# Miniature Traction Engine



## Nigel Taylor (12 Jan 2021)

Thought I would share with you all the long term project that is on my workbench at the moment.

This is a 1/20th scale working Burrell traction engine. The 1/20th scale was an accident as I took an drawing from the Burrell works and scaled it in elevation to fit on a page of A4.

The smokebox and axle is starting to come together 







The rear wheels have also been designed, machined and assembled:





These are just 97mm in diameter.

This is an image of the parts laying on the A4 drawing





The final image shows the number of parts I haven't made yet rather than the number complete......


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## toolsntat (12 Jan 2021)

Lovely, true craftsmanship and all respect to you for doing it.
Do you look in on Traction Talk?
Cheers Andy





Traction-Talk


This is the Traction-Talk discussion forum



tractiontalkforum.com


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## powertools (12 Jan 2021)

I hope that you will keep updating this as I would like to follow your progress.


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## paulrbarnard (12 Jan 2021)

That looks fantastic. My Dad builds live steam trains so i appreciate the amount of work that goes in to these things. Definitely post more progress.


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## Nigel Taylor (12 Jan 2021)

toolsntat said:


> Lovely, true craftsmanship and all respect to you for doing it.
> Do you look in on Traction Talk?
> Cheers Andy
> 
> ...


Hi Andy, yes, a good forum. Thanks, Nigel


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## AES (12 Jan 2021)

Lovely job. A man after my own heart (and before he died, my dad was a traction engine man too. But in his case it was primarily a Fowler Showman's engine). But for me, the primary "trigger" is/used to be "it's got to fly"!

Good luck though, you've got lots of fascinating work ahead, and please keep us posted - especially pix please.


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## Nigel Taylor (16 Jan 2021)

Had to go back to basics on the door hinge for the smokebox, broke the design down further and looked again at the assembly. Plus I tried some silver solder paste from CooksonGold, not cheap but wow.


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## Nigel Taylor (17 Jan 2021)

Been improving the brass etching by cleaning the plate with acetone before applying the resist and etching.


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## bourbon (17 Jan 2021)

That brass etching is impressive


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## Orraloon (18 Jan 2021)

Way way above my metal working level but great to watch.
Regards
John


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## Nigel Taylor (22 Jan 2021)

I have now machined the brass chimney top, silver soldered it in place and then re-machined. 




I think you can only just see the silver solder line....


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## Nigel Taylor (25 Jan 2021)

*Tip:* Blue permanent marker works as a great alternative to engineers blue and it's cleaner.

This is my marking out of the hornplates for the Burrell in 1/16th inch thick brass





This is them then cutout, filed to the lines and then the pair of plates split apart (they were held together with double sided tape)






These were then bolted to the firebox. I just had to prop all of the parts together and get a photo.....





this and many more projects are on my gallery page


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## Nigel Taylor (8 Feb 2021)

I spent Saturday afternoon adding the beading to the edge of the tender. It's not perfect as half-round brass beading tends to rotate as you try and bend it flat around corners. I should have made some jigs.






I also used some very old flux, it worked perfectly considering just how old it is....




I posted the image from the tin of fluxite as it just makes me smile.


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## AES (8 Feb 2021)

Beading looks good mate. A +1 for Fluxite, no matter how old, but if not teaching granny, DO make sure you flush under running water with an old toothbrush to get rid of ALL residue.

P.S. my tin is so corroded you can't see "the little devil" any more!


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## paulrbarnard (8 Feb 2021)

Things like fluxes tend to be a little less effective than they used to, or at least they seem to be to me. I assume the nasty ingredients that made them so effective are no longer permitted. It's the same for electronics solder. Modern lead free just doesn't seem to work as well. I acknowledge it could simply be the rose tinted spectacles of age or the lingering effects of lead poisoning.


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## AES (8 Feb 2021)

No, I think you're right Paul. Not so sure about electronics work (I only use cored solder for the little I do in that area and it still works OK), but definitely is so for metal working "soldering", both hard n soft. Less "acid" in them I guess. Fortunately I have a good stock of old-fashioned tinman's lead solder (+ a gurt big iron) and just use Fluxite for soft soldering.


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## Nigel Taylor (10 Feb 2021)

I've been machining Phosphor Bronze (for the rear axle bearings) using the carbide bits designed for machining aluminium - wow, no use of cutting fluid and the results are superb.


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## Nigel Taylor (10 Feb 2021)

Once I had made the bearings I just had to assemble the parts I have made to date






The engine was designed to fit on a sheet of A4 in elevation and here it is sat on top of an A4 notebook.


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## gregmcateer (10 Feb 2021)

This is just beyond stunning.
Lovely to see the Frys label - reminded me that my best mates dad used to be senior chemist there many years ago.
Thanks for sharing your incredible work.
Greg


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## Nigel Taylor (11 Feb 2021)

gregmcateer said:


> This is just beyond stunning.
> Lovely to see the Frys label - reminded me that my best mates dad used to be senior chemist there many years ago.
> Thanks for sharing your incredible work.
> Greg


Hi Greg, 
Thanks for the comments. As a maker you always see the issues with it. I'm a self-taught engineer over many years, but still make things in a way that probably makes the pro's wince. I get there in the end by making parts a few times.
The Fry's label on the front of the tin is so good, it great and would make a great T-shirt.
Best regards,
Nigel


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## Nigel Taylor (18 Feb 2021)

I made a flywheel for the Burrell from solid cast iron, but it looked too heavy






so, back to the lathe and some more machining and then some milling. Finally some hand belt sanding to get to this






I created a narrated video to show the simple steps to machining this from solid


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## Peri (18 Feb 2021)

Weirdly, I made a fly-wheel today for my 'free-time' project at work !


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## Nigel Taylor (19 Feb 2021)

Peri said:


> Weirdly, I made a fly-wheel today for my 'free-time' project at work !
> 
> View attachment 103880


cool engine design


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## AES (19 Feb 2021)

Peri said:


> Weirdly, I made a fly-wheel today for my 'free-time' project at work !
> 
> View attachment 103880



That's an interesting engine Peri. Is it steam/compressed air powered?


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## Peri (19 Feb 2021)

Rather than muscle in on Nigels thread, I've posted my build up here


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## Nigel Taylor (24 Feb 2021)

just some bling photos of it all together, well, the parts so far.




The crankshaft is the next part to be made, a tad tight though to the top of the firebox





and then finally sat on the A4 notebook


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## Nigel Taylor (27 Feb 2021)

When I bought the silver solder paste I thought it was expensive, but as I've got to use it I've realised just how good it is. Plus you use such a small amount that just 10g goes a long way, it's actually rather a good price.






This has allowed me to build the bearing block up as a sandwich






This is just after heating them up to temperature with a simple handheld butane torch. You see a small amount of liquid silver and it just flows. After this I machined them to the final size I needed.


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## Nigel Taylor (2 Mar 2021)

This is definitely not a towbar that you're going to use to pull the caravan!!! But a towbar for a very small traction engine.






The multiple pin locations are to help with towing offset trailers and maneuvering trailers in a tight spot.


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## donwatson (2 Mar 2021)

Forgive my intrusion but I have been following this thread and have just read the "towbar for a very small traction engine." piece. You mention the use of permanent marker as a substitute for 'Engineers Blue', I don't think it is. Engineers Blue is a violent blue type ointment, slightly sticky, that we used to use when scraping bearings to fit and when 'frosting' slides on mating ground surfaces. It was a nightmare in use and seemed to get everywhere. On the other hand 'Engineers Marking Blue' was in a spray can and was sprayed on the surface to be scribed. It dried very quickly. We used it on the marking off of large valves where the casting was machined from scratch and had to be marked for machining to be started (setting up datums).
Just thought I would say.
take care and stay safe
Don W
PS I had noticed the comment earlier in this article as well but never connected in my wonky brain.


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## Nigel Taylor (2 Mar 2021)

donwatson said:


> Forgive my intrusion but I have been following this thread and have just read the "towbar for a very small traction engine." piece. You mention the use of permanent marker as a substitute for 'Engineers Blue', I don't think it is. Engineers Blue is a violent blue type ointment, slightly sticky, that we used to use when scraping bearings to fit and when 'frosting' slides on mating ground surfaces. It was a nightmare in use and seemed to get everywhere. On the other hand 'Engineers Marking Blue' was in a spray can and was sprayed on the surface to be scribed. It dried very quickly. We used it on the marking off of large valves where the casting was machined from scratch and had to be marked for machining to be started (setting up datums).
> Just thought I would say.
> take care and stay safe
> Don W
> PS I had noticed the comment earlier in this article as well but never connected in my wonky brain.


Hi Don, yes, sorry. For blue marking I still find a permanent blue marker very easy to use and it works great as a background for marking parts. I have to say I have a tin of the blue paste and it does go eveywhere. I remember years ago having a bottle of blue that you painted on and it dried quickly. The benefit of the pen is it only goes exactly where you want it. However, it is not as robust as the proper blue.
Thanks for pointing this out, Nigel


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## donwatson (3 Mar 2021)

No problem. lol  It was just something that niggled at my brain.


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## Nigel Taylor (22 Mar 2021)

Before making the boiler I thought I should have a go at just making a standalone boiler - in fact my first boiler.






This tiny boiler is not that simple to assemble, even at 650°C for the lower temperature silver solder it's quite difficult to get the heat in with a smallish butane torch.


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## gregmcateer (22 Mar 2021)

I'm just blown away by this.


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## Nigel Taylor (26 Mar 2021)

I was lighting the methylated spirit burner on the boiler and it was blowing backwards, so I took a slow-motion video of it:



I still have my eyebrows - Note: don't try this at home.


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## dickm (26 Mar 2021)

Have a feeling that my Fluxite tin actually had the price printed on the tin, in shillings and pence, as a permanent part of the label. Inflation must have been low then!


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## J-G (26 Mar 2021)

Not only Inflation - Resale Price Maintenance was in play


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## Nigel Taylor (28 Mar 2021)

Making a cast iron grate from a solid piece of cast iron was quite easy using a simple aluminium jig






It's only 42mm in diameter. I used an aluminium jig so that I could clamp it in the mill vice without damaging it.


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## paulrbarnard (28 Mar 2021)

Nigel Taylor said:


> Making a cast iron grate from a solid piece of cast iron was quite easy using a simple aluminium jig
> 
> 
> 
> ...


Very clever! I’ve got to remember that trick.


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## Nigel Taylor (28 Mar 2021)

paulrbarnard said:


> Very clever! I’ve got to remember that trick.



I might be able to help as I've slowly been creating a page listing different workholding techniques, I need this as my brain is like a sieve and I will just re-invent the wheel every time otherwise.


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## paulrbarnard (28 Mar 2021)

Nigel Taylor said:


> I might be able to help as I've slowly been creating a page listing different workholding techniques, I need this as my brain is like a sieve and I will just re-invent the wheel every time otherwise.


That is very useful. Interestingly I seem to have the identical clamp set in the red wall mount . 
I just rebuild my milling vice. It came with the mill and had 3mm, yes millimetres not thou, of vertical slack in the moving jaw with no adjustment possible. I machined 60 degree tapers on the slides and made gibs for it. It now clamps perfectly.


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## Nigel Taylor (28 Mar 2021)

paulrbarnard said:


> That is very useful. Interestingly I seem to have the identical clamp set in the red wall mount .
> I just rebuild my milling vice. It came with the mill and had 3mm, yes millimetres not thou, of vertical slack in the moving jaw with no adjustment possible. I machined 60 degree tapers on the slides and made gibs for it. It now clamps perfectly.


Drop me a line if you have any additions, I will add them on


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## Fergie 307 (28 Mar 2021)

Nigel Taylor said:


> Before making the boiler I thought I should have a go at just making a standalone boiler - in fact my first boiler.
> 
> 
> 
> ...


Nice job. I use one of the little oxy sets for small brazing stuff. Got fed up with the outrageous amounts BOC want for their cylinders for something I only use once in a while. I use a map torch to get some temperature into it and then the oxy set to just lift it to the final temperature, saves on the oxy bottles by letting the map do most of the work.


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## Chris4658 (1 Apr 2021)

Wow! Lovely craftsmanship there! Really nice work


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## Nigel Taylor (1 Apr 2021)

I made the little vertical boiler to test myself, but I've got carried away. It is now clad and I've made the siphon tube for the pressure gauge.





I silver soldered the the 1/16th inch diameter copper pipe with easyflo paste. I made the banjo bolt from brass.

I will update with a movie once it is in steam, hopefully this weekend...


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## Nigel Taylor (6 Apr 2021)

This little boiler has turned back into the test piece it was meant to be. I've been using it to run tests with a methylated spirit burner and got poor results.

So I instrumented the boiler with thermocouples and a Pico Tech logger.






I ended up using 3 thermocouples to record air temperature, water temp and steam temp above the water. As well as I could measure these as I just made a blind hole in the boiler plugs and pushed the thermocouples inside.






I now have quite a lot of data.






I need to have a look at this and see what conclusions I can get to with regards to the boiler design.


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## Nigel Taylor (6 Apr 2021)

Comparing the cooling curve for the boiler clad and unclad shows there is not actually that big a difference.






Now, these tests were run on different days and I need to go back and repeat some tests to understand what my real errors are. 

However, this might make sense as the boiler still radiates heat from a large surface area under and through the centre of the boiler. Plus there are a number of fittings that radiate.


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## Fitzroy (6 Apr 2021)

Vessel cooling is one of those things that will scale poorly when miniaturising a boiler. The rate of cooling of a vessel to the environment is proportional to the surface area to volume ratio. As you shrink a cylinder this ratio increases dramatically, a 5cm diameter vessel has a ratio 20 times greater than a 1m diameter vessel so it will cool 20times faster.


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## Nigel Taylor (6 Apr 2021)

Fitzroy said:


> Vessel cooling is one of those things that will scale poorly when miniaturising a boiler. The rate of cooling of a vessel to the environment is proportional to the surface area to volume ratio. As you shrink a cylinder this ratio increases dramatically, a 5cm diameter vessel has a ratio 20 times greater than a 1m diameter vessel so it will cool 20times faster.



Agree, the boiler size is similar in size to a Mamod and hence my desire is to improve on that design.


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## Nigel Taylor (6 Apr 2021)

Here is an image of the traction engine alongside a Mamod Steam Wagon, the vertical boiler is a test before building this boiler.


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## mcgranag (6 Apr 2021)

Great work, following with interest.


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## Nigel Taylor (9 Apr 2021)

I've now run a few experiments on the small vertical boiler to understand the optimum distance between the spirit burner and the boiler. 






Normal practice is that the hottest point is at the tip of the inner blue flame, however, there is a depth to the boiler surfaces as shown by this cross-sectional diagram.






So, using the simple assumptions, a new firebox and some more measurements on the instrumented boiler I get the following curve:






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.

I checked this calculation by looking at the boiler temperature versus time data. The original firebox and burner took just under 8 minutes to take the water from 60°C to 100°C. The new firebox and burner took just over 2 mins 30s for this same temperature change. You have to consider heat losses and heat input, but this makes sense.

PS if anybody wants to use any of the images I've post that is fine, just please add a link to my pages at glue-it.com thanks, Nigel


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## Nigel Taylor (12 Apr 2021)

I've built and tested an electrical heating system for the boiler, the intention being to calibrate the mathematical model and gain insight into the thermal insulation. The electrical input was 20.2W and the model estimated the electrical input between 17W and 18W over the period that the boiler was heated from 20°C to 120°C. I'm quite pleased with these initial results. This also gives me the tools to develop the insulation of the boiler.

Note: this system is only operating at 10.7V 

This image shows the nichrome wire wrap before I wrapped isolation and insulation over the top.






This has also shown me that I could electrically heat the boiler and I have another idea to improve on this deign.


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## Adam W. (20 Apr 2021)

Wow!


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## Echo-Star (20 Apr 2021)

Truly a master off your craft Nigel, and what a statement It makes of the skills you possess. The time you must put in to achieve a standard of work off this calibre is awe-inspiring. I am in awe.

Rob


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## Nigel Taylor (21 Apr 2021)

Echo-Star said:


> Truly a master off your craft Nigel, and what a statement It makes of the skills you possess. The time you must put in to achieve a standard of work off this calibre is awe-inspiring. I am in awe.
> 
> Rob


Rob, very kind words, but I have been making models for more than 40 years and 10 of those years were as an apprentice to my dad who was exceptional at this. Also, I do make a lot of mistakes, I do post these on my blog and on instagram to show that I'm very much human. I would encourage people to try something and to just take their time (another benefit of growing older ). Thanks, Nigel


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## Nigel Taylor (24 Apr 2021)

I bought a piece of hex mild steel, but it turned up and I thought it was a shame to turn it into a pile of swarf. So, after a long walk and some thinking time I decided to fabricate the final firebox design from sheet steel:






I think I have a simple way of making some louvres for the air flow


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## Nigel Taylor (12 May 2021)

I finally sorted the issue of getting heat into the small vertical boiler. I used a steam raising blower, then I tested 2 methods back to back and described them both in this video. Along with data that shows this simple technique increases the heat into the boiler from 50W to 350W


Steam raising blowers work rather well, now I just need to be able to finely control the heat input between 50W and 350W.....


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## Adam W. (13 May 2021)

I'm really impressed by your attention to detail Nigel.

This has to be the best project thread on this forum, it's nicely presented and I like that you don't shy away from sharing your research with us.


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## Nigel Taylor (13 May 2021)

Adam W. said:


> I'm really impressed by your attention to detail Nigel.
> 
> This has to be the best project thread on this forum, it's nicely presented and I like that you don't shy away from sharing your research with us.


Hi Adam, thanks, very kind. I really enjoy the science and engineering aspect and post things that I hope will help others. Best regards, Nigel


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## Nigel Taylor (13 May 2021)

Just realised that this thread shows a step change in the boiler that I should describe. That is the change from the mid colour oak cladding to the dark bog oak cladding. I removed the original oak cladding as I needed to understand the thermal behaviour of the boiler. This meant that I then had to put the cladding back onto the boiler, this gave me a chance to optimise it.

There are now 6 layers:

Teflon sheet – a thin baking sheet wrap
Medium weight paper wrap
Polythene – this was a thick clear polythene bag
Medium weight paper wrap
Air gap – created using thin wood veneer strips
Bog oak outer layer
The air gap is very small, this image shows me adding the external cladding and underneath you can see the very thin strips of veneer.




I then measured the performance of the final boiler cladding and compared it to the limit cases (ie no cladding and thermal blankets) and to the case where just the cylinder is insulated to a maximum condition (this represents the ultimate thermal cladding).




These performance curves are calculated from the cooling curve, mass and heat capacity of the boiler/water. The cooling curve is a fundamental parameter for any system and is easy to measure and so establish the heat loss to the environment.


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## Nigel Taylor (13 May 2021)

The black paint needs a mention. I needed a paint that could work at a high temperature for the chimney and the firebox. 

I found this coal black paint, initially I thought this description was really describing the colour. However, this paint is designed for painting your fake coal on the gas fire....really.







I had a quick search and saw that this paint is also used for stoves, so thought I would give it a go on the chimney and firebox. I've now fired the boiler a few times and this black finish is growing on me.

So, if you need a high temperature black paint then this paint from Rapide Products is rather good and cost me just £3.99 at a small hardware store.


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## Nigel Taylor (16 Jun 2021)

After making the test boiler, fitting a DRO, adding a stiffening plate and sandbag damping to the milling machine....I'm back working on the Burrell traction engine. Today I roughed out a steering wheel whilst waiting for cylinder material.





Not quite perfect, but considering it is 22mm across I'm ok, I might make another one....but for now.

I then parted it off and machined the other side. A little bit of filing, emery cloth and tumbling this afternoon.






I need to add a handle so you can turn it fast


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## Nigel Taylor (19 Jun 2021)

The handle is now in place, it doesn't rotate, but that might be asking a lot for a 1/20th scale Burrell steering wheel


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## donwatson (19 Jun 2021)

Love it


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## Nigel Taylor (21 Jun 2021)

The cylinder is being broken down into a design that I can make and seal. A design that I can make work at this small scale.





The fundamental feature of this design is a saddle that will get silver soldered to the boiler. Here it is shown part machined.


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## Nigel Taylor (25 Jun 2021)

An overview of the miniature traction engine build to date:


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## Nigel Taylor (11 Jul 2021)

The steering system is a worm drive of a drum that then winds the chains in and out. These chains connect to the front axle beam.

The first challenge was making a 6mm diameter 2mm pitch worm and wheel


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## pe2dave (11 Jul 2021)

A man with patience!


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## Nigel Taylor (11 Jul 2021)

pe2dave said:


> A man with patience!


I think my patience has improved with age. Also, I'm now happy to make the same part more than once as it is a great learning experience.


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## Nigel Taylor (15 Jul 2021)

I built up the bottom end of the steering system. The phosphor bronze bearing has a recessed section that the brass tag was rolled into and a flattened side with step that aligns on the edge. This angled edge was machined at 38.5° to align with the steering column. 





I think I'm getting more confident when working with sheet metal.





The worm sits snugly into the gear wheel. There is no chance that this can jump a tooth.

The bearing at the top end is a simple brass post. The steering wheel hub was machined from brass with an 8BA thread to accept the steering wheel. The steering column works very smoothly, just need to add the chains and attach them to the front axle.






I had to reassemble the parts, I need to make the crankshaft as the flywheel is balanced on a much thinner rod at the moment, hence slightly too low.


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## pe2dave (15 Jul 2021)

How can lumps of metal seem pretty. But (to me) it is.
Please post a video of it running when complete.


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## Nigel Taylor (15 Jul 2021)

pe2dave said:


> How can lumps of metal seem pretty. But (to me) it is.
> Please post a video of it running when complete.


Thanks Dave, just lots of patience to sometimes make 3 or 4 parts before you get it right. Might be sometime before it's running, but will post progress. Best regards, Nigel


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## Nigel Taylor (17 Jul 2021)

A very brief clip of the steering wheel and gear being turned


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## Nigel Taylor (21 Jul 2021)

Not sure if everyone else is struggling in the heat in the workshop, it's definitely slowed me down.

However, I did managed to turn and mill the crosshead guide.






The inside surface of this is the bearing for the mid-point joint in the conrod. Thus allowing the sliding seal to work on cylinder and hence enable the double-acting operation of the cylinder.


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## Nigel Taylor (27 Jul 2021)

The crankshaft has been made so that it splits into two parts. The conrod big-end then doesn't need to split. Thus I can reduce the thickness of the design as it doesn't need to have a bolt through it. Overall I can increase the crank throw and hence stroke. 

I managed to squeeze the throw out to 7mm and still clear the firebox. 






Thus the engine is 12mm bore and 14mm stroke double acting.


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## Nigel Taylor (2 Aug 2021)

I've bolted the cylinder saddle to the boiler using two square head phosphor bronze bolts that I made:






One has a hole through as this is the pathway for steam from the boiler. This will be controlled by a valve that I will fix into the side of the upright that divides the cylinder and valve chest.


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## Nigel Taylor (17 Aug 2021)

I made the valve chest from solid brass and then added the pushrod guides as one piece initially






Once this was silver soldered in place I then milled out the centre section, leaving me an aligned pair of bearings.






Now I have a roughed out valve chest, need to now make holes for fixings and the shaft gland nut.


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## paulrbarnard (17 Aug 2021)

Nigel Taylor said:


> I made the valve chest from solid brass and then added the pushrod guides as one piece initially
> 
> 
> 
> ...


That was cunning. I will try to remember that for the future alignment of bearing rods.


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## Nigel Taylor (18 Aug 2021)

paulrbarnard said:


> That was cunning. I will try to remember that for the future alignment of bearing rods.


The only issue might be that it was stressed whilst being silver soldered and when I removed the centre part it might have moved. Hopefully not... I will report on how well this has worked.


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## Nigel Taylor (30 Aug 2021)

The engine itself is coming along, now I need to look at the options for the steam valve:


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## Nigel Taylor (30 Aug 2021)

The valve is actually rather large compared to the cylinder and crosshead guide. This is the smallest valve I've found to date:


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## hog&amp;bodge (30 Aug 2021)

How did I miss this build. fantastic workmanship. went through this thred & can't wait to see the end product

I used to work as a boiler man ( _stoker_ ) when I was young and fit, we would go to all the potteries
in stoke on trent when they shut down their boilers for cleaning.
It was a dirty wet job, your lungs got full of soot when you went under the boiler to clean out the flues that lead 
up to the tall chimney stacks,I will not go into cleaning the stacks, no health & safty back then..lol
Sometimes the soot and ash was still hot, it was so fine it was like shoveling feathers and the guy in the front had to 
keep up with you as you shoveld it forward.
The boilers pipes get all fury and calculus/limescale forming on the tubes so you would have to get in and set to scaling them 
with a pneumatic air needle gun, took hours to get done & we would work late in the evening as the companys 
only shut down for two weeks.
I went with some guy to change the pipes in a massive boiler at a cole mine it was a nerve racking job knocking out the tubes,
the tool was a steel tube with a locator welded on the end, we all took turns holding it with both hands on the end of the pipe while the other
guy hit it with a sledge hammer to force the tube into the boiler, then we had to do it all over again the other end.
Putting the pipes in is easy, you set them in then you expand the pipe to the boiler plate.
We had just got back to the yard after a job cleaning covered in soot & fred dibnah walks past all he said was "how do, ya been at it then lads".
He wanted a quote for a fire box..  

Sorry to go on but I do not miss old boiler but I like all the models craftsman like you reproduce.
Most of the old boilers had a coat of asbestos as an insulator there was guys who would come in after
us and do repairs to the coating they did not have any protective gear, so you can see where I am coming from
when I say old boilers where dirty polluters...lol


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## Nigel Taylor (30 Aug 2021)

hog&amp;bodge said:


> How did I miss this build. fantastic workmanship. went through this thred & can't wait to see the end product
> 
> I used to work as a boiler man ( _stoker_ ) when I was young and fit, we would go to all the potteries
> in stoke on trent when they shut down their boilers for cleaning.
> ...


Thanks for the kind words, sometimes I have to make a part 3 times to get it right. So, lots of patience. 

Interesting stories about boilers. My grandfather was a stoker on a large boiler at a factory and his dad was a journeyman on traction engine repair and manufacture. These are all tough dirty jobs. Cheers, Nigel


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## Nigel Taylor (31 Aug 2021)

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).


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## hog&amp;bodge (31 Aug 2021)

His work & attention to detail is astonishing, did he teach you how to metal work.?
I had a friend he used to make steam powered cars, his work was outstanding in every detail & like you spend 
days getting it righ. No way would you disturb him when he was on a build..lol
His last project was a steam wire stretching winding machine but he passed away before he finished it, he sad it 
was for the science & industry museum in manchester.

Any way I was given a box of brass nuts, bolts, screws and washers. I was having a rummage through & came across 
these think they are some sort of brass rivets. If you have any use for them I will send them to you.


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## Nigel Taylor (31 Aug 2021)

hog&amp;bodge said:


> His work & attention to detail is astonishing, did he teach you how to metal work.?
> I had a friend he used to make steam powered cars, his work was outstanding in every detail & like you spend
> days getting it righ. No way would you disturb him when he was on a build..lol
> His last project was a steam wire stretching winding machine but he passed away before he finished it, he sad it
> ...


Hi, yes, he taught me metal and wood working from a young age. We made lots of radio control models as well as tools and some mad stuff. The rivets look interesting. if you email me [email protected] I will send you my address. Very kind, thanks, Nigel


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## Nigel Taylor (1 Sep 2021)

Managed to etch a few nameplates today:






I think the bottom right one is the one to use. To put it into scale the capital letters are 1.4mm high.


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## Nigel Taylor (4 Sep 2021)

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. The issue I have so often with this model is the size. The phosphor bronze saddle for the cylinder has all of the ports running through it, so fitting in a valve is going to be tight. 

Also, this part has to survive without any distortion being heated to 745-780°C for hard silver soldering. This is because it gets silver soldered in place first and hence needs to be higher temperature so I don't release the joint at stage two fixing.


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## pe2dave (4 Sep 2021)

Good luck @Nigel Where's the compromise?


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## MARK.B. (4 Sep 2021)

Like a good book,once i started reading the post i could not stoplike the way you tell the story both good and bad and the pictures help my aged grey matter to make sense of what you are explaining (well most of it anyway). Now its time to watch the vid's


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## Nigel Taylor (5 Sep 2021)

pe2dave said:


> Good luck @Nigel Where's the compromise?


Not really a compromise, more concerned about the level of detailed machining that has gone into the saddle. Hence always nervous of next steps such as machining a working steam valve face into it. Plus then finally silver soldering it to the boiler shell.


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## Nigel Taylor (6 Sep 2021)

I've now fixed the nameplate in place using an easy flow silver solder paste.


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## Nigel Taylor (9 Sep 2021)

I've been doing a lot more silver soldering and testing before silver soldering the saddle to the boiler.

1. Flow of silver solder through a joint:






Copper sheets (representing the boiler) and a phosphor bronze plate (saddle) and a phosphor bronze bolt. Flux applied to all surfaces prior to assembly. Then looking at difference between silver solder either side of PB plate versus around the PB bolt head.

I then section the parts.





The bottom section is where the silver solder was applied around the bolt head. This appears to have pulled through the threaded joint better.


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## Nigel Taylor (9 Sep 2021)

2. Silver solder masking - looking at options that allow you to mask areas where you don't want the solder to flow





here I used a graphite pencil (one of those solid graphite ones) and it worked quite well on the copper and brass sheet.




Also, any residue just comes away with 20 minutes in the pickling fluid.


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## Wildman (9 Sep 2021)

amazing skill and patience from start to finish. I look forward to seeing it running. Well done it is certainly an heirloom piece.


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## pe2dave (9 Sep 2021)

Wildman said:


> amazing skill and patience from start to finish. I look forward to seeing it running. Well done it is certainly an heirloom piece.


And that attention to detail? Quite admirable.


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## Nigel Taylor (29 Oct 2021)

I've been stuck for a few months, a total roadblock on how to make the steam valve. Especially as I have machine this into the PB saddle that itself has had lots of hours put into it. Hence it has been collecting dust on my desk and staring at me, annoying me. But, after a clean up of the workshop it is back on the bench. I will solve this problem.



There are a few more items on the list of next things to do on the Burrell


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## Nigel Taylor (31 Oct 2021)

I made the decision to make the steam control valve a remote valve.



The best bit is I made a decision and this allowed me to move forwards. So I could then silver solder the saddle to the boiler.


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## Nigel Taylor (1 Nov 2021)

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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## MARK.B. (1 Nov 2021)

Great to see it all coming together so well for you Nigel, my poor attempts at soldering could never comparebut i am a dab hand at push fit plumbing


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## Sandyn (1 Nov 2021)

Amazing skill and very interesting to see how you have solved problems along the way. It is beautiful!


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## Nigel Taylor (4 Nov 2021)

Machining the double eccentric yesterday afternoon was quite fun. I was prepared for this to be a prototype, but I think it has turned out ok.


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## Nigel Taylor (5 Nov 2021)

Sandyn said:


> Amazing skill and very interesting to see how you have solved problems along the way. It is beautiful!


Thanks, I try to share as much as I can, sometimes though I think people will be bored watching me make something.


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## Sandyn (5 Nov 2021)

Nigel Taylor said:


> I think people will be bored watching me make something.


I never get bored watching things like this, I love mechanical things. You can see how they work and what's going on as the parts move round. I enjoy hearing your thought process as you build the model.


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## Fitzroy (5 Nov 2021)

Nigel Taylor said:


> Thanks, I try to share as much as I can, sometimes though I think people will be bored watching me make something.


Never! Keep up the good work.


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## ecokestove (6 Nov 2021)

I am in awe of people who can do this sort of work.


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## Nigel Taylor (22 Nov 2021)

After a lot of help from a fellow steam model engineer 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.


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## DrPhill (23 Nov 2021)

Incredible work. I have been following with great interest. I can see how you have done things, that is an education in itself.


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## Nigel Taylor (24 Nov 2021)

Back to testing the insulation for the boiler. A quick overview of the object in this short video:



The thermal conductivity of wood versus density is an interesting plot and hence shows why I have used balsa wood as the pads. 






Initially I have done some repeatability testing on the cooling curves. So far these look good.






As you can see, each test takes around 2 hours and so in the meantime I have started making a simple mathematical model of this test object. Let me know any ideas for thermal insulation?


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## Fitzroy (24 Nov 2021)

For the insulation I think it's a balance between theoretical and practical application in such a miniature environment, and also conduction vs radiation.
- A trapped layer of gas would in theory be effective but you would need a decent gap 10mm+ to prevent radiant heat becoming dominant. 
- Glass fibre etc has great performance in theory but once you compress it the performance drops, so how you would maintain effective performance at low thickness would be difficult. 
- PIR or foam type insulation is super effective but getting a good uniform layer would be tough, perhaps spray foam a layer then turn off the excess to get a consistent 3-4mm thickness, then wrap in something for structural protection. Zero experience if this is possible.
- Neoprene could be a good balance of performance and practicality to apply and structural strength.

Brainstorm, perhaps helpful perhaps not.

Fitz.


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## Nigel Taylor (25 Nov 2021)

Fitzroy said:


> For the insulation I think it's a balance between theoretical and practical application in such a miniature environment, and also conduction vs radiation.
> - A trapped layer of gas would in theory be effective but you would need a decent gap 10mm+ to prevent radiant heat becoming dominant.
> - Glass fibre etc has great performance in theory but once you compress it the performance drops, so how you would maintain effective performance at low thickness would be difficult.
> - PIR or foam type insulation is super effective but getting a good uniform layer would be tough, perhaps spray foam a layer then turn off the excess to get a consistent 3-4mm thickness, then wrap in something for structural protection. Zero experience if this is possible.
> ...



Hi Fitz, yes, it is a balance. although the small gap I used on the vertical boiler worked quite well. The Teflon cooking sheets are a good first wrap, although even this eats into my 1.5mm total thickness available.
Some use silicon sheet, but that appears to be a better thermal conductor than teflon. I will have a look at neoprene.
Best regards, Nigel


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## Nigel Taylor (25 Nov 2021)

The unclad versus maximum (is it maximum?) insulation has now been tested and the data shows a significant difference. I think enough to bookend the problem. Quite frankly my test object would be better if it was about 300mm long to make the losses at the ends less significant. However, for now I can test a range of insulation between these bounds.






Also, Boiler heat loss versus published data for copper pipes used in a central heating system shows that there is a close relationship to the heat loss from the unclad boiler.






I've now tested some thinner wraps and multi-layers, just need to do some calculations and I will post this.


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## Adam W. (25 Nov 2021)

I'm loving your attention to detail, it's inspiring to say the least.


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## Gordon Tarling (25 Nov 2021)

Nigel - there are specific insulation materials for model boilers - it normally takes the form of ceramic matting, which is quite flexible and easily cut to size - Page 10 of this catalogue is just one example.

G.


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## Nigel Taylor (26 Nov 2021)

Gordon Tarling said:


> Nigel - there are specific insulation materials for model boilers - it normally takes the form of ceramic matting, which is quite flexible and easily cut to size - Page 10 of this catalogue is just one example.
> 
> G.


Hi Gordon, thanks, hadn't seen that. I have just tested some ceramic matting that I had already, but will get some of this too to test. Best regards, Nigel


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## Nigel Taylor (13 Dec 2021)

The flat smokebox door was annoying me, 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


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## Jamesc (13 Dec 2021)

The smoke box door definately looks better, it would have driven you mad if you hadn't changed it.

James


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## Hodge911 (15 Dec 2021)

WOW AMAZING!!!!!!
you sir are very talented!


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## voyager (29 Dec 2021)

just wow !


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## Molynoox (29 Dec 2021)

Just stumbled across this thread, quite ridiculous what somebody can achieve with enough skill, patience and determination.
Not just the model making but all the theoretical analysis on the boiler design too, just stunning.
I would be interested to know what your actual job is assuming it is something to do with the model making? I'm curious because if I was to create something like this project I would want to be paid about £20k for it and I'm pretty sure nobody is going to pay that, even though it's probably worth that much in ingenuity and hours. Or maybe somebody does pay that, I have no idea. Just curious how this stuff works commercially. You deserve every bit of good fortune you get though! Amazing.
Martin


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## Nigel Taylor (30 Dec 2021)

Molynoox said:


> Just stumbled across this thread, quite ridiculous what somebody can achieve with enough skill, patience and determination.
> Not just the model making but all the theoretical analysis on the boiler design too, just stunning.
> I would be interested to know what your actual job is assuming it is something to do with the model making? I'm curious because if I was to create something like this project I would want to be paid about £20k for it and I'm pretty sure nobody is going to pay that, even though it's probably worth that much in ingenuity and hours. Or maybe somebody does pay that, I have no idea. Just curious how this stuff works commercially. You deserve every bit of good fortune you get though! Amazing.
> Martin



Hello Martin,
Thanks for the kind words. Until very recently I have headed up a battery research and development team. Now I have more time to spend on model making which is great. I've been model making for a long time having started using a lathe when I was 11. However, my background is a degree in physics and from this I worked in acoustics for many years before designing a number of hybrid concept cars. Hence moving to battery research and design. So, I'm a self taught model engineer and I just really like understanding how things work and how to make them. 

I haven't added up the hours that have gone into this model, but far beyond anything I could charge for. I will develop a set of plans for the engine as I think others will want to make it. Although I still have a lot of parts to design and make before I finish. Including a working differential that is being designed in my head at the moment.
Thanks, Nigel


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## Molynoox (30 Dec 2021)

Brilliant, thank you. Good luck with the differential  that won't be easy but I'm sure you will enjoy it. Looking forward seeing it all finished.
Martin


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## Nigel Taylor (9 Jan 2022)

I've now got the door hinge made and the brass plaques bolted to the door. Moving forward again after deciding the flat smokebox door wasn't good enough. 



The Burrell door now has the correct curvature, the brass plaques are bolted to the door and the hinge is in place. Now I just need to add the beam to the smokebox so that this door can be bolted shut.


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## Nigel Taylor (14 Jan 2022)

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


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## Nigel Taylor (21 Feb 2022)

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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## J-G (21 Feb 2022)

Nigel Taylor said:


> ...and I think I have a sensible result


Well I'm sorry Nigel, I don't think you have - on many counts 

First - you haven't achieved a 10:1 - it's close at the real figure of 10.14634 but 10:1 is acheivable.
Second - you have a 41T gear in the train which is a prime number and therefore complex to manufacture needing an accurate progression of 8.780487805° between each tooth. I don't have a solution in my gear-hobber tables for 41T - but I have made one by engraving a sheet of Tufnol on my CNC machine.
You also have a 117T and, whilst not prime, is odd with only 4 factors, needing a progression of 3.076923077° and 29T needing 12.4137931°. All OK if you have dividing plates with 29, 41 & 117 holes but again I don't have a solution for either of these; I can get 29.0013986 

Now I must say that I think that you have done a fantastic job on this engine so I'm not decrying your efforts in any way, but there is a solution to your 10:1 which is a much better 'fit'.

I have had to work from the photo you posted and used that to 'scale' my drawing. I have to assume that the 67.575 measurement is sacrosanct and I can only guess at the absolute centres of the two bearings from your low-res image so you will see from my drawing that I'm out on that by 0.0183mm which will have some bearing upon the dimensions for the location of the lay shaft but I doubt that they will be too significant.




This solution uses tooth counts which are easily manufactured - 25, 48, 100 & 120. Incidentally, I have used a 'clearance' - between meshing gears - of 0.1mm so the physical properties of the gears is :



The 'normal' terms used to specify gear dimentions are Pitch Circle Diameter (PCD) and Outside Diameter (OD) rather than 'radius' or 'Tip diameter'. 'Centre Distance' is of course of prime importance.



I would presume that the ideal location for the layshaft would be in line with the 120T gear - which would be 90° to the bottom edge. My calculations put it at 89.48079° and to make that any more meaningful I would need very accurate information as to the precise distance between the two bearings measured parallel to the bottom edge of the Brass plate - this is the 23.2122 measurment in my drawing which is a simple scale measurment of your photo so subject to all manner of possible errors.  Changing the clearance from 0.1 to 0.2 would have a significant effect upon that angle. It may well be inconsequential but when designing clocks (or any gear train) I try to stick to easily achieved 'in-line' or 90° locations wherever possible.


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## J-G (21 Feb 2022)

I've just noticed that you may not be able to use a 120T gear since that may be larger than the wheel, which would mean that it would foul the ground ! 

Fortunately there is another combination that will still give you 10:1 exactly, still be easier to manufacture, NOT foul the ground and still have a total centre distance greater than the 67.575 dimension. 





I've added the dimension from the top bearing to the lay shaft on this drawing as well.






Here are the ammended gear dimensions.


I do hope that there are no other 'constraints' that I've missed.


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## Nigel Taylor (21 Feb 2022)

Just made the gears for the drive wheels, made 3 off, not quite sure why an extra....






These are 117 teeth 0.5 module. I reamed a 10mm hole in the centre, intention is to make a hub that runs on the axle and is bolted to the wheel. This 10mm hole mounts onto a very close fitting mandrel when machining the outer diameter and cutting the teeth.

I apologise to the clock makers for my very strange number of teeth. I have been trying to get something that doesn't repeat - or at least not very often.


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## Nigel Taylor (21 Feb 2022)

J-G said:


> Well I'm sorry Nigel, I don't think you have - on many counts
> 
> First - you haven't achieved a 10:1 - it's close at the real figure of 10.14634 but 10:1 is acheivable.
> Second - you have a 41T gear in the train which is a prime number and therefore complex to manufacture needing an accurate progression of 8.780487805° between each tooth. I don't have a solution in my gear-hobber tables for 41T - but I have made one by engraving a sheet of Tufnol on my CNC machine.
> ...



Thanks J-G, you have put a lot of effort into these calculations and much appreciated. The 10:1 is not an absolute as I would prefer odd numbers so that the gear teeth don't repeat. I didn't put this as a constraint as it was just something that didn't have to happen. 

Apologies for my description of tip radius and centre distance - I will change these. 

I think the inline might be nicer in some ways, but pulling the shaft closer to the firebox face will help with access to the door.

Thanks, much appreciated, Nigel


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## Nigel Taylor (21 Feb 2022)

117 divisions is 3.0769230769 degrees and I'm using a rotary table with a worm drive that gives 4 degrees per rotation. This then has dividing plates and for this I selected 39 hole plate and then used a step of of per tooth. Hence 30/39 of 4 degrees.

Hope that makes sense, best regards, Nigel


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## Nigel Taylor (21 Feb 2022)

for 41 teeth I will use a 41 division plate and then each step is 2 rotations + 8/41 this then gives a step of 8.7804878049 degrees


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## J-G (22 Feb 2022)

It seems that the only 'constraint' that I had not taken account of is the fact that you 'wanted' odd numbers 

I'm sure there is a sensible reason for that but it's way beyond my comprehension. It just seems to go against all my engineering training and logic but it is gratifying to see that you have the means to create the 'odd' gears that you have perfectly logically selected.

No need for an apology regarding the 'technical' descriptions - I've spent many years leaning 'engineer's speak' and am naturally a pedant  - - you should use whatever descriptions that you find work for you, even I eventually fathomed what you meant!

It so happened that I had some time on my hands today since a choir rehearsal had been cancelled so applying myself to interesting calculations was a welcome distraction.


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## Nigel Taylor (22 Feb 2022)

J-G said:


> It seems that the only 'constraint' that I had not taken account of is the fact that you 'wanted' odd numbers
> 
> I'm sure there is a sensible reason for that but it's way beyond my comprehension. It just seems to go against all my engineering training and logic but it is gratifying to see that you have the means to create the 'odd' gears that you have perfectly logically selected.
> 
> ...



The odd was just to ensure no repeat as it's for a gearbox. No real need as it will not do much work. The dividing head is a Warco HV4 rotary table with dividing plates on the input. Not as good as a much larger dividing plate that I can fit on the back of the lathe head to do more precise divisions. However, that is more limited in numbers.

Had a look at your website, some great items on there. Thanks for the time doing the calcs, it was good as it made me double check the numbers as I must admit I thought I might have rounded off the calculation to get to 117.


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## J-G (22 Feb 2022)

Glad you consider my input useful - and thanks for the kind comments regarding some past work.

Like any 'tool' a dividing head is only as good as the operator. As long as you always work in the same direction and not go past the hole required and then just turn back you should be OK.

Gearing ratios do need careful assessment and of course they are resticted to integer numbers, so often I've wanted a ½ or ¼ tooth !  

Rather than intrude further into your thread, I'll send you a PM.


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## Fergie 307 (24 Feb 2022)

Nigel Taylor said:


> After a lot of help from a fellow steam model engineer I've managed to make and silver solder the boiler end plate stiffeners in place.
> 
> 
> 
> ...


Never tried doing this in a kiln, but for normal work they do a particular flux for when you need it to work over a long period of heating. Can't recall the name now without going to the shop and looking at the jar. Might be worth trying though. Regular flux only tends to work for quite a short time, sustained high temperatures cause it to burn.


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## Fergie 307 (24 Feb 2022)

Nigel Taylor said:


> Thanks, I try to share as much as I can, sometimes though I think people will be bored watching me make something.


Never boring, keep them coming loving every minute of it !


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## Fergie 307 (24 Feb 2022)

Nigel Taylor said:


> An image of saddle silver soldered to the boiler.
> 
> 
> 
> ...


lovely joint, was that masked with the graphite, or some other method?


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## Nigel Taylor (27 Feb 2022)

Fergie 307 said:


> lovely joint, was that masked with the graphite, or some other method?


thanks, yes, used a graphite pencil and created a mask with it - this works rather well and is very easy to do and to clean up afterwards


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## SamG340 (27 Feb 2022)

Nigel Taylor said:


> Until very recently I have headed up a battery research and development team.



Hi Nigel fantastic work, amazing really. Not sure if this has already been asked but are you making a working model? Is it going to be a coal burner ?

Also sorry to go off topic here

Right now as I'm sure you know batteries are too heavy, take too long to charge up and don't last long enough , even LI are pretty naff when it comes down to it. I was wondering if there's anything interesting in the pipeline for batteries in the near future?


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## Nigel Taylor (27 Feb 2022)

SamG340 said:


> Hi Nigel fantastic work, amazing really. Not sure if this has already been asked but are you making a working model? Is it going to be a coal burner ?
> 
> Also sorry to go off topic here
> 
> Right now as I'm sure you know batteries are too heavy, take too long to charge up and don't last long enough , even LI are pretty naff when it comes down to it. I was wondering if there's anything interesting in the pipeline for batteries in the near future?


Hi Sam, it's a working model. Coal maybe, although gas might be easier. I would like to run it on coal, if just once. But the whole thing is quite small and losses don't scale well.

Batteries, there are no significant changes coming. Everybody is working to reduce the package overheads, this will help. The main drive though has been on cost to bring it comparable to IC. The other axis of the problem is energy consumption: smaller and better aero, improved motor efficiency (peak efficiency is good and around 94%, but we don't drive there often), silicon Carbide inverters will migrate from the exotic down to normal cars. So, don't expect a step change, but improvements on all fronts. Plus buy the smaller sized vehicle, not 4x4 monsters that will always be power hungry.


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## SamG340 (27 Feb 2022)

Nigel Taylor said:


> Hi Sam, it's a working model. Coal maybe, although gas might be easier. I would like to run it on coal, if just once. But the whole thing is quite small and losses don't scale well.
> 
> Batteries, there are no significant changes coming. Everybody is working to reduce the package overheads, this will help. The main drive though has been on cost to bring it comparable to IC. The other axis of the problem is energy consumption: smaller and better aero, improved motor efficiency (peak efficiency is good and around 94%, but we don't drive there often), silicon Carbide inverters will migrate from the exotic down to normal cars. So, don't expect a step change, but improvements on all fronts. Plus buy the smaller sized vehicle, not 4x4 monsters that will always be power hungry.



Brilliant good answer thank you very interesting. I keep an eye on the thread I'd love to see it up and running one day


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## Fergie 307 (28 Feb 2022)

Nigel Taylor said:


> thanks, yes, used a graphite pencil and created a mask with it - this works rather well and is very easy to do and to clean up afterwards


Thanks, I will have to try that. Can't wait to see it running. Particularly like the script on the box door, lovely work.


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## Nigel Taylor (1 Mar 2022)

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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## J-G (1 Mar 2022)

A good first 'guess' Nigel. As I've already said - Bevel Gearing is a different animal - You say that you cut both the Pinion & the Wheel at 20° but I calculate that the Pinion should be at 10.39° and the Wheel at 79.61°. (90 - 10.39)

Your selection of 11 Teeth for the Pinions I assume is due to dimentional contstraints but I suspect that you can actually benefit from using the easier to manufacture 10T Pinion which would reduce the overall width of the Diff. by ½mm. Though that does presume that the main gear is no more than 3mm thick!

Using 10:60, the Pinion Pitch Angle will be 9.46° and the Wheel PA 80.54° - so you would probably get away with 9.5 & 80.5 - correcting these angles in your next attempt will probably solve the 'binding' that you are experiencing.


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## Nigel Taylor (1 Mar 2022)

J-G said:


> A good first 'guess' Nigel. As I've already said - Bevel Gearing is a different animal - You say that you cut both the Pinion & the Wheel at 20° but I calculate that the Pinion should be at 10.39° and the Wheel at 79.61°. (90 - 10.39)
> 
> Your selection of 11 Teeth for the Pinions I assume is due to dimentional contstraints but I suspect that you can actually benefit from using the easier to manufacture 10T Pinion which would reduce the overall width of the Diff. by ½mm. Though that does presume that the main gear is no more than 3mm thick!
> 
> Using 10:60, the Pinion Pitch Angle will be 9.46° and the Wheel PA 80.54° - so you would probably get away with 9.5 & 80.5 - correcting these angles in your next attempt will probably solve the 'binding' that you are experiencing.



Hi JG,
Thanks for the calculation. Can I ask what diameters you calculated these at? The 60T crown is 34.2mm in diameter and at 20° and the pinion was at 7.66mm and again 20°

looking at the 80.5 and 9.5° I can set the rotary table at 80.5° for both gears and that will be good.

Thanks, Nigel


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## Nigel Taylor (1 Mar 2022)

Nigel Taylor said:


> Hi JG,
> Thanks for the calculation. Can I ask what diameters you calculated these at? The 60T crown is 34.2mm in diameter and at 20° and the pinion was at 7.66mm and again 20°
> 
> looking at the 80.5 and 9.5° I can set the rotary table at 80.5° for both gears and that will be good.
> ...


just ran calculation and looks like 7.5mm OD for the pinion and 32.5mm for the crown wheel


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## J-G (1 Mar 2022)

The OD is not the most important figure. The PCD is imperative as far as good mesh/running is concerned. 






This shows the nominal PCD (MOD 0.5) -- 60T = 30mm & 10T = 5mm

To some extent the OD can be whatever you wish and will depend upon external factors.

I doubt that you have considered using ball bearings in the Pinions but I've drawn in a 3mm OD, 1mm Bore, 1.5mm wide option.


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## Nigel Taylor (7 Mar 2022)

I have to firstly say a huge thanks to JG for sorting out the angles and cutting of these bevels. 

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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## J-G (7 Mar 2022)

You're welcome Nigel - I more than doubled my knowledge of Bevel Gearing during the excercise.
I could suggest that fitting a 'fence' with a Sine Bar would be better than a line scribed in engineer's blue though 

Edit : I hadn't read your 9½° write up when I wrote that!


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## Nigel Taylor (3 Apr 2022)

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. 



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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## Nigel Taylor (3 Apr 2022)

I thought that this little differential warranted a bit longer video showing it in more detail as I assemble it



This has taken me some time to design, machine and re-machine. Thanks to JG for the calculations on the angles.


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## J-G (4 Apr 2022)

Excellent work Nigel. Great idea to run the assembly on the lathe to 'run it in'. The difference in the noise level (before and after) is palpable! In use of course it won't run at anything like the speed of the lathe


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## Nigel Taylor (5 Apr 2022)

J-G said:


> Excellent work Nigel. Great idea to run the assembly on the lathe to 'run it in'. The difference in the noise level (before and after) is palpable! In use of course it won't run at anything like the speed of the lathe


Thanks JG, agree, in use these gears will only move a small amount. They just needed to lose the slight lumpy feel and the lathe worked well.


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## Nigel Taylor (15 Jun 2022)

Just machined a solid phosphor bronze rear axle for the Burrell. OK, this isn’t a solid rear axle like a 1960’s muscle car. This is an actual solid round phosphor bronze bar that supports both rear wheels to rotate independently and then the differential sits on a separate layshaft.






and then just so that you get an idea of the scale


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## pe2dave (15 Jun 2022)

I'm glad you put your hand in the shot, give it some scale  
Not the right word, but it's beginning to look pretty.


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## sawtooth-9 (17 Jun 2022)

W


J-G said:


> Well I'm sorry Nigel, I don't think you have - on many counts
> 
> First - you haven't achieved a 10:1 - it's close at the real figure of 10.14634 but 10:1 is acheivable.
> Second - you have a 41T gear in the train which is a prime number and therefore complex to manufacture needing an accurate progression of 8.780487805° between each tooth. I don't have a solution in my gear-hobber tables for 41T - but I have made one by engraving a sheet of Tufnol on my CNC machine.
> ...


Whats the problem with prime number gears ?
If you have the correct OD of the blank, the correct cutter and set your dividing head correctly - where is the issue ?


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## J-G (17 Jun 2022)

sawtooth-9 said:


> Whats the problem with prime number gears ?
> If you have the correct OD of the blank, the correct cutter and set your dividing head correctly - where is the issue ?


The issue is purely down to the fact that Prime numbers give less options or require more generating gears to be available. I will say that my opinion comes from the fact that I use a Gear Hobber rather than a Dividing Head but even then how would you cut a 41T Gear if you didn't have a 41 (or 82) hole plate?

If you had plates with every hole count from 5 to 120, the options open to you for (say) a 28T gear is 15, change that to 29 and the options drop to 3. This assumes that you have a 40:1 ratio Dividing head, if you have a 60:1 the 29 options drop to 1. In real life a well equiped workshop might have 6 or 8 plates with 5 or 6 hole counts so something between 30 & 48 choises (rather than over 100) and, whilst I agree that most of them are likely to be Odd, if not Prime, there is still a limit to the number of options.

Bottom line is that by chosing Prime Numbers for Gear Teeth you are restricting your options as to means of manufacture. I don't say that the issues are insurmountable, just restictive.


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## Nigel Taylor (17 Jun 2022)

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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## Digger58 (18 Jun 2022)

Nigel Taylor said:


> I spent Saturday afternoon adding the beading to the edge of the tender. It's not perfect as half-round brass beading tends to rotate as you try and bend it flat around corners. I should have made some jigs.
> 
> 
> 
> ...


Bought a tin of that about 2 years ago in a very old fashioned shop in west Clare here in Ireland.


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## Nigel Taylor (18 Jun 2022)

J-G said:


> The issue is purely down to the fact that Prime numbers give less options or require more generating gears to be available. I will say that my opinion comes from the fact that I use a Gear Hobber rather than a Dividing Head but even then how would you cut a 41T Gear if you didn't have a 41 (or 82) hole plate?
> 
> If you had plates with every hole count from 5 to 120, the options open to you for (say) a 28T gear is 15, change that to 29 and the options drop to 3. This assumes that you have a 40:1 ratio Dividing head, if you have a 60:1 the 29 options drop to 1. In real life a well equiped workshop might have 6 or 8 plates with 5 or 6 hole counts so something between 30 & 48 choises (rather than over 100) and, whilst I agree that most of them are likely to be Odd, if not Prime, there is still a limit to the number of options.
> 
> Bottom line is that by chosing Prime Numbers for Gear Teeth you are restricting your options as to means of manufacture. I don't say that the issues are insurmountable, just restictive.


Hello J-G and all, 

Thought I would share the calculations for the HV4 rotary table and dividing plates. The excel calculation sheet is available as a free download: workshop calculations The full sheet allows you to enter the division plate divisions and then highlights the options that work for divisions up to 200. 

The Warco HV4 and dividing plates is quite good as it comes with 3 plates and they have divisions of: 15, 16, 17, 18, 19, 20, 21, 23, 27, 29, 31, 33, 37, 39, 41, 43, 47 and 49 and thus give you the list as shown below:






Sadly 28 and 44 are missing. A quick play with the sheet and if I make up a 44 and 56 hole plate I can solve this (obvious really)






I know someone is going to point out the small errors at 6 decimal places, but for me this works. Please do download for free and have a play or use or comment. Thanks, Nigel


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## J-G (18 Jun 2022)

Hi Nigel, you will naturally understand that I also created a spread-sheet to determine my data  - no where near as sophisticated as yours but sufficient to demonstrate that 'Prime' is more complex.

It's interesting to see that the lack of two *even number *hole-count plates makes even number divisions a problem. A 14 & 22 would solve it as well of course (or a 7 & 11)

If the D/Head were 40:1 rather than 90:1 then 28 would have 2 solutions (21 & 49 hole) & 44 just the one (33) but may not have as many other solutions - I haven't done the research


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## Nigel Taylor (18 Jun 2022)

J-G said:


> you will naturally understand that I also created a spread-sheet to determine my data


Hi J-G, I thought exactly that. At some point I will probably make another plate, but as with most things I will probably leave that until I need it. Cheers, Nigel


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## Nigel Taylor (19 Jun 2022)

A short video showing me using the indexing feature I built into the table support on my miniature pillar drill.


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## J-G (19 Jun 2022)

Excellent concept Nigel. It's always easy to 'improve' upon an idea created by someone else - having the original idea is the difficult bit  

As you are aware, I am obsessed with precision, so the use of a '_bit of springy piano wire_' did grab my attention. I can see that you need to alter the vertical position of the 'Detent' to select the 6, 8 or 10 hole level so piano wire for the arm seems perfectly valid. The [Detent] on the other hand might be better - in terms of accurate repeatability - if it were more substantial & tapered so that it fits more 'snuggly' into the Indexing Head holes.

You may already have taken this into account but you don't actually say so and the detent does not look to be anything more than another '_bit of springy piano wire_'


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## Nigel Taylor (20 Jun 2022)

J-G said:


> As you are aware, I am obsessed with precision, so the use of a '_bit of springy piano wire_' did grab my attention.


I think I lean towards the more 80:20 rule and get to a point where it is good enough for what I want and move on. However, that does cause me issues, as demonstrated by the traction engine where my design and make as I go along is starting to catch up with me. The tolerance stack at this scale is building and I'm going forward one step and backwards two.....


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## AES (20 Jun 2022)

Nigel Taylor said:


> I think I lean towards the more 80:20 rule and get to a point where it is good enough for what I want and move on. However, that does cause me issues, as demonstrated by the traction engine where my design and make as I go along is starting to catch up with me. The tolerance stack at this scale is building and I'm going forward one step and backwards two.....



I've been following this thread for some time and I must say Nigel, that IN GENERAL, I agree with you in principle - "near enough is good enough" - a lot of the time anyway.

And your lovely looking traction engine project epitomises that approach. And normally, "we" don't see the problems unless and until you've pointed them out. (Hugely looking forward to seeing it in steam BTW).

But with a current project of my own (nothing "fancy" or "clever" like yours) where I've applied the same "near enough is .... " approach, this IS beginning to bite me in the posterior!

While I can understand and fully appreciate member JG's approach ("... to 4 places of decimals" - I'm now paraphrasing both you Nigel, and JG too of course), with my job in the final assembly/after painting stages I AM finding some places where parts that should move smoothly together are binding a bit, while on the other hand, some parts that should fit together snugly simply don't! Both of those lead to some reworking followed by, most probably, at least paint re-touching, if not full repainting!!!

Both lead to some frustration and extra time needed to finish (especially as I'm definitely NOT a lover of painting)!

So it seems to me that the best of both worlds would be to combine the 2 approaches - i.e. use ".... to 4 places of decimals......"; NOT where it's not necessary but where it definitely IS; while using "near enough ......" where I can get away with it.

The trouble is that like my project, IF it's the first and the last time I'll do a job like that, then I don't always know/understand whereabouts in the job the 2 approaches are the correct approach - UNTIL IT'S TOO LATE that is!

I guess it's called "experience" and to me anyway, that's one of the attractions of trying to make almost anything. (Well sometimes/mostly it is, anyway)! 

OK, no "value" here. Just "philosophising", FWIW


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## Nigel Taylor (20 Jun 2022)

AES said:


> "near enough is good enough"


The phosphor bronze axle is 1/4" and machined down to 6mm OD for the wheel bearings. I checked them on the mic and measured 5.99mm and 5.98mm for left and right. They should be good enough.


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## Nigel Taylor (9 Nov 2022)

Finally the Burrell is back on the workbench and I've made the connecting rod from 3 parts

Here with the phosphor bronze big end in place. Hopefully the matchstick gives you an idea of scale.











The conrod was assembled from 3 parts





Finally with the conrod in place





let me know what you think or ideas


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## Molynoox (9 Nov 2022)

Nigel Taylor said:


> Finally the Burrell is back on the workbench and I've made the connecting rod from 3 parts
> 
> Here with the phosphor bronze big end in place. Hopefully the matchstick gives you an idea of scale.
> View attachment 146886
> ...


If I keep learning I should have caught up with your skill level in about 20,000 years


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## Nigel Taylor (10 Nov 2022)

Molynoox said:


> If I keep learning I should have caught up with your skill level in about 20,000 years


my dad bought me an Emco Unimat 3 when I was 11 years old and taught me how to machine, 45 years later and I'm still learning, still making mistakes

my machining is way behind the work I see from tool makers, but I enjoy my time in the workshop


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## Nigel Taylor (13 Nov 2022)

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







The two eccentrics gives the ability to run the steam engine in forward and reverse. I need to make up the slider, crank and handle etc

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


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## Nigel Taylor (30 Nov 2022)

The differential sits on the layshaft and this takes a bit of thinking about. Hopefully the following image helps. More details of the ratios here: Burrell Crankshaft and Layshaft Gears - glue-it.com






The drive and neutral is achieved by sliding the crankshaft gear out of mesh.



Lots more to do, but gradually getting closer to completion.


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