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.

INSTALLING LATHE LEAD SCREW COVERS

I decided to install lead screw covers on my Colchester Master 2500 lathe.  The lathe is about 50 years old, so you might say that it is a bit late in its life to install covers now, but I really like my Colchester, and the lead screw appears to be in good condition, like the rest of the lathe.   And lately I have been turning some cast iron, which is quite abrasive.  And I occasionally use a tool post grinder.  So, protect the lead screw I bought some covers from DY-Global in South Korea.

To give DY-Global a free plug, the covers arrived at my home in Australia, from Korea, 48 hours after I paid for them.   With a hand written thank you note.  Fantastic service.

Anyway, back to the installation.  I had installed covers on another lathe a few years ago, and I was not looking forward to repeating the experience.   If past experience is anything to go on, the installer is lucky if afterwards he (or she) does not require skin grafts and a blood transfusion.

Handling the covers is like handling an oiled snake, which bites.

So this time, I thought about the job in advance.

And I made mental notes, which I am now setting down, for your benefit.  And mine, if I ever have to repeat the task.  I might add that the covers do not come with any installation instructions.  Nor could I find anything on the web which helped.  So this is how I managed.

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The unprotected leadscrew

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With the carriage moved to the tailstock end

Firstly, clean and oil the leadscrew.  This can be done after the cover installation, but it is a lot easier if done beforehand.

Also, tke note of the dimensions of the lathe hardware where the covers will sit, to make sure that the covers will fit, and not obstruct the leadscrew nut or anything else.

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There are 2 covers for each leadscrew.  Take note of the outside and inside diameters, and the compressed length of the cover.

Then, wearing eye protection and gloves, compress the cover with one hand, while removing the metal clip with the other hand.  Then very carefully, allow the cover to expand to its full length.  WARNING:  the cover is under considerable tension (correction…  Should read “compression”).  Do not allow it to explosively expand.  How do I know this?   Do not ask.

The alternative method is to disassemble the lead screw, half nuts, leadscrew bearing mounts and most of the carriage.  It might be easier to do this, but I did not,  so I will press on with my chosen method.

The expanded cover will be about 1 meter long, depending on specifications.  It will be oily and slippery, and attract whatever dust and crap you have lying around your lathe.  I suggest that you wipe the exterior surfaces clean, to make subsequent handling a bit more like handling a dry snake than an oily one.   Re-oil it after installation.

Lay the cover near the leadscrew, in its intended position.  The carriage should be at one extreme end of the lathe.   You will note a big diameter end and a small diameter end.  In my case I decided that the small diameter should be at the carriage end.

The next instruction is the pearl in the description.  Read it carefully.

Using fingers, prise open the big diameter end of the cover and slip it over the lead screw about half way long the exposed length.  It will resist you, but be forcefull.

Then twist the cover to screw on the rest of it.   Simple!

I found that 95% of the cover went on in a few seconds, but the final 3 or 4 turns of the cover would not go on by twisting.  To get those last turns on, I used small flat screw drivers to lever them on.   Even better, I realised later, would have been to use bicycle tyre levers.

The cover then snaps into place, in a most satisfying manner.

 

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The big diameter end of the cover slipped over the leadscrew.

 

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Screwing the cover on.   Make sure to keep the small diameter coils inside the big diameter ones.

 

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One of the covers in place.  The one on the other side of the carriage is mirror reversed of course.

 

 

 

The compressed cover occupies about 50mm, so the carriage movement is slightly reduced.

The first time I installed these covers took me several hours.  And skin grafts and a blood transfusion.   Now that I have this technique it takes me about 5 minutes.

 

 

Horizontal Mill Engine (HME)

The HME is our Model Engineering Club competition build for 2017.  I finished making the components and tried to get it running, unsuccesfully.

So today I took it to the GSMEE morning meeting, and Rudi, who is a retired marine engineer, and has completed his own HME, took one look at mine and said that the timing was totally up the creek.

Rudi fiddled for a few minutes, and said, “it will work now”.  A couple of other members doubted his assessment, but were not confident enough to put money on it.

Anyway, this afternoon I hooked it up to a small compressor (my air brush compressor actually), and at 10psi it started to move.  At 16psi it was ticking over quite nicely.  Then the big test, throwing it into reverse.  And hallelujah!  It reversed.

Seeing an engine working, which you have made yourself, is an immensely satisfying moment.

This one still has some finishing jobs to be completed.  Like sealing the joins against steam leaks.  And a bit more polishing.   And maybe a name plate.   And there is an annoying knock which might disappear on steam.  But if not, I might need to re-make one of the bearings.

But it goes!!   Yay!!

 

Traction Engine Disappointment

I had inspected a 20 year old traction engine, 3″ scale so about 1.5m long, never been fired, just run on compressed air, and appeared to be in excellent condition.

The seller did not have a price, so after discussing with SWMBO who was surprisingly supportive of my passion, I rang the seller with an offer.  I did not really know what it was worth, but I made what I thought was a reasonable offer.

The seller immediately accepted the offer.

Had I offered too much?

Oh well.  I would press ahead.  I made an arrangement to pay and pick up the engine 4 days later.  I needed some time to get the cash and there was an unavoidable baby sitting day in between.

So 4 days later I hitched up the trailer and set off.  Just as I was driving out the gate, the phone rang once, then a message came through.

The seller had woken up with a bad feeling, and decided to not sell after all.  Asked for a return call.

I was feeling very disappointed and a bit cross, so I did not ring him, but acknowledged the call with a message.

Had I offered too little, and the seller had second thoughts?

Did he really intend to sell in the first place?

A susbsequent email from me has not been answered.

I did consider consulting a lawyer about breach of verbal contract, but there was nothing in writing.  So I am moving on.  Just pissed off.

Now I am looking for another traction engine, preferably requiring completion or repairs.

Wood Heater Paint

Some readers opine that I should paint my workshop wood heater.

Well, I will probably not do that.  Reasons~

1. I quite like that rusty brown look

2. I have a lazy streak

3. I dont have the stove paint, although a friend has offered some free.

4. With use it is changing colour to a darker brown.  Interesting.  Is it a chemical reaction of the rust to heat?

5. Would paint stand up to these temperatures?

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Boxford 125TCL CNC Upgrade

This small CNC lathe was converted from the original c1985 electronics, to components which are compatible with a PC running Windows XP and Mach3.

Reader Paul M asked about circuit diagrams.  I must confess that I do not have such.  Indeed, I would not understand them.  The electronic connections were made by my expert friend Stuart T.   I believe that Stuart intends to write up the conversion for one of the Australian magazines, and possibly this post might give him a gentle shove~.

In passing, I should give Stuart a thumbs up for his excellent CNC lathe program, which is far superior, in my opinion, than Mach3 for running the CNC lathe.  It is called Ezilathe and is available as a free download.

Anyway Paul, here are the promised photographs of the electronic components of the Boxford, after the conversion.  You should be able to work out many of the connections by zooming in.

 

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The Boxford 125TCL sitting on a bought trolley which could have been made to measure.  The PC is on the bottom shelf, the extra toolholders and tools in the drawers, the wireless MPG on the front, and upgraded stepper motors in black.

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The rear view to show the extra power outlets to supply the screen and PC.  I still operate this lathe in a spare bedroom of my house.  Very handy if I have a sleepless night.  It is so quiet that it does not disturb SWMBO.

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The view with the back open.  The only components from the original setup are the spindle motor, the main switch, and the Gemini controller (RHS with orange cover).

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Power outlets, main switch and power supply.

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Transformer.  Can’t remember what the Fotek is for.

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Gemini with cover removed.

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C11 R9 Breakout board, the optical indexer (top), and Gecko stepper drivers (LHS), parallel cable from the PC,  all mounted on an aluminium plate.

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Spindle motor, original.  But now considering upgrading to a more powerful motor.

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new cable junction box for the stepper cables.

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New cooling fan, top LHS

So, I hope that these shots are some use.  If you do not recognise the components, I suggest that you follow my example and bribe an expert friend to do the connections.

Heat in the workshop. Heaven!

Today I fired up the pipe heater which I have welded up over the past few days.

Fantastic!!

I was so keen to get warm on this 10 degree celcius day, that I deferred water proofing the flue.

And of course it rained!

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I forgot to bring some newspaper or kindling, so I used a propane torch to get the wood burning.

Within 5 minutes the temperature of the burner was over 200c, and in an hour it was 350 degrees celcius/ 660 fahrenheit.  Heaven.

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The shape of the furnace accepts wood up to 1400mm long.   The handle at the bottom is the ash tray.  The hefty looking handle above is for the furnace door.   The bit of RHS on the floor is so I can open the door when it is hot.

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This is the external sheath of the flue.  The strip of corrugated iron is to separate the hot internal flue from the cooler external layer.

And then it rained!   And I had not installed the waterproofing fitting to the roof.   So water poured down onto the heater, and filled my workshop with steam.!!

Despite today being only 10 deg celcius, I happily machined away until 6pm.  2 hours later than I usually stop due to the cold.

Then I had to go home to cook dinner.   SWMBO was getting hungry.

Oz is hot. Right? Bloody Cold just now.

It is the depths of winter here in southern Oz.  I know that is difficult for you northern hemisphere types to realise, but here at present we have frosts when we get up, and the workshop is just too cold to do anything productive after about 4pm.

And the tooling surfaces rust up in front of my eyes.

So I decided to make a wood burning heater for my workshop.

The workshop is 7m x 13m.  Not lined or insulated.  Just a tin shed.

Electricity supply is dodgy and expensive.  And I dont want to suck power away from my CNC machines.  Bottled gas is very expensive… about $AUD20-25 per day.

But I have plenty of trees dropping dead branches.

So I decided to make a wood burning heater.

Parameters…..

Not occupying much floor space.  No wall space available.

Able to be removed in warm-hot months (it gets up to 110 fahrenheit  / 45celcius in summer.

So this is what I have come up with.  I had some 220mm dia pipes left over from a building job.  That would be the body of the heater.

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The footprint is 300x400mm.  It is 1600mm high.  There is an ash pan under the grate.  The air intake (hidden) and flue are placed to encourage swirling in the pipe, and maximise heat transfer to the body of the heater.  The top is closed with a heavy plate.  I plan to add a proximity rail.

The heater is now finished, and I will do a test burn tomorrow.  If it works as hoped, I will post a video.

And totally unexpectedly, I have bought a model traction engine.  It feels a bit strange to buy rather than build, but here it is.

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1500mm long.  Deceased estate, never run on steam.  Beautifully made.   based on a steam engine which was used to power a sawmill.  ? 3″ scale.  Needs boiler re-certified. 

I will make a ride on driver’s trailer, and a kids ride on trailer.   I really have caught the steam disease.

TRIPLE FINAL(?) ASSEMBLY

Just one photo to show that I have not totally ignored the triple expansion marine engine.   I have started to re-assemble it, having made almost all of the components.  But there were quite a few finishing tasks put aside until later, which I am now tackling.  eg lubrication points.  I suspect that this will not be the final teardown and assembly.

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The gunmetal base, with main bearings and crankshaft installed.  The eccentrics are not finally positioned.  

And some reminder photos from 2 years ago, of making the crankshaft.

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The centres were drilled on the CNC milling machine, after the locating the top of the bar

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Turning the second big end bearing.  Note the packing to support the crankshaft after the first big end had been turned.   The main bearings were turned last.

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The finished crankshaft.  Not much remains of the 51mm stainless rod.

Model Ship’s Cannon

I spotted this model cannon at the Townsville Maritime Museum, Townsville, Queensland, Australia.  The barrel is cast and bored.  Nicely detailed, particularly the barrel decorations.  My understanding is that such exuberant decorations on the original cannons would have been very costly, and not used on naval ships.  But they were sometimes commissioned by pirates who were spending their ill gotten gains.

The staff very kindly allowed me to reposition it for the photographs, and I am very happy to give the museum a thumbs up for some most interesting displays.

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MMcannon top

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Koffiekop Modification

I have been considering this modification for some time, and today I located the aluminium heat sink-radiator material which I needed, and which I knew was somewhere in my stuff.

The Koffiekop Sirling engine requires differential temperatures between the top and bottom plates.  I wondered if installing some heat shedding plates on the top plate might increase the running time on a cup of coffee.

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The heat sink material is glued to the top plate with a heat transmitting electronic silicone glue.

Afterwards I ran a test with a cup of hot water.

The engine ran for 26 minutes!  That is an improvement of about 25% on the best previous runs.  Success!

The Horizontal Mill Engine (HME) is assembled and ready for the D valve to be timed.  This is how it looks.  I wont get to it for a couple of weeks now.

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I did squirt some compressed air into the valve chest, but minimal movement.  Not surprising, considering the position of the eccentric was just a guess.  When I get it going there will be a video.  That crankshaft pin is temporary.  It is a 3mm cap screw going through a 4mm cap screw.  go figure.

 

If at first you don’t succeed…

Try again.

The small reversing handle lock on the horizontal mill engine took 4 attempts.

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Most of the components are made.  That is my blood staining the plans.  

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The lock is made of brass.  About 32mm long, then bent into shape.

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From the left.. 1. broke when turning the thread.  2, cracked during bending, not enough heat.   3. Too much heat melted the surface.  4. Success.

And on the same subject, the cylinder head and guide went well until I neglected to remove it while finishing the guide block.

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I might have mentioned this one previously.  It still rankles.

Another Diversion from The Triple

My model engineering club (GSMEE) has an annual competition build.  This year it is a small horizontal reversing steam engine.

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So I have taken another break from the triple to build the HME.  I have redrawn the plans to make my model 40% bigger, and also to accept metric fasteners.

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The HME blanks for the base, the cylinder block, the flywheel pillar and the flywheel.  The only stainless steel I had in my junkbox, er storage facility, had a  big hole in the middle, so I filled that with brass.

All was going well, and I spent almost a day making the piston head guide. Then finished off by making the guide rod and block.   I decided to take another thou off the guide block, and set the lathe going.

And heard an ominous bang.

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I had forgotten to remove the piston head guide from the from the piston before I restarted the lathe.  Destruction.  The lump at the bottom is another piece of brass, ready to be turned into another head guide.  I had run out of suitably sized brass, so I silver soldered a length of rod to some square section.  A day later and the new piston head guide is now made.  

At least I know from this (and other crashes), that the second part is always made much faster than the first.

And on a different subject, I recently bought on Fleabay a self centering 4 jaw chuck.

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It does not replace the independent jaw 4 jaw chuck for accurate work, but will be useful for turning small square stock.  Also, I plan to make a backing plate for it to fit into the tailstock, so it will hold taps.

A Base for the triple, and some oil holes…

Thinking about the options for a base for the triple expansion marine steam engine..

I looked at every photo I could find on the net, and thinking about whether I want to be historically accurate, or just really solid, or a bit interesting with an historical flavour.

At this stage, the decision is not set in concrete, but I am going with the last option.  Photos later in this post.

But first, I have pulled all of the major components apart, and I am spending time doing a few of those jobs which I had been avoiding because they are difficult and imprecise, and if they go badly it will be a major disaster at this stage.  Like drilling the oil holes and wells for the big ends.

Nothing precise about this.  The con rods and big end shells and bearings have been painstakingly machined, and I do not want to think about remaking them if I stuff up.  And drilling into curved surfaces, with a 1.5mm drill bit…

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That thread is 3mm dia.  The hole above the nut is the oil way, 1.5mm dia.  Very tricky and too anxiety provoking to be thinking about a video.   Amazingly, it all went well!   I now have 2 oil holes for each of the 3 big ends.  I will need to fill the well with oil with a medical syringe and fine needle, but.

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The crankshaft, turned from stainless steel a year or two ago, and the conrods.  The big ends now with lubrication points.

And here are the major engine components, after partial disassembly.

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At top left is the condensor, then the cylinder block in 2 parts, then the steam supply valve.  The square section tube is going to become the base.  And so on.  You get the picture.  I will count the bits at some stage.

Then I cut and drilled the square section aluminium tube for the base.

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The cast base of the triple, with main bearing studs and column studs in place.  All sitting on the square section alu.  Have not decided whether to bolt it together, or just Loctite it. 

Those holes in the square section were drilled and chamfered on the CNC mill.

 

Making Hubcaps

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I made 5 of these

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The 50mm diameter aluminium blank had a 12mm bolt inserted into a blind threaded hole.  The bolt was held in the lathe chuck.

The 2 short videos which follow show 1. the final rough cut 2. the finish cut.

The shape was drawn as a DXF file using CAD, the G code was generated using Ezilathe, and the lathe was controlled with Mach3.

 

 

Total CNC turning time was 16 minutes per hubcap, plus cutting the groove for the O-ring, then a quick polish with a cleaning pad.

Chariot Racing

Another little job for my CNC lathe.

A fellow club member asked me to turn some hub caps for his car restoration.  And the shape was a bit unusual.

This is the first effort at complying with his request.

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It is aluminium, and will be held in position with an O-ring in the groove.

If I had put a knife edge on it he could have justified new car number plates…..

BEN-HUR

Metalworking for a cabinet maker

Our model engineering club has been locked out of our club rooms because MOULD has been detected in the building.   Apparently a lengthy process to reduce the mould to acceptable levels.  (note to self…. make sure that the inspectors never set foot in our house).

So our meetings have been held in various locations, including a sports centre and a basketball building.   I feel quite virtuous when I enter these buildings, but for some reason I do not feel any fitter when I exit.

A recent day meeting was held at my farm workshop.  Not my farm anymore, just the buildings.

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Not that one….   the other one.

And one of our more senior members requested a display of CNC machining, from design to product.

So, I drew up a finial which was required to complete a bookcase which I had built 30 years ago.  Then imported the DXF drawing file into “Ezilathe”.

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Showing Stuart Tankard, the author of Ezilathe, scrutinizing my drawing ….  and offering excellent suggestions for improvement using Ezilathe.

Then used Ezilathe to generate the G codes…..

Then to the CNC lathe…..

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CNC turning the finial in 51mm brass rod.  1600rpm, 100mm/min.  Controlled by Mach 3 Turn.  I removed the tailstock shortly after this photo was taken, to permit completion of the ball.

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Some GSMEE members watching the CNC turning.  I spent 3 days clearing up the workshop so the 16 members could fit in.   Amazing how much space was revealed in the workshop.   This is the Taiwanese lathe which I converted to CNC.  See old posts for details of the conversion.

I watched anxiously as the part was gradually revealed.  Admittedly, I had had a test run in wood to check the parameters, but this was the first run in metal.

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The finial.  The bar stock was parted later.

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Bookcase finally finished, after 30 years.

If you are interested in CNC lathe work, you should take a look at “Ezilathe”.  It is superb.

If you are on Facebook, (of course you are if you are reading this), you might like to take a look at the GSMEE Facebook site.

 

Arduino Controlled Indexer-2

Most of the bits and pieces have arrived for this project, so I made a start on the machining today.  I used 80mm dia aluminium rod to make the stepper motor support piece.

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Stepper motor (right), flexible 8-12mm shaft coupler, and the rotary table shaft (left)

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I cut a 92mm cylinder of aluminium, squared the ends, centre drilled a face, drilled it out to 25.4mm, shown in this photo.  Note the 4 ribbons of swarf coming off the work.  The drill bit is an industrial stepped bit, with 4 cutting lips. Then the hole was bored to 28.80mm.

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An upside down photo of the stepper motor (left), motor support which is hiding the flexible shaft coupler, and rotary table (right).  Next to drill and tap for the bolts, and provide access holes for the coupling screws.

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And some more milling to convert the cylinder to a rounded square section, then drilling and tapping for the grub screws and bolts for the stepper motor.  (tapping with the Mogens Kilde tapping head in the picture).

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The finished support block

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Mechanicals finished.  Now for the electronics.

Triple Expansion Steam Engine Pipework.

I am close to disassembling the Bolton 9, before gradually reassembling it in preparation for running it on air then steam.  Most of the components have now been made.  Most recently I completed the pipework associated with the Edwards air pump and the twin water pumps.

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This is the combined air and water pumps, and new pipework.  Most joins are silver soldered, but a couple are Loctited.  Loctite should be adequate.  These components will not get super hot.

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This valve is one of the few components on this engine which I have not personally made.  This one came from the effects of the late Harry Close, who was a valued member of our Model Engineering Club.

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The pipework adds to the overall interest , yes?  It will look good when polished.

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And the “tails” for the valve rods, which are attached to their respective steam chests.  The BA7 bolts are a bit oversized for the job.  The intermediate cylinder tail screws into place.  I am not sure why it is different from the other two.

So now I am making a list of tasks which need to be completed when the engine is taken apart, hopefully for the last time before it is run.  The list is not complete, and so far it runs to 3 pages.  Mostly like fixing parts which interfere with each other, and freeing up tight bearings.

I will take some pics of the components.

Cutting a thread up to a shoulder

A problem with some thread dies is that they have such a large “lead in” that they are unable to cut a thread up to a shoulder.

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A 3/8″ x 32tpi die.  Note the large lead in taper.

This results in the thread stopping a long way from the shoulder… undesireable in some situations.

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This is a thread made with the die in the previous photo.  I wanted it to go right up to the shoulder, but this is as close as it gets.  About 2mm gap.

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The screw in this upsidedown photo does not allow the shoulder to seat properly.

The solution?  Modify the tool.

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Here is the tapping die, held onto a magnetic chuck, within a machined steel disc to increase the magnetic attachment force.

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So I ground off the top 1-2mm of the die.  My surface grinder is out of action, so I used the tool and cutter grinder.   A bit rough but it worked.

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This is the die after grinding the surface.  Note that there is no lead in.  I ground the unlabelled face so I did not lose the specs of the die.

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And the screw after using the modified die.  The thread  now goes right up to the shoulder.  Incidentally, this is a zoomed photo using an iphone.  Not bad?

So that does the job.

The downside is that in future the thread must be started with the unmodified side of the die, and finished with the modified side.  Adds some time.  And the die is thinner and a bit weaker.

A pity that the dies are not manufactured with one “no lead in” face.

The particular set of ME dies will now all be modified in the same way.

 

A Turntable for the Triple Expansion Engine.

I have not weighed the Bolton 9 triple expansion steam engine, but I would guess that it is 20-25lb.  (weighed it.  25.5lb)

Access to the various bolt on bits and pieces has become increasingly difficult and tricky, and involves frequent repositioning of the engine.

I removed the bolt on base and that has improved the situation a bit.

Then I had a brainwave, thought bubble, inspiration  whatever, and I tried a ball bearing turntable….   you know….. one of those Chinese restaurant middle of the table gadjets.

It is incredibly useful!

Here are some pics and a video showing it in place;  just a demo of the engine at its current (unfinished) stage.  I think that the turntable might  become a frequently used tool for heavier models.

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The Bolton 9 on the turntable

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And the latest additional bits…   non return valves on the water pumps.