 6″ copper pipe at an engineering club swapmeet, so I thought that would be OK for the test boiler, but when I examined it closely I noted some scribed lines from the previous owner’s intended project.  There were also some drilled holes, but they can  be used or filled.  The scribed lines were unacceptable, so thinking that they were not very deep I carefully skimmed the cylinder surface on the lathe.

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The headstock end is held lightly in the 3 jaw chuck.  The tailstock is centered in a piece of fitted Delrin.

Taking off 0.05mm per pass, and using a sharp Diamond lathe tool (from Eccentric Engineering), when the marks finally were removed, the wall thickness was down to 2.45mm, just below the minimum thickness for the test boiler.  Bummer!  I can use that piece for the lower pressure Trevithic engine, but what to use for the test boiler?

So I contacted every Australian copper pipe supplier that I could see on the Internet, every model engineering vendor, and visited every plumbing supplies vendor in my region.  2mm thick pipe is available but nothing thicker.  Then to overseas suppliers.  Eventually I located some at MaccModels Engineering Supplies in the UK.  £7.67 per inch for the 3.2mm x 6″.  So my 12″ piece will be almost £95 ($AUD190) plus postage.  I took the opportunity to stock up a few other sizes which I will need for the 2 projects.  Postage came to $AUD170.   A bit painful.

So, to end this expensive story, my 3.2mm thick copper pipe is on its way.  I do feel a bit guilty about the Avgas being burnt to get it here, the kilogram x kilometers of air pollution and CO2.  And the annoyance that it is quite possible that the copper ore was mined in Australia, but I had to go to the other side of the world to buy a bit of the manufactured product.  Or is copper still mined in the UK?

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Gradually accumulating the materials.  The copper sheets and disks are 3mm thick.  The square section rod is for the boiler foundation ring.  I don’t want to start cutting until I have all of the materials.

The OTHER NEXT PROJECT

In the previous post I showed the boiler which I am intending to build.

In this post I will show you the steam engine which I also intend to build when I have AMBSC approval and I have accumulated the materials.  I have discussed the plans with the boiler inspector, and am in the process of redrawing the plans taking into account the required modifications so it can be run at public exhibitions.

It is the TREVITHICK DREDGER ENGINE, at 1 in 8 scale.

This was designed by Richard Trevithick, and made in 1806,   It was the first high pressure steam engine.  It also employed a steam blower, cylindrical boiler, safety valve, and many other innovations.  Incredibly, the engine worked in its first iteration.   Richard Trevithick was indeed a genius, although relatively unrecognised in his own lifetime, and for almost 2 centuries since.

Here is the earliest drawing which I could locate of the dredger engine.

It is from an encyclopedia which was published in 1818.

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This is a drawing of a Trevithick dredger engine which was reconstructed in 1885, with some errors, including the bent connecting rods..   Of particular interest is the piston-cylinder assembly which is partly encased by the boiler to minimise heat loss. The large, thin, flywheel is a characteristically Trevithick feature.

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The Trevithick engine as reconstructed, and as it is displayed in the London Science Museum today.  The blacksmiths who formed the domed boiler end, pentrated by the cylinder assembly must have been incredibly skilled.

The Trevithick Dredger Engine was drawn at 1:16 scale by Tubal Cain in 1987, and modelled by him. His plans were published in “Model Engineer” magazine.

It was redrawn by Julius Dewaal at 1:8 scale and published on the Internet in 2016.  The plans are currently freely available on Google Images, as 9 pages of A3 plans.  The plans are beautifully drawn, but require some modification to comply with current AMBSC regulations.  I am currently redrawing the Dewaal plans with the necessary modifications.  When they are approved I will detail the modifications.  A 1:8 scale the flywheel is 340mm diameter (13.4″).

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A schematic drawing of the engine, as it was reconstructed.

So, watch this space.  Getting the plans finalised and the boiler approved will take some time, as well as gathering the materials.  From my preliminary discussions with the boiler inspector I will need to learn how to braze in bronze, and I will document that process.  Finding a supplier of phosphor bronze in the required sizes is proving difficult, and I might have to settle for the nicer to machine, but weaker, LG2 bronze.  If any reader knows of a supplier of cold rolled phosphor bronze sheet 200mm wide and 6-8mm thick, I would be delighted to hear about it.

Triple retrospective

This post is for reader Roy, who asked how the triple expansion engine columns and base and cylinder blocks were aligned, and also about joint sealants.

To be honest, I did not really remember the details, but the posts on or close to Feb 2015 include the following photos.  The aluminium plates were precisely machined keep the column faces exactly separated by the final width.  The plates were bolted to the columns, then to each other.   I lined up the join in the plates with the center of the main bearing housings in the base plate.

The longitudinal alignment with the cylinder bores was determined by the precise drilling in the tops of the columns, and the cylinder base covers.  And a little longitudinal movement in the crankshaft allowed for a few thou discepancy.

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And this is what I used to steam proof the joins.  I used no gaskets.  The Loctite 567.  It was recommended by an expert friend who uses it on full size steam engines (thanks Tom!).  The Loxeal 58.11 is also excellent but it sets very hard, and is very difficult to separate later.

 

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BOILER FOR MODEL STEAM ENGINES

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

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

This is what I have in mind….

boiler assembly

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

The certification process here in Australia requires the following steps:

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

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

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

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

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

Small Tube Bender

 

I have recently been busy installing a steam powered water injector on the 3″ Fowler traction engine.  Involved quite a few bends in 1/4″ copper pipe.

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Some of the new pipework on the traction engine.  Since this photo, I have also made the winch functional.  (pics of that in future post)

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Hand pipe benders.

I was not totally satisfied with the regularity in the bends, or the straightness of the runs in the pipe.  That provoked some discussion at our model engineering group, and one member (Stuart T) showed us the pipe bender which he had made some years ago.

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Pipe bender designed and made by Stuart Tankard.

 

As you can see it has a  heavy duty frame,  shoulder bolts holding the rolls with machined slots for various sized pipe, and a 19mm hex connector for the driving battery drill.  A demonstration of pipe bending on this machine convinced me of its superiority to the hand held benders

Fortunately for me Stuart still had the plans which he had drawn up, so I made my own bender.  I made a couple of changes to Stuart’s design.  I made a 1/4″ hex on the driving screw, to accept the commonly used connector for battery drills.  And I did not have any suitable bronze for the main bush, so I made a brass bush, which incororated  a thrust ball bearing which engages during the bending procedure.  Probably unecessary but it was there in my junk drawer so I used it.

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The radius of the bend in the tube is determined by the radius of the roll.  1″, 3/4″ and 1.5″.  Each radius has grooves for 1/8″ 3/16″ 1/4″ 5/16″ 3/8″ and 1/2″ tube.  Since then I have also made 2″ rolls.

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Aluminium rod for the rolls.  

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Using a bearing to centralise the tailstock end before center drilling.

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The lathe tools used to make the grooves.

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3 rolls turned from each length, with an allowance for parting.  Then drilled and reamed, and parted in a lathe big enough for the 2″ bar to be securely held.

 

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Completed bender.  The wooden box keeps the components organised.  Not a tribute to the craft of wood working but it will do.   The vacant pegs are for 2″ rolls which are yet to be made.

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The raw materials for the tool.  1″ X 3″ and 1″ square mild steel, and 1/2″ silver steel.

The bender is held in a bench vice.  The bending process is quick and controllable using a variable speed battery drill.

The symmetry of the rolls (as opposed to the asymmetry of the hand held tools) means that the centre and the mid point of the bend is totally predictable.

Since then, I have made some further changes in the design of the pipe bender.

  1. I have added some feet so it sits squarely on the bench and does not require a vice for support, although it can be held in a vice if preferred.  The tool is quite heavy, so small jobs can be managed without a vise.
  2. I drilled and threaded some extra holes, to accept 2 rows of 3 rolls.  See the photo below.  That pipe bender has now become a pipe straightener.  I made some extra rolls, so now there are 6 rolls of the 2″ size.  As long as the 3 rolls in each row are identical, the rolls in the 2 rows can be different for the straightening process, but ideally there should be 6 rolls for each pipe diameter.  Straightening copper pipe is easy, as long as there are no kinks or very sharp bends, and the copper must be annealed.  The pipe should be approximately hand straightened, cut to length plus about 2″, then pulled through the rolls which have been adjusted so the rows  are almost touching.  3 or 4 passes, with some rotation of the pipe each time results in a near perfect straight pipe.   Any slight residual bend can be eliminated by rolling the pipe on a flat surface.
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Some extra threaded holes added pipe straightening to the tools functionality.

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Two rows of rolls are needed to straighten bent pipe.  So I made 3 extra wheels in 1/4″ and 3/16″ sizes.  Later I realised that the extra three rolls do not have to be identical diameter to the first three, as long as each triple are identical.  The tool straightened this bend quite nicely, although with some experience, I would now probably hand straighten it a bit before putting in the tool. 

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After 2 or 3 passages.

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And some rotation with each pull through

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The copper does have to be annealed to get a good result.

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And to put a bend in that nice straight tube…  some shuffling of the roll positions….attach the drill (slow speed setting)

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And a quick and easy bend. 

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Pretty good

 

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The underside.  Substituted cap screws for grubscrews, so the tool sits flat on the benchtop.  quite adequate for light bending jobs, but straightening needs a vise.

 

Scale Traction Engine – installing a steam powered boiler injector.

My 3″ Fowler R3 Traction Engine boiler can be filled with a hand pump from the tender tank, by a crankshaft powered pump from the tender tank, or by a battery powered electric pump from the driver’s trailer.   The full size original R3 (see previous post for photos) has a steam powered injector, which uses boiler steam to suck up water from the tender tank using a venturi effect, then using black magic passing the steam+ water through some cones, increases the pressure which forces the mixture back into the  boiler.

Here is a link to a YouTube site which sort of explains how the black magic works.

And this is the steam injector on the full size R3 Fowler.

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And this is the injector which I bought for the 3″ scale Fowler.

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It is a vertical injector, with connections for 1/4″ (6.35mm) pipes.  But I did not use it because it protruded too far underneath the tender.  So I have used an identically sized horizontal injector, which is shown below, during installation.  The full size original also appears to be horizontal.   The black fitting connected is the water inlet valve.  The control handle will extend above the rim of the cockpit.

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The red thing is the winch, and its driving disk.  Winch engaging pins have never been completed, another job for later.  The rear wheel has been removed.  The injector pipework passes between the winch drum and the hornplate, with just enough clearance.  Running the pipe around the brake axle seemed like a good idea at the time, but I am not so sure now.  When painted black it will not look so odd.   The water connection with the tender tank is yet to be made, as is the steam supply connection.  A few more hours.

How to time a Model Triple Expansion Steam Engine

The daunting aspect of timing the triple delayed the completion of mine by at least 6 months.  In the event, it was not difficult.

If timing a steam engine is not a particular concern of yours, I suggest that you turn off now.   Otherwise this will be particularly boring.  This post is in response to a request by a reader.

The engine needs to be pretty much completed and assembled.   Everything fitting.  Crankshaft rotating.  Valve rods tightened.  Stephenson’s reversing mechanism assembled and working. Cylinder drains installed.

Next I suggest that you make or buy a 360 degree protractor, and attach it to the crankshaft at the high pressure end.  Like this.

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Note that top dead centre (TDC) of each piston is marked (H,I,L), there is a pointer, big marks at 120 degree intervals, and identifiable marks at 10 and 5 degree intervals.  I added a rotation arrow later, because it is easy to mistake clockwise and anticlockwise directions when making adjustments.

Next, decide where in the cycle you want steam to be admitted.  On expert advice from a marine engineer who is also a model engineer, I decided to admit steam at 10 degrees after TDC. (thanks Rudi!).  I also decided to cut off admission of steam at about 70% of the  power stroke. (pretty standard).

The easiest valve to time is the low pressure valve.  It is on the end of the engine.  It is the biggest, and there is not much engine stuff getting physically in the way.  Despite that, I decided to start with the high pressure valve.  It also is on the outside end of the engine.  The reason is that I wanted to follow the passage of the steam flow, in order to understand what was happening.  Each cylinder is timed separately, independently.  So the order is, high pressure, intermediate pressure, low pressure.  Forward direction first, then reverse, for high, then F & R for IP, then F&R for LP.

The timing is adjusted by 1. changing the distance between the crankshaft and the valve, usually by adjusting the length of the valve rod and 2. by changing the position of the eccentric on the crankshaft.

Firstly, the valve must move equally over the steam inlet slots. (the top and bottom ports). The point at which the inlet slot starts to open is noted on the protractor for both steam inlet ports.  The number of degrees before or after TDC is noted for the top port, and the procedure is repeated for the bottom port.   For the bottom port Bottom Dead Centre (BDC) is the reference point on the protractor.  The angle should be identical for TDC and BDC.  If it not identical the length of the valve rod needs to be adjusted.  On my machine, that was done by adjusting the nuts holding the valve rod to the valve bracket, but it could be the valve rod to the eccentric strap.

Determining the point at which the steam inlet port starts to open is easy.  Remove the valve chest cover, bolt the valve chest to the cylinder block, and rotate the crankshaft by hand until the port is obviously visually open.  Cut a sliver of paper 5-10mm wide, (I used copy paper), measure the thickness of the paper (0.1mm in my case), insert the paper into the open port, rotate the crankshaft to close the port until the paper is jammed, then while applying tension to the paper, slowly rotate the crankshaft to open the port, until the paper just starts to move.  At that point the port will be open by the thickness of the paper.

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The valve cover is off, a sliver of paper is pushed a centimeter or so into the port, the crankshaft is rotated to jam the paper then the crankshaft is rotated in the direction that is being adjusted until the paper is just released.   At that point the port is open by the thickness of the paper.  I calculated that 0.1mm was equivalent approximately to 3 degrees of crankshaft rotation.  So whatever was displayed on the protractor, I subtracted 3 degrees to get to the exact point of port opening.

when the valve moves exactly equally up and down over the steam entry ports, the point of opening is noted on the protractor relative to TDC of BDC, depending on which is being measured.

The eccentric grubscrew needs to be loosened, and  rotated on the crankshaft to bring the point of port opening to 10 degrees past TDC.  Then the grubscew is tightened.  BDC will automatically be correct if the centering process has been done accurately.

I had bored a hole in the eccentric strap to allow access to the grubscrew from underneath the engine.  That meant that the crankshaft had to be in a certain position to allow access to the grubscrew, not necessarily TDC or BDC or whatever.  That does not matter.  What matters is that the eccentric is rotated a certain number of degrees on the crankshaft.  I did this by using the Allen key to loosen the grubscrew, then using the Allen key to hold the eccentric fast, while rotating the crankshaft.  Then tighten the grubscrew, being careful to not move the eccentric.   The measurements need to be rechecked of course.   With practice, it is not difficult, and can be accomplished first go in most cases.

If this all sounds complicated and difficult, it really is not.  But I did need to make a record of every step and measurement and direction.

For the intermediate cylinder, the HP cylinder block needs to be removed.  The HP valve chest can be retained, just swung out of the way, retaining the previous settings..  You have to be careful, but this method does save a heap of bother.

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One thing I would suggest.  When the opening points of both IP inlet ports are determined and set, I suggest that before the HP cylinder block is reassembled, that the IP valve rod is measured above the IP valve chest.  And that the measurements are recorded and placed in a secure vault.  Those measurements can be used for any future adjustments of the IP valve, without the time consuming and very fiddly necessity of removing the HP cylinder block.

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I have determined the opening points for the intermediate cylinder using the paper method.  With the depth micometer on the valve rod above the valve chest, I am measuring and recording those positions, for possible future use.

And I have a confession.  The next photo shows the HP upper cylinder drain, and the same view at top dead centre.  As you can see, at TDC the piston blocks the drain.)!*!)  Read on.

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There is another method for determining the opening point of the valves.

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Plastic tubes are pushed on suitable points for the cylinder to be set, in this case the HP. The valve is pushed against the valve face, in this case with rubber bands.  One blows into the appropriate tube while rotating the crankshaft.  When the port starts to open, you can hear your exhaled breath coming through (if your hearing is OK, which mine is not).  The protractor reading is recorded, and used as before.   Note:  the drain cock passages MUST NOT be occluded by the piston at TDC or BDC.  In my case, this proved to be a problem, hence the use of the strip of paper method.

So, I hope that this is of some use.  If my description is jaberwocky, please send a message and I will try to help.    John.

First taste of steam for the MODEL TRIPLE EXPANSION ENGINE

I made a video of this first run, but I am experiencing great frustration uploading it, due to our totally pathetic Internet speeds here in Australia.  I will include it later in this post, but the resolution is way down.  I will upload a higher res version next weekend.

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Stuart Tankard’s superb gas fired vertical boiler, was also getting its first run powering a steam engine.

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We did not connect the condenser until later.

OK, so here is the video.  Again, apologies for the low res quality.

Model Triple Expansion Steam Engine. First taste of steam tomorrow!

I was very excited to see my triple running reasonably well on air recently.  But it was tight, and required a decent gutful of air pressure to turn it over.  But it did go!

Then it seized.

The cause was the intermediate cylinder valve rod seizing in its guide.  Probably a bit tight,and not getting any oil.

So I have loosened the gland, installed a displacement oiler, and made and installed a flywheel.  I also finished the pipework around the condenser.

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Displacement oiler top left, brass flywheel, and pipework.  The condenser on a marine engine would have been cooled with seawater, pumped with a separate pump, but I have used the 2 pumps on either side of the Edwards air pump.  In future I might install another pump.  The book “Marine Steam Engines and Turbines” has been been very useful.  

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I just like all of the brass and copper and components in this picture.

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The flywheel is too big for the scale, but my model does not have the weight and momentum of a propeller shaft and propeller, so a sizeable flywheel seemed appropriate.  Later I will add some gear teeth on the flywheel and a cranking handle on a removeable pinion, which some medium size engines had to assist with cranking to a starting position.  

So, tomorrow I will hook my triple up to Stuart Tankard’s vertical boiler, and see what happens.  I am sure that steam leaks will be revealed.  Hopefully there will be a video worth posting!

TRIPLE EXPANSION MODEL ENGINE- FIRST RUN (air)

This is a short video of the first run of the Bolton9 Model Triple Expansion Steam Engine, which I have been building on and off over the past 3 years.

The video is a bit shakey, because it is taken on my hand held phone while I am using he other hand to operate the controls.  I really did not expect the engine to work!

It runs a bit roughly, and is still quite tight, but settles down in the final few seconds.

It is not running very smoothly, because it is on air rather than steam, and because it is probably only powered on the high pressure cylinder, and maybe a bit on the intermediate, and not at all on the low pressure cylinder.

The next day it would not run.  Very frustrating.  I suspect that one of the eccentrics slipped on the crankshaft, and threw the timing out.  Not the easily accessible low or high pressure valve, but the intermediate one, which needs another teardown to get to it.

But Hey!  It will work.  I can see the light at the end of the tunnel.

One of my readers has requested a description of the triple engine timing procedure, so that will appear on this blog soon.  Unless you have a particular need for the timing info I suggest that you give that post a miss.

Geelong Vintage Machinery and Classic Truck Show – day 2

The oiler on my traction engine failed today, so I did not run the teaction engine, and I had some time to look around the other displays.  The oiler failed due to some grit in the non return valve, easily fixed when I got it back to the workshop.

As always at this annual show, the trucks and classic cars are fabulous.

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Ford truck, with Caterpillar Traxcavator as load.

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Mercedes truck with a startling colour scheme.

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Must have been more than  50 magnificent trucks in the lineup.

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This is an original engine from a WW2 Liberator bomber.  It was run for a few minutes twice daily.  Must have been heard by the entire city.  Absolutely awesome sound.  I cannot imagine what 4 engines on a plane would sound like.   1300HP!   An entire Liberator airplane is currently being restored nearby.

 

All weekend, tractors were competing in a tractor pull test.  The load gradually increases, with the tractor pulling with all it its might, until it runs out of either power or traction.

The smell of diesel fumes, and the noise,  was magnificent.

 

And my favourite, of course, was the mighty R3 Fowler.  In this instance effortlessly powering a large pump.

Geelong Classic Truck and Vintage Machinery Show. Day 1.

I was busy minding the 1:4 scale Fowler traction engine today, at the show, but these were a few items which were of particular interest to me, of the hundreds on display.  Not to mention the tractor pull, the Liberator WW2 engine demo, and the magnificent vintage trucks and cars.

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Peugeot 403.  My first car was one of these.  For its day it was reliable, rugged and advanced.  Won the first Redex rally across central Australia in 1956.

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Marshall Compound traction engine on low loader.  The traction engine is completely original, unrestored.  Needs a lot of work.

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Marshall smoke door

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Marshall engine

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Marshall pressure gauge

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Marshall, from the driver’s position.

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Fowler R3 and baby R3

Back to the Triple Expansion Steam Engine

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I installed these cylinder drains on the triple, but was not satisfied with their appearance because they looked too big.   So I bought some of a different pattern from Reeves UK.

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The new cylinder drains are smaller, and have a handle which is suitable for joining all 6 drains to one control handle.

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The new cylinder drains are a more realistic scale.  I suppose that I should have made them myself.  

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From above.  Getting them to line up was a fiddle.

 

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The crankshaft protractor now has a (temporary) pointer.  When the timing is finally adjusted, the protractor and pointer will be removed.  I am planning to make and install a crank positioning gear and pinion and lever.

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The crank positioning gear and pinion shaft on the full size, ship’s triple expansion steam engine at The Geelong Showgrounds.  It is on the low pressure end of the engine.  I will make something like this to act as a flywheel on my model triple.

More Wierd Stuff

Since my “Strange Lights over Geelong” experience I have been looking at all sorts of weird posts on YouTube.  UFO’s, crop circles, megalith structures, evidence of buildings on the moon and on Mars.  There is a mountain of information out there, and while a lot of it is lies and rubbish, some is harder to dismiss.   It is not inconceiveable that Governments have information which they are witholding from the general populace, about aliens, UFO’s, ancient civilisations and so on.  Indeed, there are YouTube interviews with ex astronauts about UFO’s on the moon, and ex government ministers and officials about UFO’s and aliens, and Rothwell.  It may well be that the current increased talkativeness is due to a recognition by governments that they can no longer keep a lid on the previously secret information, so they are gradually allowing people to talk.

One line of posts which I have followed is evidence that something is going on in Antarctica.

And one source of information is Google Earth.  One post related to a strange set of giant “steps”.  I checked on the post information by checking the coordinates in Google Earth.

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Look at the middle of the photo.  That series of “steps” does look unusual.  You can check on this yourself by entering the coordinates on the photo into Google Earth.   The “staircase is about 2.5km long, with each step about 250 meters.

Anyway, to continue with my story, as I was zooming out from this point, I noticed a bright shape about 138km towards the south.

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The object which caught my eye was the white rectangle above the word “Coast”.  This section of Antarctica is directly south of Western Australia.  The rectangle is about 380 km from the coast.

And this is what shows up on Google Earth as I zoomed in.

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The image is from 1999.  The black rectangle is 21 x 7km…  Quite a size!   I am unsure what the bright white is.  Possibly sunlight reflecting off a shiny surface.  Or a rough attempt at concealing the rectangular area?    This is at latitude 70.2 S, longitude  87.2 E.

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Also, there is a faint streak from the rectangle heading about 100km to the east.  It is also 7km wide.     The staircase area is also visible to the north.

So that is it.  I can find no reference to this structure, but if anyone knows anything about it, please enlighten me.   If you have any interest in this weird stuff, you might the posts on YouTube by SecureTeam10 worth watching.

I am heading back into the workshop tomorrow.  Installing a steam powered boiler water injector on the Fowler traction engine, and bit by bit, finishing the triple expansion engine.

I have installed the new AC Servo motor to replace the spindle motor on the Boxford 125TCL CNC lathe, my expert friend Stuart Tankard has wired it up and reconfigured Mach3.  I am delighted to report that it has vastly improved the CNC lathe.  Will post some pics in a day or two.

A New Spindle Motor for Boxford 125TCL CNC lathe.

The spindle motor on my 33 year old Boxford CNC lathe has struggled to machine steel, although it copes with brass OK.  My expert friend has recently upgraded his machine (identical to mine) with a new spindle motor, and I will do likewise.

The new motor is a 750 watt Servo, bought on Ebay from China.

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It is more powerful than the original DC motor, small enough to fit the limited space in the 125TCL, and my friend reports that it is performing very well indeed.

Some modifications to the mounting system and drive pulleys and electronic controls will be required.

For reader Tom, who is upgrading a 125TCL as a school project, I include the following photo.

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On-off switch of the 125TCL.