Chaloner Stage 3
- 22nd May - next comes stage 3.
This consists of the boiler, lagging, chimney and fastenings. Before
fitting the lagging I am going to take the boiler to the club
boiler inspector along with the hydraulic test certificate which
can be seen in the photo below.
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.
- 24th May
- The boiler aroused a fair bit of interest and discussion at the club
as this will be the first copper welded boiler to have been brought
there for testing.
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.
- 25th May
- The first task today was to open out the pre-cut holes in the
cladding sheet to fit as snugly as possible around the various boiler
bushes. Once this was done the boiler could be tried in place in the
frames. The circular hole in the frame needed opening up a touch. This
took quite a lot of effort but eventually I was able to nudge the
boiler into place. The level of the boiler is governed by the blast
pipe position. As I still had the lathe set up for screwcutting I
exended the thread cut on the end of the blast pipe in case I needed to
adjust its length to ensure it will be central under the chimney. With
the boiler raised up on blocks the blast pipe screwed straight into the
engine. I could now mark out the position of the mounting
brackets.
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.
- 26th May
- I had intended to finish drilling and filing the boiler cladding
today and then to apply a coat of heatproof paint. I did the
drilling for the smokebox retainers and also filed away the notches at
the top of the cladding to ensure the regulator and main steam pipe
would fit. To make it easier to adjust the position of the blast pipe I
cut a screwdriver slot in the end. I will need to ensure the blast pipe
orifice lines up with the centre of the chimney when the boiler is
being fixed in postion for good.
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.
- 27th May
- Cleaned up the inside of the cladding sheet and gave it a coat of
primer. I still need to paint the outside but will probably do this
after putting the lagging in place.
- 28th May - Drilled the holes in the footpate for the boiler mounting brackets.
- 29th May
- The lagging supplied is ceramic fibre around 3/8" thick. This needs
to compress down to 1/8" to fit inside the cladding. It was a
simple task to cut the lagging to size and hold in place with masking
tape. The retaining pins for the smokebox lid were held in place with
more masking tape.
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

- 30th
May - I dropped the painted boiler into position and fitted the brass
band around the boiler. Then outside it went for a photo with Idris the
16mm scale DeWinton alongside.
Stage 3 complete

On to stage 4
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