As someone with possibly more projects on the go than what is good for me, I thought perhaps I'd better post one of them.
Especially as I've been neglecting Newnes to concentrate on this one.
Of all the types of steam engines, it's the marine engine that holds the most fascination for me.
I think it's the sheer variety of types as engineers tried to solve the problems of space, high centres of gravity, size to power ratio, economy etc..that appeals to me.
Sothern will be a compound diagonal paddle engine.
it's based on a drawing in 'Sotherns verbal notes And sketches for marine engineers' - hence the name!. I've always wanted to build this engine but the drawing in the book is quite small.
Fortunately,
www.archive.org have digitalised it
https://archive.org/stream/verbalnotessketc00sothrich#page/2/mode/2up and by clicking on the enlarge button I can get a better understanding of the drawing.
the other reason is that in the Liverpool maritime museum there is an exquisite model of this type of engine that I often go and .. well... drool over!
so at least I have a real 3D model to go and compere the diagrams too.
As for drawings, well, I just enlarged the diagram until the frame filled the window, held a sheet of paper over the screen and traced the outline.
I'm not one to let the lack of detailed drawings get in the way of hacking at metal!
And so to the hacking.
First up are the frames. the two outside frames I made from 5mm plate while the inner is from 6mm.
for me , with no milling machine, it's a case of hacksaw and file.
the webs are 2mm thick strips. they were arkward to hold in place so I tack-welded them, then soldered them and used my trusty proxxon to grind out the welds.
the real problem was to get the holes for the bearings , flat surface for the crosshead rails and feet all in line with each other.
to do this, I made a crude jig to hold each frame. I first drilled the holes , as best I could, for the main bearings in each frame, and a corresponding hole to take a peg in the plate. cheeks were drilled and soldered either side of the holes in the frames. then, on one frame, I tacked the plate for the guide rails in place, then fitted the frame onto the jig.
I then held a block against this and welded it to the jig plate. this way , if I slid another frame over the peg and clamped a plate against the block and tacked it to the frame, I stood a good chance of getting the crosshead plate in the same relative position on the other two frames.
I also set up a similar block for the feet. Although I used a long bar , tacked it to both legs, then after soldering, cut out the middle section.
here's the jig in use
after the three frames were done it was time to see how close they were to each other.
some of the webs aren't exactly square
and the legs aren't all the same distance apart - well I am a sort of 'near enough is good enough' muddling model engineer!
and I must have been quite careless in clamping the bar for the feet on one of the frames
BUT, the plates for the rails came out quit good. the middle one is slightly forward of the two outer ones but all three are at the same angle which I think is probably more critical than a wonky foot, which I corrected by buiding up with weld and filing down.
with a 15mm bar through the bearing holes, there was very little fettling of the feet to get all three frames sitting flat with no rocking of any one of them.
thanks for looking
peter
