Part 28– Plumbing, injecting some reality – A solution
So I implemented option 3. (see previous post) Option 3, an exercise in cutting, filing and drilling in confined spaces.
This option required me to cut off the steam and water feed pipes fitted to the injectors in part 26
and drilling them out, so I ended with up two holes instead. Into these holes, pipes attached to the chassis plug in as the chassis is fitted to the body.
This was not, I admit, all that obviously an attractive option, but much thought and an abortive attempt at option 2 persuaded me this was the way to go. None the less. I started into it with considerable trepidation as to how easy it was going to be. Given de-soldering things usually means getting them significantly hotter than when soldering them on, I had doubts about letting too much heat near my injectors. They were, after all, confections of little bits of brass and two sorts of solder. Therefore, the whole job had to be achieved with the injectors still attached to the boiler feed water pipe and the cab step.
As this whole injector process had been a bit of a struggle, I was pleasantly surprised when this last job proved relatively simple to do. The existing steam and water feed pipes (actually 0.7mm rod) were cut off and filed flush with the end of the injector. It wasn’t too hard to centre a drill on the remains of the rod and drill down it. If anything, once I’d got the drill started in the right place it seemed to want to follow the rod. I wasn’t entirely surprised when the hole went into the original casting, as cast brass is quite hard, but it was a relief when the drill did the same into my extension, made of brass scrap, brass tube and solder. As pointed out on the Forum recently, its quite hard to get solder to flow very far down a hole, and this was proved to have been true, which helped. The picture shows the modified injector. The trouble with blowing up pictures this size is that it highlights any solder residue, there is an advantage to working in NS I think. It also shows faults that aren’t immediately apparent when viewed normal size, like the slight angle on the top cab step. Piping up
Next I needed to attach the necessary pipework to the chassis. I am allergic to soldering close to wheels with steal tyres given the tendency of the liquid flux to get everywhere. So the first job was to strip down the chassis. One of the things that makes me favour CSBs is that they do allow the wheels to drop out (relatively) easily, and I now wouldn’t consider trapping wheels in a chassis. My life seems full of occasions like this when the ability to dis-assemble the chassis becomes desirable. I think I have noted a tendency for those who build locos for others to consider drop out wheels an unnecessary complexity. I suppose that all that extra experience should ensure they get everything right first time and hence never need to back track the way I do. However, I do wonder if the fact that they say an early goodbye to most of their creations also plays a part.
So off came the removable brake gear (see Part 6a - Removable Brake Gear
). Then, having first marked the circumference of the wheels on the frames so I’m sure the pipes will be clear of the wheels even when the springs are fully compressed, out came the CSB wires and out dropped the wheels gearbox and motor.
The top edge of the chassis was notched to locate the pipes which were first bent to approximately the right shape. They have to pass from the injector body, below the sand boxes, in front of the sand pipe and up to the level of the top of the frames before they get to the driving wheel. Now out of view they were bent at right angles to pass through that notch in the frames, and at right angles again and down a bit so they run on top of the nearby chassis spacer. They were soldered one at a time to the frame spacer and into the frame notch, then adjusted so they will slide into the hole in the injector. The picture shows that one didn’t quite make it into the notch, but as it is firmly attached and the error is hidden up inside the body I couldn’t be bothered to do it again, or photograph the other side which was done properly. .
What I thought would be the final question was, how easy was it going to be to get all four bits of wire to align nicely with the 4 holes in the injectors, so the chassis and the body would assemble easily. Being well supported these wires end up quite rigid, even though they became 0.6mm wire as the 0.7 stuff I used to start with just looked a bit too big. So long as each rod had a rounded end, adjusting them so that all four fitted into the injectors simultaneously proved easier than expected, and their rigidity seems to ensure they stay adjusted. If for any reason they are not mating as they should the chassis simply refuses to go back the last couple of millimetres so there is no danger of miss assembly. The next photo shows the chassis before and after fitting to the body, just to prove it really does. Last steps
Having implemented my injector solution, it was just a question of reassembling the chassis and doing one more check that everything still went together as it should. Of course it didn’t. Having had the fates on my side for once, normal service was now resumed. The problem being that because the chassis has to be placed a little further forward before it could be slid in place, the clearances at the other end were reduced and I could no longer get the motor plus power leads through the boiler cut-out. Modifying these leads so they left the motor sideways rather than backward sorted the problem. Once that was done all was well. I did try and take a picture showing all the pipework in place on the fully assembled loco, but I have to admit the only people who will notice those extra pipes are going to have be looking at it from an unusual angle. Hay Ho.
Next time we’ll have a go at the Westinghouse pumps.An aside on small drills
Most all of the holes in my models I drill by hand. Almost inevitably I start by using my favourite 0.5mm drill, as this is the smallest size drill I can reliably use in a pin chuck without breaking it too often, and if the hole proves not to be in quite the right place you can always adjust it a bit if it needs to be bigger. If I ever considered getting machine tools for my work bench I would start with a drill press, but I continue to manage without one, and it wouldn’t have helped drilling those injectors anyway. The 0.5mm drills do break occasionally but that just means the one I’m using will be relatively new and sharp. I buy them in lots of 10.
Once I have a .5mm hole, if it needs to be bigger I normally open it out with a a five sided taper broach. A set of six of these in gradually increasing sizes, was one of my best ever tool purchase. They used to be unusual tools available in one set of sizes only, but the word seems to have spread as Eileen carries quite a range of these now
. My original set had metal handles and all but the finest have lasted well. My current crop, brought to replace the broken small one, have plastic handles which tend to brake off. Milleput makes a workable replacement, and they still do the job. The finest available set goes down to 0.4mm which is the one that will break if you try to hard, and the one you need if you always start with a 0.5mm hole.
Broaches don’t help with blind holes of course, as those in the injectors were. For these I keep a set of drills in 0.05 /0.1mm increasing sizes. I don’t often use these and haven’t broken them but over time they have been getting blunt and are hard work to start a new hole with. They are fine for opening up existing holes a step at a time just so long as you don’t try and step the size up too much. RC 47725