Tuesday, 19 November 2013

The millwrights return to Nether Alderley Mill

We have closed the mill for the season now and will re-open in the spring. The National Trust has taken the opportunity to invite the Norfolk Millwrights, who did the recent restoration work on the mill machinery, to return to Nether Alderley to check on the condition of the mill after our first season milling grain, and to repair a couple of minor faults which have developed.

As ever, please click on any picture for a larger image.

My car and the Norfolk Millwright Alliance van outside the mill this morning

An autumnal view of the mill pond

Sluice manhole open as the millwrights run the mill machinery to check for faults

The sack hoist has to be checked for its ability to raise sacks of grain, and the results documented, like a crane or lift. Not something you'd expect to have to do in a 17th century mill.

The grain hopper has been removed, and here the ropes connecting the shoe to its wooden 'spring' and for shoe-height control are removed. After that the 'horse' (the wooden frame that supports the hopper) and the 'furniture' (the shroud around the mill stones) can be removed.

When the furniture was removed an unexpected sight greeted us. The 'sweeper' (which should be attached to the runner stone and sweeps the meal to fall down the chute as it emerges from between the stones) had become detached. Flour (meal) had therefore built up inside the furniture and had to be removed before work could proceed. It filled three large sacks and a couple of vacuum cleaners!

The millwrights attach fabric straps to the runner (upper) stone

Two block & tackles were used to lift the runner stone off its support shaft, and thus expose the bed stone (the lower of the two mill stones, which does not rotate)

Once the stones were separated we were pleased to discover that the milling surfaces were in excellent condition. The mace can be seen in the centre of the bed stone atop the drive shaft which comes up from the hurst frame below. The upper, or runner, stone rests on this and is driven by it as the slots in the mace engage with the metal rind in the centre of the runner stone.

A view down the 'eye' of the runner stone, showing the rind, and the mace beneath the runner stone. The square drive atop the rind drives the damsel which agitates the shoe allowing grain to fall into the 'eye'.

Here the millwrights have removed the metal cover from the bed stone centre bearing with its hessian gaskets, and extracted one of three bronze bearing pieces (in the millwright's hand)

Here's a close up of the bearing piece. It is tapered top to bottom and front to back, so as the three bearing pieces wear they take up any slack automatically. In between the bearing pieces are wads of grease-impregnated hessian to provide lubrication. The bearing piece is resting on the metal sealing collar in this picture. Once the hessian has been re-greased, this collar will be re-fitted with new hessian gaskets to keep flour dust out of the bearing.

A bronze bearing piece, hessian grease pad, and the sealing collar

Nice autumn view at the back of the mill

Finally, the bearing having been re-greased and the stones' faces cleaned, the runner stone is lowered back onto the mace


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