Part 8: Making a new cylinder—April 2001
New left hand cylinder
The pattern making work for the new cylinder/s is expected to be completed during the first week of May.
The cylinder will be cast on its end, thus the sand mould made from the end of cylinder core box will become the base upon which all will be built. There is in fact no pattern item that represents the actual outside shape of the cylinder in its entirety. Basically, the process is to have shaped boxes in which blocks will be made from self setting foundry sand. This will create a set of strange shaped lumps of sandstone which will then be assembled, like a 3D jigsaw puzzle, to form the outside shape of the cylinder as a hollow space between them.
A similar process will be employed to produce the sand pieces (called cores) that create the holes through the casting that will be the main bores, and the passages for the steam to go in and out through. These are progressively fitted into the hollow described above as it is all assembled. Once the whole lot is assembled, it will be surrounded by dry sand to hold it together ready for the metal pouring business.
Boiler work update
The boiler has finally reached the point where there is no more metal to be removed. Metal is in fact being reattached, with various corroded areas being built up by layers of electric arc welding in a process called "pad welding". New boiler plate has arrived, and the process of preparing it for insertion is about to begin. The welding procedure test welds have been done, and all that remains before we can go ahead here is completion of the mechanical tests to qualify (and thereby approve) the repair processes.
The many replacement parts such as new stays and studs are in the process of being made. The next major step is to complete the steel former to form the flange for the portion of tube plate being replaced (damage shown in Part 5), and to then beat a 12mm piece of boiler plate to the required shape. Fortunately winter is upon us, as this will be a hot and muscle toning exercise!
Cab, frames etc.
The cab is now almost complete, as is the smokebox. Design and drawing work is almost complete for the new main frame assembly, and assembly of this could begin in the next couple of weeks. The trailing driving wheel set has been re-assebled with its new axle, and setting up for reboring the crank pin holes is scheduled to happen in early May.