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.

Tag: steam engine

Drag

Not what you thought.

Today I made the rest of the drag links for the triple expansion steam engine, and just for fun I made one spare.

I ran out of BA10 nuts.  Ordered more.  1.6mm thread, 3mm overall diameter, 200 of them weighs nothing.  But if I drop one, that is another 25 cents down the drain, because individually they are invisible.

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Drag Links for Reversing Mechanism on Triple Expansion Steam Engine

A bit more progress today.

I spent the whole day making these drag links, and I was pretty happy with the result.

Then I realised that I need 6, and I had made only 3.  (well there are 3 cylinders you see).

So you know what I will be doing tomorrow….

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The drag links are the 3 items with the bearings at the ends, and the connecting rods.  Those rods are 1.6mm diameter (1/16″ inch), and the nuts are BA 10

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I dropped 2 of the nuts.  Gone forever.

Steam Engine Oilers

Knowing that I have an interest in CNC machining, Tom, from the Vintage Machinery Club in Geelong asked me to make a pair of oilers for a very old Wedlake and Dendy steam engine.  The engine is a large (to me anyway) stationary engine, which is run on steam several times each year.  The oilers for the cross slides were missing.

We searched the Internet for pictures of W&D steam engines, but could find no pictures or diagrams of the oilers.  So Tom sketched a design, and I drew a CAD diagram.  The dimensions were finally determined by the materials which I had available…  some 1.5″ brass rod and some 1.5″ copper tube.

This is the almost finished product.

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Just needs 1/4″ BSPT fittings and and oil wick tube so they can be fitted to the engine.

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The copper tube silver soldered to the brass cylinders (top), the brass blanks for the lids (bottom) and the mandrel to hold the assembly (bottom centre) during CNC turning and drilling.

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The mandrel to hold the body (left) and the mandrel for the lid (right).  The cap screw head and hole in the mandrel have a 2 degree taper.  The slits were cut with a 1mm thick friction blade.

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Rough turning the base.

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Turning the lid.  The mandrel is held in an ER32 collet chuck

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Engraving the lid.  Using a mister for cooling and lubrication.  16000rpm, 200mm/min, 90 degree TC engraving cutter.

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The oilers work by wicking the oil from the reservoir into a tube which drains through the base onto the engine slide.  When the wick tubes are fitted the oilers can be fitted to the engine.

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The 1865 Wedlake and Dendy

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1865

My lathe is a Boxford TCL125, using Mach3.  The G code is generated using Ezilathe.

Below is a link to an oil cup from “USS Monitor”, of American civil war fame.   One of the first ironclads, powered only by steam.

http://www.marinersmuseum.org/blog/2010/04/one-oil-cup-down/

(ps. The  lathe which I was converting to CNC was the subject of previous posts and is now working, but needs some guards fitted and a bit of fine tuning.)

OLDEST STEAM ENGINE- Model

Hero of Alexandria, in Roman Egypt, described a steam engine 2000 years ago.  He is credited with inventing the first steam engine, although it is very likely that he was just describing something already in existence as previously described by another Roman, Vitellius, a hundred or so years earlier.

Today I saw a working example of a Hero type engine, and it was much more impressive than I expected.  One of our club members has built 2 Hero engines, and the following video  shows one of them working.

I think that I will have to make one to show the grandchildren.

Click on the arrow to see another grossly amateurish video.

Incidentally, Emperor Nero, who hated his mother, put her in a ship which, as planned, fell apart when afloat with mummy dearest on board.  Unfortunately for Nero she could swim.  What is really interesting is that the ship is described as having some sort of mechanical propulsion system.  Maybe steam??

 

BACK TO THE TRIPLE

It seems months since I made any progress on the triple expansion steam engine.  It is such a complicated build, at the limits of my abilities (or maybe beyond the limits), and many  components have been partly made and put aside to be completed later, that I was unsure just where I needed to resume.

But, Xmas/Saturnalia, New year, several exhibitions, several competitions, and an intervening Stirling engine build all conspired to “force” me to put aside the difficult triple build.  Then it was just too bloody hot to venture into the workshop.  But we now have some milder weather, and I have some free time, so back into the workshop to inspect the triple and see where to resume.

I decided to do some easier components, to ease back into the build.  So I started by making some of the steam pipes,  CNC’d the flanges, and silver soldered them.  Only to discover that there was inadequate access to tighten some of the flange bolts.   So a quick redesign of the flanges to use only 2 bolts per flange, CNC’s some more flanges, removed the bad’uns, and silver soldered the new ones.   All good now, except that I need to fill some unused threaded holes in the cylinder castings, and drill and tap some new ones.

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Checking the fit of the copper pipe, prior to machining and soldering the flanges

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The pipes with flanges all made and ready to be fitted.  Except that these 4 hole flanges had to be replaced with 2 and 3 holers.

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Inadequate clearance to fit the bolts.  So the flange was replaced with a 2 holer.

 

Today I made the bearings for the yokes on the Stephenson’s reversing mechanism.  These are made of gunmetal, quite small (9.5x8x4.7mm), need some precision drilling and reaming, and there are 12 of them.

After considering the “how to” options, I decided to use the recently installed 5C collet chuck on the lathe, having machined the gunmetal to fit neatly into a 3/8″ square collet.

The following pics were uploaded and the order was totally mixed up in the process.  From previous experience I know that trying to re-sort them will result in chaos and losses, so I will leave them as is.

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This is the final photo.   The 14 bearings (including 2 spares) are threaded onto a bright steel rod and the side decorative waist is milled.

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Showing one of the reversing mechanisms, with 4 new gunmetal bearings bolted into position.

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The square 3/8 x 3/8 lathe collet, about to accept the bar which has been accurately sized, drilled and reamed.   I used a parting tool to cut off the bearing at the correct thickness.

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Parting.  The blade is only 1.5mm wide.

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One of the yokes, with bearings bolted in place, and 2 loose bearings about to be fitted to the other yoke.

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precision drilling the bolt holes (1.8mm diameter) using the high speed spindle on the mill, at 6000 rpm.

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The three pairs of valve eccentrics, and reversing mechanisms.

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This should be the first photo.  It shows the gunmetal bar machined to size, drilled and reamed, ready to be drilled for the bolts, then parted on the lathe.

Steam Powered BBQ Rotisserie.

I want one of these on my back verandah to run the BBQ rotisserie.

Seen in the Vintage Machinery Shed, at The Geelong Show.

Click on the arrow to see the driving mechanism.

 

Beam Engine, First Run on Live Steam

My Bolton 12 Beam engine is being exhibited at The Geelong Show in the next few days, along with other model engines from The Geelong Society of Experimental and Model Engineers (GSMEE), and many other full size antique engines.

I am particularly excited by this event, because it is an opportunity to run my beam engine for the first time on live steam.  Plus it is a really great event generally, (see blog from this time in 2014).

We set up our model engines today, in preparation.

The video below, is of my beam engine’s first run on steam.  The Vintage Machinery Society has a full size boiler to run a full size marine triple expansion marine engine, and many other steam engines, including the models in our “cage”.

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The Cage in the Vintage Machinery Shed.  Not sure whether it is to keep the hordes out or the old blokes in.  (Actually, the machines become very hot when running on steam, so the cage is to keep small hands out).

The steam is at 25-30psi.  Enough to turn over the engines, which are just ticking over, not under working loads.

Click on the arrow in the video box, to see the video.

Making Small Gaskets

My Bolton 12 Beam Engine is a steam engine, but to date, has run only on compressed air.

Compressed air, is invisible. Any leaks, might make some noise, and show up as a dirty oil leak, but are not visible to a casual observer.

In contrast, steam shows up every leak.

Our club is having its annual exhibition at The Geelong Show, in 2 weeks.  (See the post from 12 months ago about The Geelong Show)

Steam is available so I have decided to show my Bolton 12 beam engine, and to have it running on steam.

That has required making a steam connection and removing the compressed air connector, And more importantly, making every joint in the steam-air line,  steam proof.

So every join has been opened and a gasket inserted.  Some of the gaskets are oiled brown paper, and some are more permanent “liquid” gaskets.

Making the gaskets was a new and interesting experience, so I decided to make a photographic record.

I made the gaskets from brown paper.

I required 6 of these small gaskets, and 2 larger ones.

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More components ready to have gaskets installed

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Step 1. Make an impression of the surface in the paper using finger pressure.  Do not allow the paper to move.

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Step 2.  Continuing to hold the paper securely, locate the bolt and steam holes using a pin.  

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Step 3. Using an old centre drill, enlarge the pin holes. Rotate the centre drill anticlockwise to avoid tearing the paper. Push the the drill firmly while rotating it, and continue to hold the paper firmly against the surface.

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Step 4. Use the fine scissors to remove the dags. A delicate touch is required.  Use the ordinary scissors to cut the outline.

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It looks like it should do the job.


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The reassembled beam engine.  The displacement oiler, and rope driving pulley have been added since the last photos were posted.

Amazingly,  after reassembly, I had no left over bits.  If it works on steam as planned, I will post a video.  Watch this space.

Stephenson’s Link Rods

The rods for the Stephenson’s links have been turned, threaded, silver soldered to flanges, and bolted to the eccentrics.  Still more to go.  A lot of time and effort for such small parts!

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3 pairs of yokes and eccentric rods, threaded, ready for silver soldering.

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The eccentric, rod and yoke, all joined.

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3 pairs of eccentrics and rods, one pair for each cylinder. 7 machined parts each, so far….

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Triple Eccentrics, 4th attempt success.

The eccentrics are turned from 2 bits of brass, which are separated later.  It was a trial and error effort, mainly error.

I tried soldering the parts initially, but mistakenly used silver solder.  All was well until I tried to melt the solder, and so much heat was required that the thin brass parts were wrecked.

Next time I used Loctite, but during turning, the parts flew apart and were again damaged.

Finally, I Loctited the parts, then bolted them with the final bolts, then turned the disks.  This method worked, but the 6 disks required almost perfect dimensioning on the milling machine during drilling, then the lathe for turning and parting.  Altogether, very demanding.

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Attempt one, showing the brass rod blanks which I soldered then turned, then separated, then discarded.

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Final run, showing the glued and bolted brass rod, and the turned and part parted disks

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Parting the disks was nerve racking, due the fine tolerances, and the eccentrically placed crankshaft hole. But it occirred without disaster

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Final cosmetic facing in an appropriately small Unimat hobby lathe.

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The finished eccentrics, stored on a piece of 10mm silver steel. There is less then 0.5mm between the bolt head and the machined edge.     Hooray!!!!

JOINING DARK PLACES

Today I spent a couple of hours drawing CAD elevations of the high pressure cylinder steam passages, then generating some G codes for the CNC centre drilling, drilling, and tidying up of the steam passage connection to that cylinder.

Then I spent 30 minutes or so running the programmes.

All went well.  No drill bits broken in the depths.  No break throughs of dark passages into the cylinder bore, or into the bolt holes.  Whew.

The steam passages now open into the top and base of the high pressure cylinder. Intermediate and low pressure cylinders to be done ? tomorrow.

The steam passages now open into the top and base of the high pressure cylinder.
Intermediate and low pressure cylinders to be done ? tomorrow.

This is the drilling setup. I used a sine vice, sitting on gauge blocks, to produce an exactly 5 degree angle, to avoid the cylinder bore and the bolt holes.  The sine vice was held in the milling vice.

This is the drilling setup.
I used a sine vice, sitting on gauge blocks, to produce an exactly 5 degree angle, to avoid the cylinder bore and the bolt holes. The sine vice was held in the milling vice.

BOILER PAINT

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

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

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

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

Triple Condenser Covers

The condenser covers are attached to the condenser body with BA7 screws.  The 4 inlets/outlets are drilled, surface machined, and screw holes tapped ready for the pipes.

The condenser covers are attached to the condenser body with BA7 screws. The 4 inlets/outlets are drilled, surface machined, and screw holes tapped ready for the pipes.

An unintentional ding from the milling machine chuck will need to be repaired before painting.

An unintentional ding from the milling machine chuck will need to be repaired before painting.

Covers for the inlet/outlet perforations were made, to enable testing for leaks.  No leaks found.

Covers for the inlet/outlet perforations were made, to enable testing for leaks. No significant leaks found. Slight weeping from the right hand cover will be stopped when the join is sealed or a gasket installed.

SILVER SOLDERING SUCCESS.

In the previous post I described my attempt at silver soldering the condenser unit.

The 29 joins on one end were quite water tight, but the other end leaked like a sieve.

I decided to try to fix the leaky end, by doing the following….

1. I shortened the copper tubes which were protruding more on the leaky end, thinking that the deep narrow spaces between the tubes might not have become hot enough during the soldering.

2. I used a Dremel to enlarge the spaces between the copper tubes.

3. I watered down the flux to make it more runny, in an attempt to get it into the narrow spaces.

4. I used a larger oxy-acetylene tip, to deliver more heat onto the job.  I think that maybe (as per reader John’s suggestion) I was getting intense heat at the soldering point, but maybe not enough into the base metal of the condenser.  The condenser is a thick brass, heavy object, and maybe, maybe it just was not hot enough.  With the bigger heat delivery, it did show the dull red heat which is recommended for silver soldering.  Also, I used a lower silver content rod (45%), again reader John’s suggestion, because it melts at lower temperature, and is less viscous, than the higher silver content rods.  Thanks John!

End result….

The condenser unit, after today's soldering fix.  Note: there are no air bubbles rising!  It is air-water tight, at atmospheric pressure.  That is enough, because it is a low pressure unit when in use.

The condenser unit, after today’s soldering fix. Note: there are no air bubbles rising! It is air-water tight, at atmospheric pressure, which is adequate, because it is a low pressure unit.IMG_2766 (1)Then I glued the end covers onto the unit, using Loctite, in preparation for the next step, which is drilling and tapping the holes for the BA7 bolts which will hold the end covers in place.

THE CONDENSER- not so easy afterall.

I had deferred making the steam passages (in the triple expansion steam engine), and moved sideways to an “easier” task, which was making the condenser unit.

It consists of a gunmetal box, with walls ~4mm thick, ends of 3mm brass, and 28 copper tubes soldered to the brass plates.  Plus end caps which required some milling and drilling ( see yesterday’s post).

I could not find my soft solder, so I used silver solder.  That was mistake 1. The heat source is an oxy actylene torch, and to keep the heat down I used a small tip. Mistake 2.  The end plates were first soldered (that is soddered if you live across the Pacific ocean) to the main body, and that seemed OK.

Then I fluxed the holes in the end plates, and fluxed the copper  tubes and positioned them into the end plates (mistake 3).  In view of what happened, I suspect that much of the flux was wiped off while pushing the tubes into position.

The water tubes silver soldered to the end plate.  The first end soldered, and it had multiple leaks...

The water tubes silver soldered to the end plate. The first end soldered, and it had multiple leaks…

The second end silver soldered, and it was perfect!  No leaks, looked neat.

The second end silver soldered, and it was perfect! No leaks, looked neat.

So, one end soldered without a hitch, and the other needs to be re-done.  Why?

3 possible reasons.

1. The copper tubes protruded further on the bad end, and it was more difficult to position the soldering rod in the in-between joins.

2. I used more heat on the good end.

3. It is likely that the flux was retained more on the good end.

So I am maintaining a well exercised tradition of learning from my mistakes.  I am sure that I have made mistakes 2 and 3 only a few times before.

So how to fix the leaky end??

1. Apply more flux and solder to the leaky bits?  Tried that.  Didn’t work.

2. Expand the copper tube ends with a tapered drift?  Tried that, and it helped, but still not enough.

3. Disassemble the leaky end by melting the silver solder and re-doing it?  After trying fix 2, I think that I have prevented this option.

4. Use soft solder to patch the leaks?  Not yet tried, but that is next.

If fix 4 does not work, I plan to remove and remake the tubes and end plates and re-solder the entire unit.

DARK PLACES

My decision to procrastinate with respect to the steam passages has worked, I think.  Several suggestions have come in, and I am intending to go with the one from Stuart.  And that is to angle the steam passages, which lengthens one on which I can use a larger diameter milling cutter, and to shorten the one under the steam port.  See the red lines for the proposed changes.

Red line plan alteration in the high pressure steam lines.  The other cylinder plans will be altered also.

Red line plan alteration in the high pressure steam lines. The other cylinder plans will be altered also.

While waiting for a light bulb to switch on regarding the dark places, I have not been idle.

I moved on to a part of the triple expansion steam engine build which I expect to be easier.  And that is the condenser unit.

The condenser is the box shaped protuberance attached to the columns.  I believe that its function is to convert the last dregs of steam, after driving the 3 pistons in succession, into water, for re-use in the boiler.

These are the components, machined and ready for assembly.

The condenser components.  There are 28 tubes, to be soldered into the holey brass plates.

The condenser components. There are 28 tubes, to be soldered into the holey brass plates.

The holes in the end plates have 0.5mm of material between them.  Tricky drilling, but a breeze for the CNC mill.

CNC drilling the end plates.  Centre drilling initially.  The 112 operations proceeded perfectly.  Did I say before that I love CNC.

CNC drilling the end plates. Centre drilling initially. The 112 operations proceeded perfectly. Did I say before that I love CNC.

End plate holes.  No breakthroughs, despite only 0.5mm between holes.

End plate holes. No breakthroughs, despite only 0.5mm between holes.

An end cover after machining.  The bosses and holes were CNC'd.

An end cover after machining. The bosses and holes were CNC’d.

ACHLUOPHOBIA or ATYCHIPHOBIA?

The Bolton 9 triple expansion steam engine build has stalled, and it is all due to achluophobia

Achluophobia, in case you are not fully aware of the term, is fear of dark places.

The next step in the build, is to drill or mill  the steam passages (the dark places).

These passages are slots less than 2mm wide, and up to 14mm deep.  The plans call for 6 of these deep, narrow, dark slots to be made in the cylinder blocks, upon which many many hours of work have already been lavished.   In addition, the slots have a 90 degree bend in the depths.  And that bend is only 2mm away from the cylinder.

The thought of a broken drill bit, or milling cutter, at those depths in the cylinder blocks, fills me with apprehension.

So I have done what I usually do when facing a difficult task with potentially disastrous consequences….  nothing.

I am waiting, thinking, and hoping that some thought bubble will pop, and give me the answer as to how to accomplish the task with some certainty of success.

Any suggestions would be welcome.

Maybe it is not achluophobia.  maybe it is atychiphobia.

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Cylinder valves for triple, and a neat method for cutting thin grooves.

The triple expansion steam engine now has a valve in each cylinder head.  They are manually controlled, not automatic, and I guess that is the reason they are called “false” valves.

The body of each valve was shaped in the CNC lathe, using software called “Ezilathe”.   There is a lot of good software for CNC milling machines, particularly Mach 3, but not much for lathes, at least for the non professional user.  “Ezilathe” is a free program (currently), works brilliantly, and was written by my friend Stuart.  It has an inbuilt simple CAD program, automatically generates G codes, and has a G code editor.   It also has a terrific, easy to use threading facility. It has an accurate simulator, and a tool editor.   Do a search on CNC Zone to download a copy.

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The “false valves” in the cylinder heads.

One problem which I experienced with these valves was that the thread which secures the valves to the heads, stopped short of the expanded hexagon part by about 1mm, and I needed to turn a very narrow groove in the stem to allow the hexagon to screw down hard on the head.  I do not have a lathe narrow grooving tool with enough reach to do this, so the following photo shows how it was done…

A broken slitting blade, held in a shop made holder.  Normally I use it under power, but in this case, the part was held fairly tenuously, so I turned the lathe spindle by hand.  It worked perfectly!

A broken slitting blade, held in a shop made holder. Normally I use it under power, but in this case, the part was held fairly tenuously, so I turned the lathe spindle by hand. It worked perfectly!

Just for interest. This tiny engine was made by model engineer Peter B on a 3D printer.  It is about the size of a matchbox.

Just for interest.
This tiny engine was made by model engineer Peter B on a 3D printer. It is about the size of a matchbox.

Piston rods for triple, and some engraving.

A good aspect of retirement is that the there is time for learning a new skill.  (Time, but not necessarily brain power.)

A case in point for me is the trials and errors of engraving.

In previous posts I outlined the steps in setting up the engraving spindle on my CNC mill, and the mechanical issues now seem to be fixed.

But getting lettering which is crisp, clear and attractive, in brass is a bit more complicated than, say, using a computer printer.

Issues:  Selection of cutter (angle of point, flat area or not),Spindle speed, feed rate, depth of cut, coolant or not, and selection of font are all variables to consider, and try out.  Also whether the letters are raised or excavated.

Each brass plate (65 x 32mm) takes 15-30 minutes to engrave, plus set up time.  So I have spent many hours in the last week trying various combinations and permutations.

Here are some pics of early results.

Finger for scale, and for privacy of the recipient. The quality is OK, but not quite as sharp as I would like.

Finger for scale, and for privacy of the recipient.
The quality is OK, but not quite as sharp as I would like.  Lettering is 0.75mm deep.  Perhaps a little too deep.

Label for a steam engine.  It is crowded and fussy, but I will probably use it until I get around to making a better one.

Label for a steam engine. It is crowded and fussy, but I will probably use it until I get around to making a better one.

Some progress on the triple expansion steam engine, but not much to show visually.  The pistons and piston rods have been made and fitted.   The piston rods screw into the pistons, and then have a lock nut on top.  The lock nut will be loctited at the final assembly.

I had an issue with the piston rods not being exactly concentric with the pistons, probably due to inaccuracy of my lathe chuck.  So I skimmed the piston surface while holding  the piston rod in the most accurate chuck in my workshop, which is the engraving spindle.  See the photo.

The pistons, piston rods and viton rings.

The pistons, piston rods and viton rings.

Turning pistons on a vertical mill. Not the clearest photo. It shows the high pressure piston (the smallest one) held in the collet chuck of the engraving head, being skimmed with a lathe tool which is held in the milling vise. It worked very well indeed!

Turning pistons on a vertical mill.
Not the clearest photo.
It shows the high pressure piston (the smallest one) held in the collet chuck of the engraving head, being skimmed with a lathe tool which is held in the milling vise.
It worked very well indeed!

Pistons for triple expansion steam engine.

Yesterday I turned the pistons for the steam engine.

The plans called for the pistons to be made in 2 halves, and the rings to be cast iron.

But the plans also showed the cylinders were cast iron, and my castings were all gunmetal.

So with gunmetal cylinders, I decided that iron rings were not appropriate.

I have used graphite impregnated packing for other steam engines, but after investigating the use of Viton O rings, I have decided to use them.

Viton rings are easy to install, cheap, easy to replace, and apparently work well.  They would not be used in an engine doing serious work, but my steam engines are more for display and interest and education, and will do few hours under steam.

Also Viton rings are quite small.  So if I decide later on that I want to change the Viton to packing or something else, I will simply turn larger grooves in the pistons to accept the alternative.

The pistons with Viton rings .

The pistons with Viton rings .

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