The next job was to make and permanently insert the fitted bolts and nuts for the cylinder joint. The cylinder block was then taken off the ‘coffee table’ and turned over to stand on the floor upside down as seen in the photo. One of the extension frame blanks has been placed where it has to be fitted when after machining.
Each end of each cylinder bore 5 studs have to be fitted to reinforce the casting around the steam ports. Three of these studs are shown during manufacture – the one with the plain section to be fitted across a steam port. The ends are finished with square sections used to drive the studs into position when the squares are then cut off.
This photo. shows one cylinder end with the 5 studs in position and the ends dressed off. 3 can just be seen within the steam port and 2 between the cylinder bore and the steam chest below.
A close up view of the steam port showing the studs in position.
This photo shows one new extension frame plate on the milling machine preparatory to being set up for machining to size.
This photo shows the old extension frames which have been retained to act as patterns for the machining. The new plates will be thicker to resist cracking and/or bending when 4561 is next in service.