These photos and the video show progress on the milling and drilling of the main frame plates at Boro’ Foundry at Stourbridge. The main frames are set up on the large Elga Mill and the top surfaces are being machined first. The table is big enough to accommodate the 11.2m length of the main frames, however the cutting head can only move 8m. Hence the frames will be reset 3 times, once to complete the machining of the top edges, then twice more to machine the bottom edges and the horn slots. Fortunately 8m is long enough to machine all the horn slots in one setting which will ensure that their positions relative to one another are accurate which will make eventual setting of axle centres easier than with Tornado.
The leading frame extensions are simultaneously being machined on a gantry mill. The left and right hand plates are tack welded and clamped together on the machine table so that they can be machined and drilled together. The video shows the cutter returning to the start of a cut at the rear end of the upper edge of the frames and proceeding via a large cut out where the one piece cylinder block will sit. All edges of the profiled frames are being machined to remove the metal that is heat affected by the flame cutting process. Typically 0.25″ is being removed around the edges in 2.5mm deep cuts. (Apologies for mixture of imperial and metric units – the drawings are imperial, the machine metric!). After the plates are accurately set up both machines, cutting is Computer Numerically Controlled (CNC) from a .dxf drawing which in turn is derived from the Solidworks 3D model of the locomotive.
The buffer beam and small components – David Elliott
The leading frame plate extensions are milled – David Elliott
A different view of the milling in progress – David Elliott
Machining the cut-outs for the cylinder block – David Elliott
Viewed from the rear, the sheer size of the frames is apparent – David Elliott
Milling the main frames – note the tack welds holding the two together – David Elliott
The tender frames were machined at the same time as the main frames – David Elliott