The Unofficial Mamod and Other Steam Forum

Roly Williams · Posted: Sun Aug 02, 2009 12:03 pm Post subject: Sussex Steam Newcomen engine

As requested by a couple of people, I'm keeping a log / diary of the assembly of this engine.

The engine is a Sussex Steam Newcomen engine. It comes as a kit of materials with instructions. It comes in a plain box with a picture on the lid. No money wasted on flashy packaging on the outside, but inside it was well packed with plenty of bubble wrap and poly chips.

Small parts were in plastic bags and the larger parts were individually wrapped.

First off in the instructions was the boiler. The main part of the boiler comes pre-formed. I suspect it is originally intended to be something like an oil can or spray can of some kind. It's a nice appropriate shape, anyway. Turning it into a functional boiler was fairly simple, with only a couple of minor problems. A hole is drilled into the top cap and a short length of pipe is soldered in. This is then soldered into the top of the "can".

The next bit is the tricky bit, i.e. the two holes for the SV and overflow plug. The clue is in the instructions, which say "Make a 7mm hole ...". It doesn't tell you how to do that. Drilling a 7mm hole is not an option because the brass is too thin. I started off by drilling a very small hole. As predicted, it snagged and produced a very ragged hole. That didn't matter because I then opened up the hole with a round file which, as it happened, was just the right diameter. The idea then was to solder a 6mm brass nut over each hole. I did this for the first one but when I came to do the second one, I couldn't find it. Either it was missing or I had lost it. I had plenty of spare 6mm nuts but not brass ones, they were all steel (not a good idea on a boiler). Searching through my odds and sods box, I found a couple of brass bushes of just the right size. In fact one of them even had the correct thread already tapped, the other had a suitable sized hole which I had to tap myself. I then had to open up the holes to take the bushes. I couldn't use my original method because I don't have a round file of the right size. I then remembered that I had this tool which I've rarely used:

The brass is thin enough to use this in the hand rather than in a drill, which would probably have been too brutal.

With the holes "made" and bushes soldered in, the next step was the safety valve. A 6mm brass bolt is supplied which has to be cut short and drilled through the centre. A 3mm bolt is then fitted with an O ring, spring and nut in the traditional manner. The nut has to be filed down so that it will pass through the hole on the bush. This was a bit fiddly because it's so small. Eventually, I worked out a method whereby I fitted the nut on the bolt, along with a second nut to lock it in position, which I then put into the drill chuck. It was then a simple task to file the nut down to size.

The SV and the overflow plug (another 6mm brass bolt) are then screwed in place with fibre washers.

The next step was the firebox, or boiler stand as they call it. This is made from thin brass sheet with sections cut out and holes drilled for pop rivets. A template is supplied in the instructions. It was a bit tricky making the cuts with sheers. The outer cuts of each section were easy enough but the middle cut in each was not so easy. I cut them close with right and left handed sheers and then filed them to the line. The two sections are then pop riveted together.

The boiler sits on top with no fixing.

That's as far as I've got so far. "Watch this space".
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Roly Williams

"God is not dead - he is alive and well and working on a much less ambitious project" (MRFS)

Alf · Posted: Sun Aug 02, 2009 1:51 pm Post subject:

Can't wait to see it in action.

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IndianaRog · Posted: Sun Aug 02, 2009 2:05 pm Post subject:

Roly, lookin' good so far. I do believe that "boiler" began life as one of those brass sprayers for plants and the like. Seems to fit the bill fine, though I can imagine the thin brass was a right pain to drill without tearing.

Now, get back to working on it!
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Dampfmaschine · Posted: Sun Aug 02, 2009 2:59 pm Post subject:

Sure looking good

- strange the supplier puts so much effort in to the packaging whilst the instructions seem less than adequate

tmuir · Posted: Sun Aug 02, 2009 3:09 pm Post subject:

Nice work so far Roly.
I remember having to drill a small brass bolt to make a filler plug for my Bing loco before I had my lathe and that was a pain in the but to do and get it central so I feel for you with that part.

I'm interested to see how this thing runs as its a very interesting looking engine.
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A nice example of an Australian made Scorpion Donkey Engine

gremlin · Posted: Sun Aug 02, 2009 3:39 pm Post subject:

Looking good, I'll follow this thread and see how it turns out. I'm guessing my little oscilator was made by them as the safety valve is just the same.

Keep it coming

Roly Williams · Posted: Sun Aug 02, 2009 3:52 pm Post subject:

Roly Williams · Posted: Sun Aug 02, 2009 4:01 pm Post subject:

metalhead100 · Posted: Sun Aug 02, 2009 6:16 pm Post subject:

I have looked at their stuff but was a bit put off by the plastic as part of some of the kit....(different engine).

Nice work so far Roly .....

There is a vid on youtube of it running...

http://www.youtube.com/watch?v=QFio0J4Psuc

Jim
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Roly Williams · Posted: Sun Aug 02, 2009 6:37 pm Post subject:

steamyjim · Posted: Sun Aug 02, 2009 6:44 pm Post subject:

BK · Posted: Sun Aug 02, 2009 9:21 pm Post subject:

Very interesting Roly, nice work too.
I like the tapered "router" I think I have one somewhere, didn't thing to use it like you did though.
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BK

nothing like letting off steam

Bugsy · Posted: Sun Aug 02, 2009 10:45 pm Post subject:

Should be a real eye-catcher when it's finished, Roly.

Steve_S · Posted: Mon Aug 03, 2009 8:04 pm Post subject:

Its going to be an interesting one Roly! I must say Ive looked at those brass spray can things in the past and wondered if one could be used for a boiler, so I will be interested to see how it goes.

Sandman · Posted: Mon Aug 03, 2009 8:11 pm Post subject:

Following this with interest Roly.

Keep up the good work.
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