*Updated* Samson - Machining of reverser and pump stand completed...

*Updated* Samson – Machining of reverser and pump stand completed…

The current focus of work on Samson is centred around the cylinder block (seen in earlier posts) and the reverser/pump stand.  Here we look at some of the machining work on this component that has been undertaken…

Below: The reverser stand is an awkwardly shaped component and in order to be able to securely mount it on the milling machine, David made a pair of mahogany quarter moon sections, with machined apertures to assist in locating it on the table.  They also have drilled and bushed holes enabling the casting to be tightly bolted to them, as seen here.  The hook is on the crane, which is used to safely handle the casting during set up and prevent it being dropped from the table.

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Below: Seen here during set up, a boring head is being prepared to expand a hole, which will be internally threaded to locate the pump valve assembly.

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Below: This close up (the machine was switched off!) shows the boring head at the top, which enables the boring bar to be adjusted to increase its throw away from the centre line, thus enabling a larger bore to be created – this process being carried out in increments to ensure accuracy.

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Below: Remote control enables this view showing the boring process ‘live’.

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Below: After re-setting of the components, the pump chamber was then drilled, then bored in the same manner as seen above.  A step is evident within the bore, into which the gland locates (which in turn retains the packing), the deeper and narrower bore being that in which the pump ram operates.  The two threaded holes, also cut in the same session, will retain the studs on which the gland (a bronze casting) is secured and slides to enable re-packing of the gland.  The whole component should be completed next week, and the photographs that I’ll post then should explain the set up more clearly than words.  This casting carries the reversing lever, regulator lever, pump and pump valve assembly, so is of signifcant importance to Samson!

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Below: Meanwhile, away from our machine shop, David is also working on other components, including the expansion link, seen here in the early stages of preparation – it has been chain drilled to ease the work the milling machine has to do, and a jig will ensure the curves on inside and outside surfaces are consistent, likewise the die-block which will be machined at the same time to ensure a precision fit.

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Below: This view shows Samson to date, with the cylinder block in the foreground.  The boiler is raised to aid fitting the smokebox door ring and door.  It sits on plastic lined cradles which will also support it under the radial arm drill when the time comes to drill the numerous mounting holes around its radius.

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Below: As promised, here are some photos taken this morning showing the whole reverser and pump unit trial assembled.  There is a considerable amount of work here and the components are now stored pending fitting to the boiler barrel shell.  Dave and Chris have now moved on to finishing the smokebox door ring.

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