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)

 

[dnalot]

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

Mark T

 

[glue-itcom]

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

 

[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.

 

[NickP]

Look forward to following along Nigel. HGood work

 

[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.

 

[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.

 

[glue-itcom]

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.

 

[glue-itcom]

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

 

[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.

 

[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.

 

[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...

 

[glue-itcom]

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

 

[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.

 

[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

 

[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.

 

[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.

 

[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.

 

[shorrog]

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

 

[glue-itcom]

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