Stage 3 components
Whether or not the inspector will wish to conduct a hydraulic test I decided to carry out a hydraulic boiler test for my own satisfaction. First step today was to make plugs to fit the various screwed holes in the boiler. I already had 1/4" x 40 and 3/16"x40 plugs as I use these when testing 16mm scale locomotives. In addition I needed 5/16"x32 and 1/2"x26. As I had no dies to make these I spent some time converting the lathe to imperial. (I had converted the lathe to metric soon after purchase but had kept the imperial parts for just such an occasion.) It took about an hour to take out and replace the metric leadscrew, split nuts and thread indicator. By the time I had finished screw cutting the new plugs it was time to break for lunch.
During the afternoon I connected up my test pump and pressure gauge, filled the boiler with water and pumped up to 1 1/2 times working pressure (that is to 150 psi). There was no problem with the boiler although some of the old 'O' rings on my boiler plugs gave trouble initially. After holding pressure for around 10 minutes the water pipe blew off the pump outlet. I normally test boilers with working pressure of 40 psi so have not had to work with this high a pressure before other than when testing gas tanks.
Later in the day, pushing the chassis along by hand revealed another tight spot which I mistakenly thought might be something to do with the right hand trunk guide/bottom cylinder cover. Then followed an interesting exercise in removing this from the engine without removing the engine from the frames. To do this I needed a very long Allen key. I cut a length of hex rod off a spare key and made a long handle using a 4mm socket head bolt screwed in to a piece of steel rod. It worked ok but having dismantled things I found the tight spot was elsewhere. The eccentric straps on one side were rubbing against each another in one postion on every revolution. I eased this slightly but should not really have bothered as any tighthness would be bound to disapear once the engine is running.
After reassembly I left the engine running on air for 20 minutes or so in each direction whilst doing other things.
The boiler inspector has examined the boiler and test certificate. New regulations have been published since the boiler was built. For instance new boilers should now have CE marking. He has accepted the manufacturers hydraulic test and will undertake a steam test once the engine has been completed.
The boiler is retained in place by the steel sheet forming the cladding.
The cladding could then be drilled to take the boiler mounting brackets. I think I may have slipped up here as one of the brackets overlaps a hole in the footplate. I need to check what fits in this hole to see if I need to move that bracket. The next step will be to drill holes in the frame to bolt the brackets down.
Having got this far I could not resist trying the tank and bunker in place
At last it begins to look something like the real engine.
The next step was to fit the firebox door. Maxitrak supply a door already bent to shape with a strip of brass to make a spring catch. I felt a traditional latch arrangement would be easier to open and close, particularly when hot. Ideally I would like to be able to flick the door open with a loaded coal shovel.
I have used a latch on a couple of 16mm locomotives so scaled it up by using 1/16" steel rather than 22 swg brass. the end result is quite pleasing.
Firebox door with homemade latch
Making and fitting the latch took longer than I had thought and so painting the cladding will have to wait for another day.
Lagging wrapped around boiler
The next step defeated me. I got the cladding in place but could not compress the lagging sufficiently to get the tow ends of the cladding to join up. Maybe with a few more straps or someone to help I could have managed.
Compressing the lagging defeated my efforts
Maxitrak suggest the use of cork sheet as an alternative. I had some spare cork floor tiles so tried this instead. I found this a lot easier.
Alternative lagging from 1/8" cork tiles
With the lagging closed I could now turn my attention to the smokebox lid. I opened out the holes in the lid so it would fit over the retaining pins and checked that the nuts provided would fit.
I could then try the boiler in the frames again. I filed away clearance for the check valve bushes so the boiler can push down into place with very little manouvering. I found I needed to ease the hole in the boiler and cladding where the blast pipe goes to the engine unit. I spent some time ensuring that the blast pipe aperture lined up with the centre of the chimney. After opening out the mounting holes in the frames to 3.5 mm I was able to check that I could fit the mounting bolts and nuts. Using slightly longer bolts than those supplied made this task a little easier. I think these bolts came from a 1950s black and white TV set I dismantled around 30 years ago.
The last task of the day was to spray the cladding and smokebox lid with high temperature black paint. I used three coats of paint sprayed with an external feed airbrush. Between coats the parts were cooked gently in the oven for half and hour at 200 degres Farenheit.
Boiler and smokebox lid after painting
In between coats of paint I took a break and ran a much smaller DeWinton round the garden
Stage 3 complete
