I never liked the reverser I'd made, and after making the brake control lever, I realized it was much
too short.
On top of that it was crude and had no return spring so I had to come up with a new design.
There is no evidence of the size or shape on the original GA so I eventually came up with this one.
The pulling handle is made from two pieces of 2mm thick sheet and then bent to shape and silver soldered.
It could really do with more spring space, but it works quite well once I'd allowed for the sideways
movement of the rod.
The chap who made the smokebox barrel had to have two goes before he got the size right and he gave me
the first attempt, which was fortunate. It wasn't fully rolled, so I could cut a section out and the
curve was just about perfect to use for the saddle.The base is just a simple box section welded together with part fitting between the frames and the other two sides resting on top of the frames. I clamped the saddle to the box and drilled through the smokebox. After that it was a simple welding job on the inside of the box section. I hope I've got the height right although not difficult to raise if it's too low but somewhat harder if too high. I've matched the four bolts each side which bolt the saddle to the barrel, as per full size. Cutting the holes to allow the vertical pipes for the inlet steam to pass through, proved to be hard work with much filing!
Cutting across 150mm width of 3mm steel when in a barrel shape would normally have been quite difficult but I have a small plasma cutter which did the job in seconds albeit, rather roughly. I find it very useful at times but the hard part is keeping the movement steady. When it is steady, the results are comparable to a rough laser cut. As I haven't had much practice with it, I'll no doubt improve. I'm hoping to make a simple jig which will allow me to cut the rings round the windows.
I silver soldered a threaded piece of brass into the blast nozzle junction so that the blast nozzle
can be screwed into it. I also threaded the outer edge so that a sealing ring can be screwed down on to
a seal and make a rigid joint. The length of the blast pipe has yet to be determined. The same piece
of rolled plate also came in handy for making the chimney. I suppose I should have had a casting, but
as I had a suitable piece of steel pipe which was very thick, I made a considerable amount of swarf
instead. I welded the plate to the pipe and built up the curve with the mig welder. I think this part
would have been quite difficult to cast. I wanted to make the chimney as close to the original as
possible and the end product isn't too far off. What I have yet to do, is make the cap to fit the top.
The original was all in one but I fancy going to a copper top but I've not got the material at the
moment. I will have to make one casting though, and that is for the smokebox door. The full size is
made up of layers bolted together which I thought about but decided I couldn't make a dished outer which
would need to be at least 3 mm thick to take the load of the clamp to shut the door tight.
Making this cover for the steam inlet pipe was quite tricky to get right. In the end I made a copy
out of aluminum using trial and error methods after having worked out a basic shape. When I'd got
this right, I flattened it and used it as a template to make the final in brass. This is as near to
the original as I could make it appear. The full size doesn't have a saddle as my design has. It is
quite short and the extra piece is part of the cover. This would have been much harder to make and
the appearance would be just the same in the end.
The drawing for full size doesn't show the cleading on the cylinders, so I've had to go by photographs.
The whole cylinder block and steam chest is covered including the front and rear. What isn't clear is
how far down the end cleading goes.
Neither does it show how the whole lot is fixed to the cylinder.
So I've kept the appearance as close as possible and used 1/16" rivets to hold the panels together.
The cover base bolts to the top section and in turn is bolted to the saddle. Small screws fix the
side panel into tapped holes on the cylinder and the whole becomes very rigid. How to paint the
colour scheme will need some thought.
The smokebox door full size is made up from 3 layers which are separated with spacers. Making this to scale would not be easy, and might not be strong enough to take the clamping effect of the handle. On top of that, the outer would need to be dished which, in steel is beyond my workshop equipment. So, like most others, I've opted for a casting. I could have had it done in cast iron, but I hate the muck it causes in the workshop, so I'm having it cast in aluminium. In the meanwhile, I'm trying to finish off all the other little jobs.
The front damper is controlled with a simple lever system and the set up I've made is very much like
the full size. I can't complete any of the levers until I have the boiler in place and possibly the
side tanks as well.
I thought I'd try it on air as it seemed to be very stiff when I needed to
rotate the wheels to get clearance. I lowered it on the trolley, blocked up the wheels, and
hoisted the rear end so that the front end stayed in contact with the rails and the leading wheel
just clear. I had to turn the compressor up to full (110 psi) to get the wheels to turn and after
a time they still rotated when the pressure had dropped to about 40psi. I had greased all the bearings
with liquid grease via the ends of the axles. I'd put it in under pressure to make sure the needle
roller end rings had not got turned the wrong way on fitting. At the end of the session the grease
was coming out everywhere!
These fiddly little boxes supply the oil to the bushes in the centre of the bogie. They are not difficult
to make, just awkward to hold when silver soldering all edges at the same time. I happened to have a
piece of copper tube with a 1/16 hole which made an ideal hinge. When soldering the hinge, the difficulty
is to not let the solder run into all three pieces of tube. I solder the two outside pieces first to
the lid with all three pieces in place and the centre rod holding them together. Everything I don't
want soldered is covered in Tipex. This works well, can stand the heat and comes off easily when
dropped in the pickle hot. I then clamp the lid in place, apply more Tipex and solder the centre piece
to the body. The catch is soft soldered in place. Inside, are two cups connected to copper pipes
which will be connected to the bushes with plastic tubing at a later date.
I changed my mind about connecting with plastic tubing; it looked completely out of place and would
probably wilt from the heat of the smokebox. I have now joined up with copper pipe which shows in
the rear picture of the smokebox.
I decided on having the smokebox door cast in aluminium, firstly because it's much cleaner to work
than cast iron and secondly to keep the weight down. There is already quite a weight on the front bogie
from the cylinder blocks. There was little to do to the front face as it was just about
the right size but the back face was more difficult.
I'd allowed too much material on the door insert
which should have been a little thinner than the smokebox front ring. I'd shaped the inside as well
because the thickness was greater than the length of my 3/16" rivets. Not enough though, and so this
also needed turning. The problem was how to hold the door curve side in the chuck. The chuck (8")
was big enough but fouled the bed when reverse jaws were used. In the end, I had to make up special
shaped clamps and clamp it to a face plate. Trouble was, the faceplate was too small. In the end,
I used the round table from the small pillar drill which was exactly the same size as the door.
I had to machine the insert off because the extra thickness prevented the locking bar and dart from
clamping the door shut. Biggest problem was chatter.
The hinge was not too difficult to make but when I've made them before I riveted them in place and
found that the bars were not really pulled up tight to the curved face. Although the bars were bent
to fit reasonably well, a gap did appear in places. This time I used bolts, but to look like the
full size, I turned them to have domed heads hoping that they would not slip on tightening - they didn't.
I didn't go to the trouble of making an arrow head on the dart; just a cross bar. The rear view
of the smokebox shows the locking bar and the dart. Hopefully it should provide a tight fit. The
handles on the door look a little on the small side but they are to scale.
I know the full size didn't have a copper top but they do look good! It took me three days to make. I had barely enough copper sheet and had to make do with three pieces joined. I lost count of the number of times I had to anneal the copper. It only takes a few clouts from the mallet to harden it again. I used lots of bits to make up the ring in the centre and the whole lot was silver soldered to a brass tube which I had carefully machined to fit the chimney and was a sliding fit; just. I did make the beginner's mistake of offering up the chimney to the brass tube. The tube was hot, the chimney cold. The chimney went in 5 mm and then of course became a shrink fit. Foul language filled the air. However, all went together and held in the chuck with jaws on the inside and to steady the other end I have one of those most unusual tools; a rotating chuck which fits the tail stock. The ring was turned and the whole thing shaped and polished. Not a perfect shape, but then hand forming was bound to show some inaccuracies. Not easy to spot when fitted. The interesting thing was that my carefully machined brass tube once a sliding fit, now became a drive fit. At least nobody will be able to pinch it. The only thing against this method of construction is that the silver solder lines show up, especially when the copper takes on a tarnish with the heat. Other than copper plating, I can't think of a way to avoid this. Biggest problem I have at the moment is a slight list to starboard!