# 1/20th Scale Burrell



## glue-itcom

I'm designing, drawing and building a 1/20th scale Burrell traction engine and thought I would share some details here as well as on my pages 






These are the rear wheels, rims machined from mild steel, spokes from 0.9mm thick brass. the wheels are 97mm in diameter (machined from 4 inch round bar)


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## dnalot

I will be following your build. Looks like your off to a good start.

Mark T


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## glue-itcom

To put it into perspective, here is the image that I'm using as the fundamental starting point


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## glue-itcom

I finished the front wheels a couple of weeks ago (quite a few more hours available during lockdown)





Sat on the jig with an axle through the centre, it was all heated and soft soldered. The brass hubs took a few goes before I got them right, however, just makes it even better to get them right in the end.


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## NickP

Look forward to following along Nigel. HGood work


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## glue-itcom

The four wheels together having machined the hub faces in the lathe and hand-cranking it - was just too nervous to machine these once all constructed under power. Details of the build of the four wheels and the mistakes I made along the way are all on my gallery page.

I worked out there was a total of 64 parts and 60 rivets in the four wheels. The rear wheels are 97mm in diameter and the front wheels 70mm.


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## Peter Twissell

Nice work Nigel. Did you pick the scale so you could machine the largest parts (rear wheels) on a small lathe?
What is your plan for firing / heat source? I am guessing solid fuel will be a little fiddly at this scale.


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## glue-itcom

Peter Twissell said:


> Nice work Nigel. Did you pick the scale so you could machine the largest parts (rear wheels) on a small lathe?
> What is your plan for firing / heat source? I am guessing solid fuel will be a little fiddly at this scale.


Hi Pete, I got to 1/20th scale by accident, the size of the engine was determined by me wanting to be able to print the elevation of the engine on a sheet of A4 paper. I wanted an engine that would on the mantlepiece. Heat source is going to be methylated spirits, I've been making some simple calculations around this: steam and methylated spirit consumption. The boiler has 7 flue pipes, but will be a simple cylinder and so some heating underneath of the main boiler barrel. I have the basic design for the firebox, this is next on my list to do.


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## glue-itcom

This is the drawing I'm using, my red lines over the top from my estimation of boiler angle


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## Peter Twissell

So are you "freelancing" the design from that one drawing?
Reminds me of designing and building model aircraft based on simple 3 views from library books in my distant youth.


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## glue-itcom

Hi Pete, yes, this drawing, a lot of images of the real thing and some other views that people have sent me. 

From all of this I'm making good old fashioned plans, eg rear wheels:






OK, very simple plans that I can print, scribble on and use in the workshop.

The boiler is coming along, but will be a simplified boiler at this scale.


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## glue-itcom

the door for the Burrell with a simple hinge and latch (note that the door is 25mm wide)

I don't really need a functioning door as the intention is to run this on meths, but this looks cooler and I might want to steam it on coal just once to try it...


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## glue-itcom

A brief clip of me opening and closing the door, just to show it works:


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## glue-itcom

Do you all get to a certain point in a build and then divert to mending/upgrading a tool to allow you to make the next part?

Well, I've been absorbed by a cheap cnc engraver that I bought to engrave the smokebox door, it was just too cheap and so I've just spent time upgrading.....



I'm still not sure this will actually be good enough for the task, but I've learnt a lot. The belt length calculator is embedded now in the Excel workshop calculator.


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## glue-itcom

Having tried a low (hmm) cost CNC engraver and failed I went back to basics and tried ferric chloride, after a few goes I now have the steps sorted and getting some reasonable results






You need these bits:

Laser printer - or access to a photocopier
Inkjet glossy photo paper
Brass sheet
Ferric Chloride
Plastic Tub
The steps are quite easy, but added some tips I've been finding along the way on brass etching


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## Peter Twissell

Nice work Nigel!
I tried some FeCl etching on brass for a motorcycle project some years ago, with only limited success.
I didn't print the design, simply painted etch resist onto the part and scraped it away freehand. The etching worked fine, but was limited by my artistic ability.


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## glue-itcom

Must admit I had come across the laser printing idea before, but had never really tried it. Then I remembered I had some old inkjet photo paper hanging around and thought I would give it a try. This works really well, plus you can perfect your design first on the PC. Also, Ferric Chloride is reasonably ok to handle.

Gradually adding some more hints and further reading to the page, will develop it as a reference so please send me all of your own learnings.


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## glue-itcom

Had to create the front door again as the lettering was wrong and the etching was poor. 




The font was difficult to find, but my son pointed me at google font and then helped me with Inkscape.


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## shorrog

That looks excellent, how long did it take to etch and did you use the Frerric chloride?
Graham


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## glue-itcom

shorrog said:


> That looks excellent, how long did it take to etch and did you use the Frerric chloride?
> Graham



Hi Graham, yes, ferric chloride and etched for around 2 hours (used wires to hang it face down in the ferric chloride). Everybody says clean and must admit that this is key, have added some notes to my page on etching brass. Be prepared to create a few parts as it does take some goes to get everything sorted. Best regards, Nigel


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## Larry G.

Ferric chloride is a widely used and thoroughly understood  industrial process.   Very little needs to be re-invented.  
We used a ferric chloride spray etching system to produce deep- and through-etched clock parts in brass and tool steel.  Working on a small industrial scale we used Kodak KPR dip-coated resist and litho negatives of original artwork.   Thorough degreasing and oxidation removal are key.  Warming the solution accelerates the process. If we weren't spraying with PVC and titanium built equipment we would have added aeration.  
For limited production the references cited are very good, particularly VON Industrial and nontoxicprint.com.


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## awake

Ferric chloride works well, of course ... but there is a much-cheaper alternative that home-shop folks may be interested in. Two caveats: 1) this is much cheaper for me where I am - maybe not true elsewhere, and 2) I use this to etch printed circuit boards, i.e., copper - I believe it also works on brass, but I have not personally verified it.

The etching solution is made by mixing two parts drug-store hydrogen peroxide with one part hardware store muriatic acid (hydrochloric acid - often sold as brick etch, or in pool supplies). "Do as you oughtta, mix acid with watta" - always put the water (or in this case, hydrogen peroxide) in first, then slowly pour in the acid. The etchant can be used once and then disposed of (safely - do NOT pour it down the drain!! I mix with concrete to "solidify" the dissolved copper and then dispose of as per county regulations), or you can go on to to create cupric chloride by dissolving in more copper. This solution can be reused over and over again simply by re-oxygenating it (bubbling air through it). Again, a caveat - I have read many reports of this process, but I confess that, given the limited frequency and quantity I need, I find it easier just to mix up a fresh batch each time.

One other word of warning - don't store your muriatic acid inside your workshop; the fumes will make everything rust! I store it in a covered plastic container outside my garage - seems to have worked just fine for many years now, and I am still nowhere near to using up the first container of acid that I bought.


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## glue-itcom

I've been designing and machining the front axle, then today finished the hub caps







This next image gives you the scale as my hand can nearly wrap around the axle and smokebox. 

The front wheels are 70mm in diameter


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## glue-itcom

Have struggled getting the 1/20th scale door hinge correct, lots of parts in the bin. Finally I have something that I think looks ok.




In essence I went back to basics and broke the problem down. Then looked again at the assembly. Plus I bought and tried some silver solder paste - not cheap at ~£16 for 10g, but wow. Maybe it is cheap as you only need tiny amounts, well on this size of parts tiny amounts.


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## glue-itcom

I used two countersunk 10BA bolts to fix the plate to the front door. I should probably add 2 more, but space is very tight. 




I'm pleased with the look of the hinges now, just need to add the towing eye to the front and add the steering links onto the axle for this front part to be approaching a good level of completion. OK, still lots more to do even then.


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## glue-itcom

Since the last post I've been working on the hornplates. I've called them hornplates+ as I've incorporated the main tub in the same parts. At 1/20th scale I just thought this would make it easier to make and control accuracy.





I then rolled and edged a panel to fit between the two plates.




I riveted this in a few places and then soldered it as I found I needed to lock the location.

The soldering though worked rather well as I used a "hot air gun" - a great technique for soldering largish brass constructions.





I have a lot of riveting, manipulating and fettling to do to get this correct and how I want this to look in the end. 

The hot air gun soldering I will be using again, it works much better than an open flame torch for soft solder as it doesn't generate the surface oxides.


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## glue-itcom

I'm looking at the water tank and thinking of a vertical water pump with a vertical plunger that I can easily access at the rear of the tender.

I need to find some designs for water pumps unless there is a commercial part that would fit the bill - please do share links, designs, thoughts on this as I'm feeling a tad out of my depth.....


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## Peter Twissell

Hi Nigel,
The second steam engine I built was a Stuart Beam Engine. I made a freelance water pump from scrap material, using balls and springs from a Triumph motorcycle oil pump for the valves. The pump ram is a section of 1/8" bright steel bar, with an O ring seal. It is only the connection to the beam which prevents the ram from coming out of the cylinder. After a little use, I had to replace the steel balls with stainless, as the originals had corroded. 35 years on, it still works, which is quite amazing, as I had just guessed everything and made it up as I went along.
I'm sure it is well within your capacity to design your own pump.


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## glue-itcom

Peter Twissell said:


> Hi Nigel,
> The second steam engine I built was a Stuart Beam Engine. I made a freelance water pump from scrap material, using balls and springs from a Triumph motorcycle oil pump for the valves. The pump ram is a section of 1/8" bright steel bar, with an O ring seal. It is only the connection to the beam which prevents the ram from coming out of the cylinder. After a little use, I had to replace the steel balls with stainless, as the originals had corroded. 35 years on, it still works, which is quite amazing, as I had just guessed everything and made it up as I went along.
> I'm sure it is well within your capacity to design your own pump.



Hi Pete,
All of the model pumps I find online are the fairly standard horizontal piston with a vertical handle and link to the piston, However, this page from 1920-30.com has a great image of a simple vertical pump. I think I'm going to draw something up on these lines and see how well it works. Also, not that dissimilar to the pump you describe for the beam engine.
Cheers, Nigel


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## Peter Twissell

Looks just the job, scaled to an appropriate size for your engine.
It's worth noting that the ram doesn't need to be a 'piston fit' in the bore, it's just acting as a displacer. Provided the seal is good, it will work.


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## werowance

This tractor looks wonderful.  are you making your rivits?  i ask because if you are id kind of like to see more of that process if you have time.  i have watched several methods using copper wire but still not satisfied that i can do it by what i have read and watched so far.   but wonderful job


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## glue-itcom

werowance said:


> This tractor looks wonderful.  are you making your rivits?  i ask because if you are id kind of like to see more of that process if you have time.  i have watched several methods using copper wire but still not satisfied that i can do it by what i have read and watched so far.   but wonderful job



Thanks for the kind words. The rivets are from EKP Supplies. Must admit that I'm not finding them easy to get consistent , but I think this is due to the fact that I'm hitting them with a different number of blows depending on where they are. They are rather large for this engine, but the smallest I could buy and I wasn't up for making them. I have made a bracket that I lock in the vice with a harden silver steel rivet punch in the end, this supports the other side of the rivet. However, this job really needs 2 pairs of hands as I still end up balancing the tender on the rivet anvil side. I will get some photos of this and post them.


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## glue-itcom

They are brass rivets and I did a trial with them as they come versus heat annealed. They worked better for me as they come. But I'm ending up using a bought rivet punch at first and then swapping to a homemade silver steel punch to get a better rounded head


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## glue-itcom

This is a 1/4 inch mild steel plate with a 4mm blind hole drilled in the end to accept a silver steel punch. 

The bracket allows me to support the other side of the rivet inside a structure - Solid Rivets page on my blog is a collection of info on my learning to date.

The punch is not fixed in the bracket just in case it needs changing. The punch is hardened silver steel and has a domed concave feature to fully support the head of the rivet. I rounded the outer edge as well to minimise any damage.






Also, I sandwich the mild steel bracket with a sheet of aluminium in the vice as this then adds some compliance and so more easily maintains the clamp load. This is really important when extending the reach of the bracket.


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## werowance

Nice,  thank you for showing and explaining.  that helps me.  again very nice work.


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## Peter Twissell

I made a slightly more ambitious tool for riveting. Essentially, it's a lump of steel plate with a long slot in it and a couple of tubes welded to the end, either side of the slot.
One tube supports the dolly, as in Nigel's tool, the other acts as a guide for the punch, keeping it aligned to the dolly.
I use an air hammer to get consistent results.


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## glue-itcom

I definitely need to try an air hammer. 150 brass rivets turned up from EKP Supplies today, bought 3/8" long so I can cut them to the correct size.

I spent Saturday afternoon adding 2mm half-round beading to the top edge - used an old tin of Fry's Fluxite (I think nearly 40 years old) - still working fine.





I've also been making the rear axle bearings from PB, have been turning using high angle tungsten bits designed for aluminium - will share more on this.


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## glue-itcom

The engine is now up on all 4 wheels, I like putting the parts together as it allows me to think about the design and next steps.





The rear axle bearings were made from phosphor bronze. I machined this using the tungsten bits designed for aluminium, it machined so well.


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## werowance

it looks great.  i did not know you could buy half round brass stock.  the way you have bent, persuaded it into place and soldered looks way better than anything you could buy factory made or store bought.


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## MIKE4444

Ex   construction , well done , MIKE


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## ACHiPo

Wow that looks great!


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## glue-itcom

I just couldn't find a flywheel that was even roughly the right size, so had to make one from solid cast iron. 

At first it was a tad thick on the rim







so, back in the chuck...at only 9mm thick I needed some spacers. Don't know about you, but I find it difficult to get all 3 in at once. My solution was to use a sticky wax to hold the spacers.






In the end I got a thinner edge flywheel, round spokes and was really happy with the blending





72mm OD and 9mm wide


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## glue-itcom

A bit of video showing the anvil I made to support the other end of the rivet


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## Steamchick

Beautiful work! Better than a casting in appearance. You have gone the extra mile with the blending and large radii, so it looks "Cast". Well done!
K2


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## Steamchick

Hi Glue-it. All you need do now is dip it (cold) into hot wax (melted candles) to give it an extra 1/16in. overall, than make a plaster mold and cast an aluminium, or zinc/mazac, or resin, pattern that you can keep for making "cast-copies" when you need them in future! Flywheels (being "precision located mass") don't need to be Cast Iron or Brass, but just a dense material - like Mazac (from scrap castings from car scrap-yards) does a good job at a lower melting point when making castings. - Looks like steel (grey) when finish machined. After making a pattern, the wax on your nice machined part can easily be broken of and cleaned with spirit before painting.
K2


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## glue-itcom

Steamchick said:


> Hi Glue-it. All you need do now is dip it (cold) into hot wax (melted candles) to give it an extra 1/16in. overall, than make a plaster mold and cast an aluminium, or zinc/mazac, or resin, pattern that you can keep for making "cast-copies" when you need them in future! Flywheels (being "precision located mass") don't need to be Cast Iron or Brass, but just a dense material - like Mazac (from scrap castings from car scrap-yards) does a good job at a lower melting point when making castings. - Looks like steel (grey) when finish machined. After making a pattern, the wax on your nice machined part can easily be broken of and cleaned with spirit before painting.
> K2


Hi K2, that's a nice idea, I like the method. I will have a go. Best regards, Nigel


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## glue-itcom

The crankshaft for the Burrell in my design is rather tight to the top of the firebox. I might just raise the bearing blocks slightly to make this work.





I will make up the crankshaft and then I can have a play. Against the original drawings it is looking quite close, as someone pointed out though the drawings are for the compound version. I'm building a single cylinder engine.






Being a single cylinder version I will get a bit more room to play with.


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## glue-itcom

This image shows the detail. This is not a perfect build and wish my skills were that bit more finessed, but hopefully this looks the part.

I added multiple towing locations after talking to my brother. He worked on a farm for many years and his opinion was that this would be a real benefit for towing offset trailers and for maneuvering trailers in yards.


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## glue-itcom

The boiler for the Burrell is just a set of parts. However, before finalising this design I thought I should make a boiler and see how easy or difficult it is to do. So using the same outer copper tube I designed a simple vertical boiler. This boiler is very small.




The centre tube has 6x small 5/32 inch cross tubes and it was silver soldered in 2 stages using easyflo 24 and then using easyflo 55.

The hydraulic pressure testing was done with a simple garden plastic sprayer with a modified outlet nozzle.






I pumped the boiler up to just over 2x working pressure (my design is for 50psi) and then locked it off. The pressure dropped by 10psi over an hour, appears that I have a slight weeping around the pressure gauge joint. I will seal this better today and run this test again before running a steam test at 1.5x working pressure.


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## glue-itcom

Someone (not sure who now) asked me how this 1/20th scale Burrell compares to a Mamod. Some pictures comparing it to the Mamod steam wagon





















Makes me realise how much work I still have left to do.


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## Peter Twissell

Your Burrell compares to a Mamod in the same way that a Brough Superior compares to a Chinese moped.


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## glue-itcom

Peter Twissell said:


> Your Burrell compares to a Mamod in the same way that a Brough Superior compares to a Chinese moped.


Thanks Pete, at the moment though it is just an outline. I'm sidetracked by the vertical boiler at the moment as I have to understand the boiler thoroughly to enable me to get to the next level of design.

The boiler surface area to volume is quite high and so heat loss is going to be an issue and I will need to get a good fire going. Plus I need to find a routing for the water gauge - at the moment this doesn't appear trivial.

Thanks, Nigel


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## glue-itcom

I'm probably going to end up running the traction engine on methylated spirits, but Would like to try and fire it with coal. Therefore, I've made two different bases for the vertical boiler. Really just learning about firing, airflow etc. 

This also meant I needed to make a grate. As this is only 42mm in diameter I decided to machine it from solid cast iron.






I made an aluminium jig so that I could grip the edges gently in the mill vice and so that I could flip it over and machine the underside.


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## glue-itcom

This small boiler is driving me a bit mad, I'm struggling to get the heat into it. It gets to temperature and pressure, but it takes ages considering the meths burner I'm using.

So I decided to instrument the boiler with thermocouples and to then do some measurements. Using silver thermal compound that you use on PC cpu's to connect them to a heatsink to attach the thermocouples.






I'm using a Pico Technology measurement board and software, very easy to use. I will share the data and my analysis.


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## glue-itcom

I measured the cooling curve for the boiler with and without cladding, surprisingly not that different. 






I will calculate the area that is clad versus unclad as I think this will shed some light on how effective this cladding is.

From my simple calculation it appears that the boiler is losing around 40W of heat at 140°C and 40psi (this is my design operating point).


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## bobden72

glue-itcom said:


> Someone (not sure who now) asked me how this 1/20th scale Burrell compares to a Mamod. Some pictures comparing it to the Mamod steam wagon
> 
> View attachment 123985
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> 
> View attachment 123986
> 
> 
> View attachment 123987
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> View attachment 123988
> 
> 
> Makes me realise how much work I still have left to do.


I hope you have just put the rear wheels on for the photo as they are the wrong way round.  The strakes should lead on the inside of the wheel.


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## glue-itcom

bobden72 said:


> I hope you have just put the rear wheels on for the photo as they are the wrong way round.  The strakes should lead on the inside of the wheel.


yes, just propped on. Thanks for being the nerd who noticed.


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## glue-itcom

I've now created a very simple model of the boiler based on a lumped copper and water assumption.




Using the cooling curve I've estimated the heat loss to be ~35W at the operating pressure and temperature and my first design of meths burner and firebox produces 54W of heat input.


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## glue-itcom

I've now measured and processed the data looking at the heat output of the burner as I change the burner to boiler distance

Using the instrumented boiler I heated it up for each test distance from around 50°C water temperature to >120°C. Thus giving me enough data to estimate the heat input power. I also measured a new cooling curve for this firebox and boiler setup so that I got an accurate heat loss estimate versus temperature.

Once I had processed the data I could then plot the burner heat input to the boiler versus distance.






This plot shows that the peak in heat output is when the burner is around 85mm from the base of the boiler. Also, it shows that this firebox and burner is producing nearly double the amount of heat that the original design generated.


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## glue-itcom

This is my first attempt at making an electrical heating system for the boiler. 






The mathematical model shows that after applying the layers of insulation on top of the heating wires the heat input was between 17W and 18W. 






The power supply shows 20.2W of electrical output, but we lose 0.3V in the cables and connectors. So input to heating wire around the boiler is 19.7W

This gives me a system now where I can do some more experiments to understand the insulation of the boiler.


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## glue-itcom

This boiler has now finally been rebuilt with better cladding and a new firebox. This time the firebox has been made from sheet mild steel.


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## glue-itcom

After some time away from the Burrell I have finally got back to making parts. This is my roughed out steering wheel




Not perfect, but at 22mm diameter it should clean up well.


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## glue-itcom

I've now turned it around, carefully machined the back. I even used my simple mild steel tool to form the rim, then I filed and tumbled it




You get to see the size of this now.


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## glue-itcom

I've now added a fast handle / knob to the wheel. This was made from 2mm diameter brass round stock.






A complete steering wheel for the Burrell, another part designed and made.


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## Steamchick

Will you train a squirrel to drive it? Or other mammal with small enough hands?
Beautiful modelling!
K2


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## glue-itcom

I spent yesterday afternoon machining the arc on the underside of the cylinder saddle. This is a phosphor bronze part that will get silver soldered to the boiler and then the cylinder will be bolted to it. I thought though I would share how I got the arc radius correct using a flycutter


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## glue-itcom

The saddle is now taking a form. Next I have to add the bolts around the edge, these might be just for show as I don't want that many holes into the boiler.


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## glue-itcom

An overview of the engine build to date:


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## Peter Twissell

You mention in the video making an injector to deliver water to the boiler.
Are you proposing a real injector at this scale, or a piston pump?
I'll be very impressed if you can get an injector to work!


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## glue-itcom

Peter Twissell said:


> You mention in the video making an injector to deliver water to the boiler.
> Are you proposing a real injector at this scale, or a piston pump?
> I'll be very impressed if you can get an injector to work!


Hi Pete, sorry, just a piston pump. I think a proper injector would be very difficult without lots of cfd and then lots of testing. Cheers, Nigel


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## Steamchick

I bought a proprietary injector for a stationary boiler I use at up to 45psi. It has high superheat. But the model injector only works somewhere above 60psi... or so I found out later. They are good and reliable on 5in. Locomotives, but the smallest commercial injectors can be temperamental, a bit like some drivers....
K2


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## glue-itcom

The cylinder saddle is going to be silver soldered to the boiler. The bolt fixings are just for looks and so I needed to grind the countersunk heads completely flush.

I made an abrasive drum from a bolt and a piece of hardwood. Machined the correct diameter including wet and dry paper thickness.






Impact adhesive works great. Plus it stays in place when using lots of cutting oil on the wet and dry.

I set the saddle up in the mill and then protected the table.






The final part finish looks rather good.


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## Steamchick

Good to see different techniques - and that they work! Hope the silver soldering to the boiler goes well. A tip? Try using a pencil to mark off the area beyond the joint where you don't want the silver solder to take. Just "shade" the area, but make sure no pencil where you do want the solder. Also using a paste of flux and water pre-applied ensures it fills the gap to clean the surfaces and encourage the capilliary action when silver solder is applied. (But I reckon you know all that anyway.).
K2


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## glue-itcom

Steamchick said:


> Good to see different techniques - and that they work! Hope the silver soldering to the boiler goes well. A tip? Try using a pencil to mark off the area beyond the joint where you don't want the silver solder to take. Just "shade" the area, but make sure no pencil where you do want the solder. Also using a paste of flux and water pre-applied ensures it fills the gap to clean the surfaces and encourage the capilliary action when silver solder is applied. (But I reckon you know all that anyway.).
> K2


Thanks for the tip on using a pencil mark, I've never seen that before. I'm used to mixing the flux with water, works very well. 
Best regards, Nigel


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## Steamchick

Hope the pencil mark helps? I forget to bother... so have widespread silver solder coating everywhere.
K2.


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## glue-itcom

Steamchick said:


> Hope the pencil mark helps? I forget to bother... so have widespread silver solder coating everywhere.
> K2.



I was going to have a practice with the pencil masking first to get a feel for it.


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## Steamchick

Good thinking Boss!


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## glue-itcom

The steering worm and wheel has been great fun to make as a pair, even though they are tiny:



The resultant pair fit together so well.


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## glue-itcom

The steering bottom end is now coming together.


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## glue-itcom

I made a simple brass post and bearing to support the top end of the steering column and added a hub to thread the steering wheel onto.






I then just had to assemble the engine once again. I keep having to do this to get inspiration for the next part and to check clashes etc.






The flywheel is only balanced there, still need to make the crankshaft. However, already I can see how tight everything is.

The worm and wheel are so smooth when you turn the steering wheel, brings a smile.


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## glue-itcom

A very brief video showing the steering wheel and worm gear operating


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## glue-itcom

30 degree C in the workshop, but with the door and all of the windows wide open I spent some time turning the crosshead guide and then slot drilled the open sides.







At first I was worried about the size of this crosshead, but I offered the unit up to the traction engine and it looks ok. This traction engine is going to be stand-off scale as I have used quite some licence to achieve 1/20th scale.


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## glue-itcom

Crosshead in context with the engine - I think the guide looks ok:






Let me know your thoughts   

Here's a closeup of it


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## Peter Twissell

Looks to be nicely in proportion with the rest of the engine.
Good work!


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## GrahamJTaylor49

Hi Nigel,
Looking very nice, well proportioned and still shiny. Many years ago I turned my hand to a 2" Burrell compound showman's engine. Had me in tears at times but in the end I managed to finish it. It sat in my living room gathering dust and cobwebs until in the end I sold it and bought a new Triumph 900ST. The local gun shop, who was a client of mine, got me into long rand pistol shooting so I ended up making my own long rang pistol. More toys. Shooting pistols at up to 1000 yards on Stickeldown Range at Bisley. Not bad for a pistol. Sat on a sand bag, bolt action, 12" barrel from Doug Shillen, 2oz trigger, Burris 10x scope and wildcat 460 Wetherby necked down to 30 cal. 0.1" group at 200 mtrs. Great fun until our bloody government banned the hand guns. Enough of this twaddle, I am now building a Stuart Turner Major beam engine and having great fun doing it. Will attach a few photo's as it comes along. Anyway, I am now going to go out for a ride on the current motorbike, A Yamaha Niken. Funny looking thing with 2 front wheels, goes well though.
In the mean time everyone enjoy our hobby and stay safe.
Graham T. South coast of the UK.


----------



## glue-itcom

Now onto the crankshaft. If you remember my earlier design discussions I was struggling to see a way to getting a 6mm throw and hence 12mm stroke. Well, there are a few things that help this: 1. offset of the cylinder and curvature of the firebox 2. ability to lift the bearing blocks slightly 3. two-piece crankshaft and hence single piece conrod big-end.

So here is a sketch of the crankshaft:






I assembled and silver soldered this with a single piece main shaft. That made it easy to align everything and machine surfaces. One of the last actions was to then split this main shaft and machine back to the internal web faces.






Just to prove it still splits into two and that I didn't make a mess of the silver soldering:






A little bit of cleaning and then a polish and this will be ready. And change the bolt to something more subtle!


----------



## glue-itcom

and it clears...






The crankshaft clearance is looking good all round.


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## Peter Twissell

Looking good, Nigel!
Next challenge will be clearance for the eccentric straps.


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## glue-itcom

Peter Twissell said:


> Looking good, Nigel!
> Next challenge will be clearance for the eccentric straps.


Hi Pete, Yes, I think they will be a challenge. I'm not going to split them, I think I will use grooves pin/bolt running in the groove to align. Thanks, Nigel


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## glue-itcom

The phosphor bronze saddle that I made is being bolted to the boiler before I silver solder it in place.






I made the bolts from PB, avoiding brass parts being permanently fitted to wet areas in the boiler based on possible dezincification.


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## glue-itcom

The valve chest is made from two parts:






Making the bearings out of one part meant that it was all aligned. I then removed the centre section.






The valve chest is just 22 x 20 x 7mm.

I'm thinking of making an external nut from PB to make the gland for the push rod - is that ok?


----------



## glue-itcom

The Burrell steam valve is causing me some issues. My original thought was to build it into the side of the saddle. However, that feels difficult within the space available. I think I have 3 options and thought it would be good to share these and the design to date:


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## Peter Twissell

Hi Nigel,
My own preference would be towards creating the valve within the saddle, perhaps even using some parts of the standard valve.
Not the easiest option, but I am one for spending several hours on a single detail.
Other opinions may vary.
Pete.


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## glue-itcom

Peter Twissell said:


> Hi Nigel,
> My own preference would be towards creating the valve within the saddle, perhaps even using some parts of the standard valve.
> Not the easiest option, but I am one for spending several hours on a single detail.
> Other opinions may vary.
> Pete.


Hi Pete, I do keep coming back to that approach. I may have to see if I can find some very small valve designs. Thanks, Nigel


----------



## glue-itcom

Sometimes I look at what I'm making and go back and look at some of the models my dad made in the 1980's. The comparison below with the clock and the valve chest plaque was just because I'm struggling to get the detail into the etching.






He etched, painted the numerals, cleaned the top surface and then silvered the dial. This clock is ~39mm high (bottom of feet to top of handle) and it works (it uses a wristwatch movement that he pulled apart and constructed on the back of the face).


----------



## glue-itcom

The original image I created had a jagged edge, this is an issue with powerpoint when you shrink the size right down. The best package for creating graphics that scale and keep their form is Inkscape, an upside is it's free, the downside is it takes time to learn how to use. The first one wasn't bad, but the ferric chloride was cold and I didn't leave it long enough. However, this gives you the scale of the part. The capital letters are 1.4mm high.






I warmed the ferric chloride up, I find the easiest way is to place the bottle into a bowl of hot water. 

I then etched four more plaques and I think I now have a Charles Burrell nameplate.


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## glue-itcom

Looking in more detail at the steam valve design. The schematic looks reasonably simple. However, I've been looking at a number of references to try and improve my background knowledge of steam valve design.





My conclusions are very simple:

Smooth the steam flow path.
Can the valve reliably shut steam flow off completely?
Does the valve provide enough control?
Does the valve work at all pressures?
Are all parts resistant to corrosion?
Control rod must seal and still freely operate.


----------



## glue-itcom

In preparation for silver soldering the phosphor bronze saddle to the boiler I've been running some coupon tests.

Effectively looking at applying silver solder in different locations on the bolted sandwich of copper and phosphor bronze.






Interestingly the silver solder happily tracks (capillary action) through the joint, including through the threaded section.






The right hand side configuration appears to have given the most complete joint. I then sectioned the joints:






You can see that on the LHS the thread of the bolt has voids where silver solder has not tracked completely through all interfaces.

Left and right hand side parts are consistent through the images, although I have had to mirror some of the images to make this consistent (this doesn't affect the results). 

The plan is to run some more tests, will post these as well if just to show consistency.


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## smittman

Hi Nigel, love your build so far. Are you going to put a sight glass on the rear of your boiler if so you could come off of it with your valve and then on to the valve box. You could still use the one coming up into your valve box straight up to the safety valve and save some precious heat loss by only running steam one way from your valve. Just a thought your build has helped lots on my build of the myfordboy traction engine. Especially  making the saddle fit my boiler with a fly cutter. It saved me lots of trial and error. Thanks Dave (Smittman)


----------



## glue-itcom

smittman said:


> Hi Nigel, love your build so far. Are you going to put a sight glass on the rear of your boiler if so you could come off of it with your valve and then on to the valve box. You could still use the one coming up into your valve box straight up to the safety valve and save some precious heat loss by only running steam one way from your valve. Just a thought your build has helped lots on my build of the myfordboy traction engine. Especially  making the saddle fit my boiler with a fly cutter. It saved me lots of trial and error. Thanks Dave (Smittman)


Hi Dave, 
The sight glass is not easy as the firebox is separate and so I don't have water on the rear face (the boiler extends into the firebox up to the hole in the top). 






I might have to fit it into the rear panel and then pipe to the boiler, but this needs some design.

My intention is to line the firebox with a ceramic to direct the heat through the boiler and reduce losses. 

Pleased this is helping with the MyfordBoy engine. Cheers, Nigel


----------



## glue-itcom

Some parts make you smile and fixing the Burrell nameplate to the valve chest is one of those.





I used an easy flo ready mixed silver solder paste and as you can see it worked really well.


----------



## glue-itcom

Steamchick said:


> Good to see different techniques - and that they work! Hope the silver soldering to the boiler goes well. A tip? Try using a pencil to mark off the area beyond the joint where you don't want the silver solder to take. Just "shade" the area, but make sure no pencil where you do want the solder. Also using a paste of flux and water pre-applied ensures it fills the gap to clean the surfaces and encourage the capilliary action when silver solder is applied. (But I reckon you know all that anyway.).
> K2


Finally I've done some testing to see how well a graphite pencil works as a masking tape for silver solder.









This works quite well.


----------



## glue-itcom

The position of the steam valve and machining it into the saddle has caused me some pain. However, I finally decided that it wouldn't fit into the saddle. 



Although painful, this has allowed me to move forward and now silver solder the saddle to the boiler shell.

An image of saddle silver soldered to the boiler.








My test coupons and checking out different silver solder masking techniques paid off.

The engine reassembled and I think it's looking good.






The silver solder coming out from the edge is minimal and yet it is complete all the way round. This will be covered by an insulation sheet and a brass sheet wrap anyway.


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## Steamchick

Hi nigel,
having done a few boilers, I strongly recomend that the insulation is built from the following: 

Wrap the hot boiler outer with aluminium foil, shiny side out: This reduces the radiated heat by half-ish, or more.
Cover the aluminium in your preferred insulation fabric: I have successfully used corrugated cardboard, paper (especially if it is embossed o it forms trapped cells filled with air) , wool (knitted fabric), proprietary "flame resistant" insulation sheet, but don't try bubble wrap or anything that will melt or char at the boiler temperature.
Cover insulation with a sheet of paper (I use "used" printer paper).
Cover the paper with aluminium foil: shiny-side inwards. 
Then fit your metal cleading as per normal.
The 2 layers of aluminium foil cause 95% of the radiated heat to be trapped - and, as this can exceed the conducted heat through the insulation, it  can reduce your "wasted-heat" to less than half of what it would be without the invention of reflecting surfaces by *Sir James Dewar* . That's a lot of heat made into useful steam!
On my boilers, the main insulation means the outside temperature is below 40degrees C. whereas the boiler surface is above 140degrees C.
And do the same around the firebox if you can?
On tubing carrying steam - e.g. water gauge, (except for the pressure gauge siphon tube) you can also insulate with cotton string wound carefully around the pipework and over the fittings, then painted with domestic matt white emulsion piant - which makes it look like the original asbestos lagging - but is much safer. But your traction engine won't have much exposed steam pipework.
Cheers!
K2


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## Steamchick

Here's what Wiki says: "In 1860, the French scientist Jean Claude Eugene Peclet[2] experimented with the insulating effect of high and low emissive metals facing air spaces.[3] Peclet experimented with a wide variety of metals ranging from tin to cast iron, and came to the conclusion that neither the color nor the visual reflectance were significant determining factors in the materials’ performance. Peclet calculated the reduction in BTUs for high and low emissive surfaces facing into various air spaces, discovering the benefits of a radiant barrier in reducing the transfer of heat. "

On Sir James Dewar: "About 1892, the idea occurred to him of using vacuum-jacketed vessels for the storage of liquid gases – the Dewar flask (otherwise known as a Thermos or vacuum flask) – the invention for which he became most famous. The vacuum flask was so efficient at keeping heat out, it was found possible to preserve the liquids for comparatively long periods, making an examination of their optical properties possible. Dewar did not profit from the widespread adoption of his vacuum flask – he lost a court case against Thermos concerning the patent for his invention. While Dewar was recognised as the inventor, because he did not patent his invention, there was no way to prevent Thermos from using his design.[6] ".

You live and learn...

You can also use "space blanket" material instead of aluminium foil (Baking foil).
K2


----------



## Steamchick

glue-itcom said:


> Finally I've done some testing to see how well a graphite pencil works as a masking tape for silver solder.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> This works quite well.


Good! Glad to see this knowledge is being passed around.
A centuries old trick... a blacksmith taught me 50 years ago...
K2


----------



## glue-itcom

Steamchick said:


> Hi nigel,
> having done a few boilers, I strongly recomend that the insulation is built from the following:
> 
> Wrap the hot boiler outer with aluminium foil, shiny side out: This reduces the radiated heat by half-ish, or more.
> Cover the aluminium in your preferred insulation fabric: I have successfully used corrugated cardboard, paper (especially if it is embossed o it forms trapped cells filled with air) , wool (knitted fabric), proprietary "flame resistant" insulation sheet, but don't try bubble wrap or anything that will melt or char at the boiler temperature.
> Cover insulation with a sheet of paper (I use "used" printer paper).
> Cover the paper with aluminium foil: shiny-side inwards.
> Then fit your metal cleading as per normal.
> The 2 layers of aluminium foil cause 95% of the radiated heat to be trapped - and, as this can exceed the conducted heat through the insulation, it  can reduce your "wasted-heat" to less than half of what it would be without the invention of reflecting surfaces by *Sir James Dewar* . That's a lot of heat made into useful steam!
> On my boilers, the main insulation means the outside temperature is below 40degrees C. whereas the boiler surface is above 140degrees C.
> And do the same around the firebox if you can?
> On tubing carrying steam - e.g. water gauge, (except for the pressure gauge siphon tube) you can also insulate with cotton string wound carefully around the pipework and over the fittings, then painted with domestic matt white emulsion piant - which makes it look like the original asbestos lagging - but is much safer. But your traction engine won't have much exposed steam pipework.
> Cheers!
> K2


Hi K2, the only issue is I need to wrap the boiler in a total thickness of less than 1.5mm including the outer brass sheet. I might have to experiment with some thermocoupled blocks to get some comparative insulation numbers. I will set something up and then see if people have different options to test. That sounds like fun actually.

For the firebox my plan is to line this with ceramic, I was going to see if I can machine one of the white ceramic blocks for soldering. I will have a go at this soon to see how it goes. I still need to design how the pipes come out the back of the firebox for the pressure gauge, water gauge, steam valve etc.

Thanks, Nigel


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## Steamchick

As the cooking foil is only a thou or so thick it does a lot of insulation for almost no real thickness. The thinnest foil used to be on the inside of cigarette packets - glued onto tissue paper and could be separated - carefully. But you can't get that anymore as they vacuum deposit aluminium onto plastic nowadays - e.g. for crisp packets, etc. - And who has cigarettes anyway?
K2


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## Steamchick

On the subject of insulation thicknesses, you can buy proprietary stuff in various calibrated thicknesses, but an old pair of wool suit trousers will give you fabric that needs a few layers to make a mm of thickness. Pure cotton and linen also come in very thin fabrics. Regular print paper can be a tenth of a millimeter. Even nose or toilet tissue is very thin - and has lots of air space and minimal fibres to conduct the heat! 
All you really want is air-space for insulation, with enough "fibre" to trap the air from moving (Convection currents - even sub-millimetre - can be very effective at transmitting heat). All these allow you to precisely build-up the required thickness so you have good insulation inside the cleading.
But don't leave out the aluminium foil!
Enjoy!
K2


----------



## Steamchick

Hi again Nigel,
Aha! - having seen the Mamod alongside your engine, I can see why you want to line the firebox with insulation. (I guess you are in the UK?) I have had success with insulating and sealing fireboxes by using Exhaust Assembly paste - from the local car accessory shop - instead of firebrick cement. It sticks better to steel (unpainted, grease-free), and after firing becomes rock hard - and can be quite strong if thick enough, and applied in thin layers and allowed to dry/cure before firing.... Otherwise it cracks (drying shrinkage). But fire-brick cement is harder to achieve a robust lining (and it doesn't stick so well to the steel!). Spread it thinly (maybe 1mm thick?) using a pallet knife or some-such... then let that dry overnight before applying a second layer. After a couple of days for final drying, warm gently - with the meths flame in the boiler should be OK..? and as it gets hot enough it will cure, as there is a refractory element in it, so chemical changes occur and make it rock-hard. You can strengthen it (as with exhaust-pipe repairs) by having layers of aluminium foil between the layers of cement. "butter" the foil with a layer of cement, then apply this as a poultice/bandage to the steel ... allowing a week in a warm, dry place to dry out (The foil traps the inhibitor moisture).
The only problem is that shrinkage during hot curing causes tension stresses in the cured cement, so on the inside of a curved sheet it can pull-away from the steel. But if you follow the "Roman" cementing construction method, you'll do it in strips, with gaps, grouting the gaps after curing the strips... I'm sure you can work it out and save the problem of machining the very fragile ceramic board...
K2


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## Steamchick

On another point. I like the experimental way you tackled the meths burner in vertical boiler problem... measurement of heat power, etc. 
I did some crude calculations on the heat flow of meths in a Mamod boiler versus using a ceramic gas radiant burner. 
A couple of points that may help you?

 The meths burner was more effective on the horizontal Mamod boiler, because the hot flames/exhaust gas wrapped around the boiler shell. The ceramic only "shone2 radiant heat on the underside, and less than half the radiated heat hit that part of the boiler anyway. But side reflectors increased the heat transmission to the boiler shell to make the ceramic "equally" effective - and more convenient - than the meths burner: BUT you have a flue tube in your boiler!
On a vertical boiler, I compared the ceramic radiant burner versus a gas "camping-stove" burner - with same jet, gas and power. The Radiant ceramic "lost" some radiant heat by shining all the way through the flue tubes, but the overall power transmission from combustion  to steam was about the same: One was more efficient at heating the bottom face of the boiler, but then had less heat to transfer to the walls of the multiple flue tubes, the other had hotter gas entering the flue tubes, but the exhaust temp was almost the same - ergo the heat transfer was equivalent with the 2 different burners.
On an horizontal boiler, with gas burner beneath the long boiler shell, I found I could use 1 jet larger on a ceramic burner, as the majority of the heat was radiated onto the boiler shell, leaving cooler exhaust gas (lower volume and higher mass) to pass through the flue tubes than with the limitations of the flues on the flame gas burner.
Noting that Meths needs a LOT of air... and you will be restricted by your flue size and the draught "up the lum", you may find a ceramic burner can give you more "power" from the fuel because you can maximise the air with the gas to get a proper fast combustion of the gas (Light blue cones surrounded by darker blue cones) - providing you don't over-fuel the air intake capabilities of the ceramic burner. The different mix of CO2 and H2O in the gas exhaust, compared to the meths exhaust, may give you better performance? But I reckon you will need a very well insulated firebox in either case to get the hot gas into the flue tube to heat the water to steam. It probably needs a thermodynamics chemist to explain the "better" fuel, but I'm sure with your experimenting approach you'll find the better solution for you.
Cheers!
K2


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## Steamchick

Hi Nigel, More musings... 
Just in case you have not checked the design of the vertical boiler - and the Burrell boiler - for the flue tube in compression....(The boiler pressure compresses flue tubes):  I have a spreadsheet that I use to do some quick calculations, based on ASME (USA) Copper boiler design and testing regulations.
My "quick" check:- 

for a 10mm OD, 8.6mm bore copper tube in compression in a boiler, with cross tubes, the ASME max pressure would be between 30psi (OK) and 35psi (NG)  NWP...
for a 22mm OD, 20.2mm bore copper tube in compression in a boiler, with cross tubes, the ASME max pressure would be between 20psi (OK) and 25psi (NG) NWP...
The main reasons for this:

Copper in compression is only 20~25% of the strength of copper in tension, 
Cross-tubes are "wall penetrations" - so ASME uses a standard "stress concentration factor" of 3.3 - which de-rates the NWP horribly, 
ASME ( as British standards, etc.) use the Factor of Safety as >8 for the design of copper pressure vessels.
ASME de-rates copper (as naturally happens!) above "room temperature", so the "permissable stress" reduces dramatically with "steam" temperatures. (Halved at 100psi compared to room temp).
So (for example) a copper tube "OK" for internal pressure  room temp water at 6 bar (FOS = 8) is de-rated:

to NWP ~3.5 bar at 50psi NWP steam:
Then to NWP ~11.4psi if used as a flue tube,
Then to NWP =  3.5psi if there are "penetrations" - such as cross-tubes.
Horrible?

So please send me your tube sizes and boiler details if you want me to advise on SAFE sizes of material?
Regards,
K2


----------



## glue-itcom

Steamchick said:


> Hi Nigel, More musings...
> Just in case you have not checked the design of the vertical boiler - and the Burrell boiler - for the flue tube in compression....(The boiler pressure compresses flue tubes):  I have a spreadsheet that I use to do some quick calculations, based on ASME (USA) Copper boiler design and testing regulations.
> My "quick" check:-
> 
> for a 10mm OD, 8.6mm bore copper tube in compression in a boiler, with cross tubes, the ASME max pressure would be between 30psi (OK) and 35psi (NG)  NWP...
> for a 22mm OD, 20.2mm bore copper tube in compression in a boiler, with cross tubes, the ASME max pressure would be between 20psi (OK) and 25psi (NG) NWP...
> The main reasons for this:
> 
> Copper in compression is only 20~25% of the strength of copper in tension,
> Cross-tubes are "wall penetrations" - so ASME uses a standard "stress concentration factor" of 3.3 - which de-rates the NWP horribly,
> ASME ( as British standards, etc.) use the Factor of Safety as >8 for the design of copper pressure vessels.
> ASME de-rates copper (as naturally happens!) above "room temperature", so the "permissable stress" reduces dramatically with "steam" temperatures. (Halved at 100psi compared to room temp).
> So (for example) a copper tube "OK" for internal pressure  room temp water at 6 bar (FOS = 8) is de-rated:
> 
> to NWP ~3.5 bar at 50psi NWP steam:
> Then to NWP ~11.4psi if used as a flue tube,
> Then to NWP =  3.5psi if there are "penetrations" - such as cross-tubes.
> Horrible?
> 
> So please send me your tube sizes and boiler details if you want me to advise on SAFE sizes of material?
> Regards,
> K2


Hi K2, 

Thanks for the comments on meths versus gas etc. I think I need to find a gas burner for this engine to make my life a bit easier. Some calculations and someone else looking at the boiler size would be much appreciated.

The horizontal Burrell boiler sizes:

Shell: 44.45mm OD, 1.6mm wall
Flue tubes: 7 off 4.79mm OD 0.7mm wall
End plates: 1.1mm thick
I can easily change the end plates and flue.

The vertical boiler was just me experimenting and I must admit that it has been consigned to the do not use this again pile. The simple model was interesting though and as you say, meths needs a lot of air.

Best regards, Nigel


----------



## Steamchick

Hi Nigel,
I'll see what I can prepare today... I'll send a file direct to you if that is OK?
My "bibles":

Safety of Copper Boilers - Kozo  Hiraoka - from Live steam and Outdoor railroading: Issue Nov 2006. (Back copies can be bought from the magazine).
Model Boilers and boilermaking: by K.N.Harris. - A lot of what he does is correct mathematically, but limits need to be checked versus the ASME stuff by Kozo-san, as Mr Harris was "speaking from and earlier era", without some of the real technical considerations by ASME.
The fundamentals I have found also consider some University technical papers, and "odd bits of advice" from professional engineers who have worked with ASME and other codes, so know what to apply.
The bottom line is that the factors of safety of *, combined with "maximum permissible stress" de-rated by copper at elevated temperature, compression factors, Stress concentration factors, etc. mean that we should be using much thicker copper than Mr Harris postulates.
I don't know the latest UK Regs. - and they seem to be very elusive - so that's why I refer to ASME. ("Half the planet" does anyway).
K2


----------



## Steamchick

I can also do some calculations for the ceramic versus meths... Crude but not "unreal", and (as I make ceramic burners for E&@y) can also make one or guide you to make your own to suit the model.
What size is the internal section of the firebox that will take a burner?
Regards,
K2


----------



## glue-itcom

Steamchick said:


> I can also do some calculations for the ceramic versus meths... Crude but not "unreal", and (as I make ceramic burners for E&@y) can also make one or guide you to make your own to suit the model.
> What size is the internal section of the firebox that will take a burner?
> Regards,
> K2


Brilliant and thanks. The internal section is 47mm wide and 38mm long, thanks, Nigel


----------



## glue-itcom

I machined the double eccentric as one part, thus allowing me to fix it with one grub screw






Thought the setup might be of interest as well


----------



## glue-itcom

After a lot of help from Steamchick I've managed to make and silver solder the boiler end plate stiffeners in place. 






I think I'm a gluten for punishment pursuing the silver soldering in a kiln. The Easy Flo 24 did not flow as well as some of the lower temperature silver solders.


----------



## Steamchick

Hi Nigel. I have not tried oven brazing or silver soldering. But in industry, it was common practice for soldering steel tube assemblies, as these could be assembled to jigs, with the self-fluxed paste spelter, then passed through a conveyor oven tunnel for heating to well controlled temperatures, and cooling...  A very reliable, controllable, production process. Hope you have more success next time!
Did you pickle clean parts or abrasive clean them before applying paste? Possibly that is a cause of your issues? Or perhaps you didn't hold at top temperature for long enough?
Ken


----------



## glue-itcom

Steamchick said:


> Hi Nigel. I have not tried oven brazing or silver soldering. But in industry, it was common practice for soldering steel tube assemblies, as these could be assembled to jigs, with the self-fluxed paste spelter, then passed through a conveyor oven tunnel for heating to well controlled temperatures, and cooling...  A very reliable, controllable, production process. Hope you have more success next time!
> Did you pickle clean parts or abrasive clean them before applying paste? Possibly that is a cause of your issues? Or perhaps you didn't hold at top temperature for long enough?
> Ken


Hi Ken,
When it works it goes very well. I did an abrasive clean and then a pickle, but the pickle is getting old. I need to refresh. 
I think there might be a few things worth looking at: flux, size of silver solder and oven temperature. 

The test piece worked very well and I just abrasively cleaned it.






The oven takes time to recover the temperature on the real parts as it is small. I could go hotter initially. Also, during the recovery the flux might get degraded.

I could hammer the silver solder into thinner and smaller parts. This would allow the heat transfer to be better.






The resultant joint is well covered with silver solder, just some parts that haven't fully flowed. So, I'm ok with it. 

I keep going back to using the kiln for silver soldering as the results can be fabulous. However, must admit that silver solder paste and a blowtorch gives brilliant results.
Cheers, Nigel


----------



## Steamchick

Also a thick pencil line can form a limit to where the solder flows... it won't cross the line of clay and graphite. I use a Carpenter's pencil as a good black line for this... (when necessary).
K2


----------



## glue-itcom

Steamchick said:


> Also a thick pencil line can form a limit to where the solder flows... it won't cross the line of clay and graphite. I use a Carpenter's pencil as a good black line for this... (when necessary).
> K2



Hi Ken, yes, I tried this on a few samples, it's not quite masking tape for silver solder, but it works well










Nige


----------



## glue-itcom

The flat smokebox door was annoying me so much, so I made a radius turning tool and then machined a domed door with a radius of 71.4mm






I think this curved smokebox door looks better


----------



## glue-itcom

I created a new hinge from brass tube, using a jig to align it whilst machining and silver soldering. The brass plaques were then bolted in place with 10BA cs bolts. Now I have a smokebox door for the Burrell that I think looks better.



I need to machine the beam that goes behind and the fixing bolt


----------



## glue-itcom

I've now made the Burrell door handles and the locking system, this now all works at 1/20th scale.







This hopefully shows the basic locking system.

The Burrell door lock is a T-head bolt with flat sides on the threaded section. This bolt goes through the door from the back, a handle with a slot then goes on allowing the bolt to be rotated. A second handle with a threaded not then allows the bolt to be pulled up tight.

In the smokebox a beam goes across the diameter of the opening and has a slot in it to allow the bolt head to go through. Then the bolt is rotated and hence the T-head gets a purchase on the beam.







The handles were made as one part based on them being so small and then I split them into two parts later.







Still lots to do


----------



## glue-itcom

I’ve been thinking about the Burrell gearing for some time. Calculating the overall ratio, estimating the maximum torque and speed of the traction engine.

I think 1000rpm is a good top speed for this small double acting engine. The rear wheels are 97mm OD and the gearing gives me around 10:1

My simple calculation says that this will give me 1.1mph or ~0.5m/s which feels reasonable for an engine that might run on my dining table.

This is very similar speed to a Mamod Wagon with 2000rpm, 16:1 and 75mm OD wheels


----------



## glue-itcom

12mm bore at 60psi is ~45N on the conrod

14mm stroke means ~0.32Nm of torque at the flywheel

hence 3.2Nm at the wheel

the drive wheels are 97mm OD and so hence 32N of tractive effort and the engine will be around 1.8 to 2kg

Also, I'm likely to run at a pressure of 45psi mostly and so I think around ~24N

That should be fine


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## glue-itcom

Also, just been working out how to get to 10:1 as an overall ratio and where the layshaft can go.






then some calculations of the options (using excel)






and I think I have a sensible result


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## Peter Twissell

I do like a spreadsheet for such calculations - each of my build folders has several, most of which I will probably never look at again.


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## glue-itcom

Peter Twissell said:


> I do like a spreadsheet for such calculations - each of my build folders has several, most of which I will probably never look at again.


agree, so much easier just to lay the calculation out and check the alternatives


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## glue-itcom

the first prototype differential for the Burrell, some way to go yet, but hopefully you can see what I'm trying to achieve


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## glue-itcom

I have to firstly say a huge thanks to JG for sorting out the angles and cutting of these bevels. He did say bevels are not easy to get right and I'm definitely learning that the heard way....

I spent a happy hour (no drinking) setting out a 9.5° angle on the milling table and then aligning the rotary table to it.















Now I have to go and cut those gears. Must admit that the cost and effort required in fitting the DRO has been paid back several times over...and it isn't the simplest thing to fit


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## glue-itcom

The differential has taken some time to get to even operate. However, after making some shims to space the crown wheels correctly I have something that operates as a differential. 



I did run this at speed on the lathe to get it run-in - this helped a lot.

I might still re-make this, but for now I know I can get something that works as a differential. In practice it will not actually see that much work and so it is probably ok.


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## glue-itcom

a bit longer video showing the assembly of this miniature differential


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## petertha

Beautiful work. The videos really do justice to the intricate parts assembly of the mechanism.


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## glue-itcom

petertha said:


> Beautiful work. The videos really do justice to the intricate parts assembly of the mechanism.


thank you


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## glue-itcom

I've had a bit of a break from building this, however, in the last few days I've sorted the rear axle and the rear hub caps. Now I think it is taking shape. On my latest status page of the Burrell Traction Engine there are even more images.


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## glue-itcom

I have to say that the indexing feature that I machined into the table support for my Unimat 3 Pillar drill is so useful for items such as these hub caps.


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## glue-itcom

Back to the Burrell at last and this time the conrod.

As this engine is rather small, hopefully the matchstick puts it into context, I decided to split the crankshaft. This allowed me to make the big end of the conrod from PB.











The other parts were made from brass and then all silver soldered together like jewellery.






I really like the easy flo silver solder paste for small parts such as this. Just remember to heat the parts with the blow torch away from the joints before then heating the joint/silver solder.


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## johnmcc69

That's going to be an incredible model!

 Very WELL done!

 John


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## glue-itcom

johnmcc69 said:


> That's going to be an incredible model!
> 
> Very WELL done!
> 
> John


Hi John, thanks for the feedback. Still a long way to go and still concerned about getting it to run on steam at this scale. Thanks, Nigel


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## glue-itcom

Spent a few hours making the eccentric pushrods and then testing them on a drill:







They need a bit more fettling and finishing, but I'm happy for now.


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## glue-itcom

Just been making the main drive gear in PB, it's quite small at 27 teeth and 0.5mod



The driveline is described in the following image, hope this makes sense






more details on the blog: Burrell Crankshaft and Layshaft Gears - glue-it.com


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