December 2004 Progress report
article by: John McMillan
We have concentrated on just a few projects over the past three
months or so, but have seen a lot of effort and considerable
progress achieved on each.
The most obvious progress has been made on the fire-box
cladding. Of all the "big shiny bits" on the locomotive, these are
certainly among the largest, and the whole of the fire-box has been
clad in sheet steel. Combined with the almost-finished cab, the
back end of the loco is really beginning to look complete, and is a
definite indication to the world that we mean to see this
long-running restoration project through to a successful
conclusion.
Getting to this point, however, has involved a good deal of
painstaking work. On the driver's side, some final adjustment had
to be made to the steel crinoline strips that support the cladding,
and an old vacuum exhaust pipe (the original, retained as a pattern
for a new one), plus the reverser shaft were temporarily fitted in
place to check the alignment. Once we were happy, the cladding
sheets could be fitted.
The sheets on the fireman's side are of fairly straightforward
design, but those on the driver's side are far more complex, having
tapering indents to accommodate the vacuum exhaust pipe and the
reverser shaft. Both the sides and the crown sheets also required
holes to be cut for access to the boiler wash-out plugs.Ensuring
that the sheets were being cut in the right places to locate the
plugs behind them, required the development of a special technique
which has worked well (so far!).
The next interesting piece will be the tapering cover for the
manifold main steam pipe, which runs along the centre line of the
fire-box crown. After that it gets even more interesting; the
pieces covering the fire box throat, where it joins the boiler
barrel, can best be described as fiendish, and the barrel is clad
with a series of sheets, each twenty one feet long! Fortunately,
our sheet metal worker has done similar work on Bulleid Pacifics
before, so he is aware of the problems, and in addition, we have
received welcome co-operation from the Group overhauling 35028,
"Clan Line". They are replacing much of the time-expired B.R.
cladding on their loco, and we have visited them for advice and to
see examples of the parts we are trying to make.
Elsewhere on the locomotive, final adjustments have been made to
the injector control rods, and the universal joints have been
permanently pinned in place. End-stops on the travel of the control
wheels have been set to restrict the opening of the steam and water
valves to prescribed settings. The troublesome water valve, which
was very stiff, has been reworked but is still too stiff for our
liking, and will require revisiting in the future, to try and free
up the movement a little.
We have been able to complete various machining jobs at
Toddington this quarter, thanks to the large number of machine
tools available. These belong to various other restoration groups
as well as ourselves, but the good level of co-operation among the
groups gives access to a wide range of tools that would otherwise
be beyond the resources of any individual group. The well-equipped
workshop benefits everybody in saving a great deal of money through
having to have parts machined commercially, and enabling quality
control to be maintained 'in-house'.
Parts receiving machine shop attention have included the pair of
clack valves. These non-return valves supply cold water to the
boiler from the injectors, and will require steam-tight mating
faces where they attach to the boiler. Machining these involved the
making of a "female" nut, which in turn required the making of a
"male" spanner. Well, it would, wouldn't it?
Another major item now completed is the main steam manifold
shut-off valve, whose hand-wheel is located on the front of the
firebox on the left hand side of a Bulleid Pacific. The valve
supplies steam to all the auxiliary system controls in the cab, and
is an important safety feature of the locomotive. If a serious
steam leak develops in the cab, possibly causing the crew to
evacuate, the steam supply can be shut off safely from outside. Our
valve is original, and required a full overhaul. Machining is
complete, but the faces still need to be scraped flat to achieve
steam-tight joints. As the complete assembly weighs about three
hundredweight (160kg), lifting it up and down between trial-fits is
going to be a lot of fun!