Like a moth to a flame I’m drawn to the awful and predictable pun, even though the Kerr Stuart drawing refers to them as a windows. Going back in time to the 17 October 21 blog, the mechanics of the window catches were described when Bob Smith and Adam Livingston were busy making the patterns, the castings from which arrived back in time to make an appearance in the 16 February 22 entry. Norman Bond has subsequently produced the patterns for both the round and rectangular windows and the components for these have been cast too, arriving during the special Christmas of 2022 with the injectors, governor body and a box of new drills to make all those rivet holes.
Our machinist man for these little jobs, Dave Linton (who is also our little man for machining jobs) has put some considerable mental effort into working out how best to set up the various bits for machining. This is the clamp set-up used in the four jaw chuck of the lathe to turn the catches and hinges.
The hinge castings and bearings are seen here post machining. The castings with the slots are the lower hinges to the windows.
The slots allow the hinge to clamp onto the pins, to hold the window in the open position. The full assembly is shown here, with the wing nuts also machined by Dave.
Who also made all of the other brass components required to fit the hinges to the cab sides.
Like all blokes who have kept something in their shed for years, he was particularly pleased that the kitchen worktop offcut from 1999 made a wonderful mounting plate to support the round windows for machining. It is seen here mounted on a rotary table, being used to machine two castings to make them into a matching pair.
The drilling in the lower picture came first but it is hard to envisage the ingenious rotary table set-up from the drilling view. Worth capturing the moment in case you want to try this at home.
With all four castings drilled and mounted on the board Dave then put the whole set in in one of the Dean Smith & Grace lathes at Boston Lodge to skim them.
The various components, with the exception of the catches to hold the windows shut, are seen here in a dry-run assembly on the loco. It is curious that the bosses are outside the cab, requiring a slot cutting in the cab front.
Mounting the windows in this way moves the centre of the hinge pins outwards, allowing the hinges to be almost flush with the cab sheet (as shown in the drawing below).
Another minor detail that is so nice to get right, which can be seen in the photo below:
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