The 4709 Group have published their latest update on building the tenth member of the Great Western Railway (GWR) 4700 Class No.4709.
Smokebox Saddle
Great progress is being made by Roach Precision Engineering, based in Brierley Hill, in machining the smokebox saddle and cylinder block.
Using their modern CNC machine, the team at Roach will mill with straight cuts from front to back to produce the curves required to allow the smokebox to fit correctly.
Extension Frames
Examination of the extension frames has shown some welds, carried out many years ago, have flaws which are currently be corrected.
Once this work is completed, the extension frames will be delivered to Roach, where holes in the main cylinder block can be drilled and tapped. Although the holes could be drilled based off drawings produced by Swindon Locomotives Works, the best plan is based the holes for the cylinder block off the ones on the extension frames, ensuring both fit together perfectly.
On completion of this work, the cylinder blocks can be transported to Tyseley Locomotive Works, where the team can start to build the front end of No.4907.
Pistons Valves
Four piston valve liners have been cast and are now in the process of being shipped to Roach, where they can be machined to size. This now leaves the piston heads and valves as the last items for the cylinder assembly to be cast.
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