Watermill Machinery



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Blickling watermill pit wheel

Breastshot wheel
Most wheels in Norfolk are of this type

Overshot wheel Undershot wheel
Very few of this type in Norfolk due to the flatter terrain
Very few of this type in Norfolk

Basic machinery configuration
Basic machinery configuration


Worthing watermill gearing system
Worthing watermill gearing system
Worthing's gearing system was of the traditional style. The iron waterwheel, manufactured by Hetherington & Parker of Alton, was installed in 1876 as a replacement of the earler wheel. The bevelled pitwheel (bottom centre) drove an an iron wallower mounted at the foot of the vertical shaft. Above the wallower can be seen the great spur wheel (centre) of timber 'compass arm' construction, supplying power to two pairs of millstones through wooden pinions, or stone nuts mounted on iron spindles. These are supported on timber bridge trees (left centre), tentering being effected by handscreens. Near the top of the mainshaft is a wooden crown wheel and a lay shaft (top left) from which the secondary machinery of the mill was driven by belting. Above the main shaft is the vertical bollard of the sack hoist (top centre) driven by an iron clutch and suspended from a heavy balance beam.

Worthing watermill wallower and pit wheel
Worthing watermill wallower and pit wheel

Watermill Operation
Grain would arrive at the mill by horse and cart in sacks from the surrounding farms or the local estate. In dry summer harvest weather, carts were often stood in the water to allow the dry wooden wheels to tighten by swelling as they got wet. Mills built on navigable rivers also had a lucum built over the waterway to make use of wherries or other cargo craft.

The sacks of grain had to be taken up to the top floor and this was done by the "sack-hoist". Its chain was lowered from the lucum that projected out from the top of the mill. The sack hoist was operated by a series of pulleys and gears powered by the waterwheel.

Once at the top, the grain was emptied into either a "hopper" or a "bin". The bins (which have not been rebuilt) were used for storage and the hoppers (on the second floor) for feeding the grain to the millstones. The grain fell through chutes from the hopper into a smaller hopper on top of the stones (on the first floor) from where it would be guided into the centre of the stones by the "slipper." a moveable wooden chute. The slipper was agitated constantly to ensure a smooth flow of grain into the stones. This was done by the "damsel" (the four-armed shaft projecting up from the centre of the stone)- so called because of the constant chattering it made against the slipper!

Many mills had an arrangement whereby the front doors opened on two levels. The carter unloaded sacks from the top of the cart straight into the first floor of the mill and the cart became emptier, the lower sacks were then unloaded into the ground floor.

Norfolk mills usually had between two and five pairs of stones, which were encased in wooden "tuns". Stones were of two types, each for a different application. Derbyshire Peak grit stones wore down fairly quickly and were only fit for grinding animal feed as they left stone dust in the ground product. French burr stones were the best quality and were almost exclusively used for grinding wheat into flour because they contained crystals of very hard quartz. These crystals created sharp grinding edges that did not chip into the flour and the stones needed less frequent sharpening ("dressing"). French burr stones came from only one quarry just outside Paris and were only found in small pieces - none big enough to make a complete millstone - so each stone was made of several skilfully shaped pieces held together with plaster of Paris and an iron ring heat-shrunk around the outside of the stone.

Each of the stones is divided into sections called "harps". The harps have a complex grinding face cut into them consisting of "lands" (the raised sections) and "furrows" (the grooves) which had to be dressed regularly using a "mill-bill" and a good eye! Once the lands were properly flattened during the dressing process. they had to be "stitched". This required up to 12 fine lines per inch to give the best grinding surface for white flour.

When the stones were together as a pair they had to be perfectly balanced, perfectly level, and precisely the right distance apart - the thickness of a piece of brown paper at the centre of the stone and of a piece of tissue paper at the circumference. This gap was adjusted by a process called "tentering;" the top stone could be lifted on the "spindle" by a turn-screw on the ground floor.

Only the top stone ("runner-stone") rotates in any pair, with the "bedstone" fixed to the floor. The runner-stone is balanced above the bedstone, hanging on the "mace" (or "rynd") which is supported on the spindle. When the grain falls into the centre of the runner-stone it is forced outwards by the pattern on the surface of the stones and the action of centrifugal force. It is crushed between the lands and falls from the edge of the stone as flour. The flour passes down a chute where it can be bagged on the ground floor as 100% wholemeal flour.

White flour is produced by a machine called a wire-machine or "bolter". A series of sieves, made from finer and finer mesh are used to separate the 100% flour into bran, semolina, and white flour.

All the power for the mill stones and auxiliary machinery was provided by the waterwheel. There are three types of waterwheel, overshot, breastshot and undershot. An overshot wheel is powered by the weight of the water falling over the top of the wheel into buckets. With a breastshot wheel, the water enters the buckets level with the axle and the wheel produces only about one third of the power of an overshot wheel. The third type of waterwheel is undershot, where the water passes under the wheel; it is the force of the water hitting the paddles that turns the wheel rather than the weight of water in buckets. The majority of mills in Norfolk are either breastshot or undershot, mainly because the Norfolk terrain is no more than undulating and does not provide the high head of water required by an overshot wheel.

An overshot wheel needs a head of water that can only be provided by artificially raising a river. This would require the building of a "leat" the diversion of the river along the side of a valley, until a sufficient height of water had been reached to work the waterwheel. This was a huge feat of engineering considering the mass of soil used to construct the river banks and the similar mass of clay and chalk used to waterproof the bed of the river; remarkably built by hand. The water was built up and stored by closing the two sluices to stop the water flowing downstream. The water would fill the "launder" (or "pentrough") above the wheel which could then be opened to turn the machinery. Alternatively, if the river filled too much the sluices could be opened to allow the water downstream without turning the wheel.

A waterwheel rotates at about 10 revolutions per minute (r.p.m.) and the power is then transmitted through the wheel-shaft to the "pit-wheel" in the hurst frame. The pit-wheel drives a smaller "wallower" which in turn drives through the "crown-wheel" and "pinion", along the main horizontal lay-shaft to the "stone-nuts." Each stone-nut is attached to a stone "spindle" which drives the runner stone. By this stage the gears have increased the speed of revolution from 10 r.p.m. at the wheel to about 120 r.p.m. at the runner-stone.
With thanks to Redbournbury Mill - see Links page



Pippa Miller's drawing of a typical
Pippa Miller's drawing of a typical
Norfolk watermill


Letheringsett watermill's internal layout drawn by Barré Funnell
Letheringsett watermill's internal layout drawn by Barré Funnell


Aylsham mill's waterwheel
Aylsham mill's waterwheel


Letheringsett's water and diesel gearing drawn by Barré Funnell
Letheringsett's water and diesel gearing drawn by Barré Funnell


The Decline Of Village Mills
Until the mid-l9th century, many villages had wind or watermills to grind flour for the community. Before Henry VIII's dissolution of the monasteries in the mid-fifteenth century, most mills were owned either by the Church or by the Lord of the Manor. Milling rights were jealously guarded, and villagers would have been allowed to grind corn only at their landlord's mill. The law at that time required flour to be ground only at your Lord's mill - known as his "Right of Soke". The miller charged up to 10% of the grain, and the landlord frequently took a further cut.

At that time bread made with flour from English wheat was very different to that which we know today; it was very much heavier and little risen. The best milling wheat would later come from America where, because of the climate, the grain was harder and produced a stronger flour (containing a higher proportion of gluten).

After the repeal of the corn laws in 1846, plentiful supplies of American wheat became available. This gave a significant advantage to mills based near the major seaports. At about the same time, a more efficient milling process was invented in Germany; in this the grain was crushed between two steel rollers, rather than ground between millstones.

By the mid to late nineteenth century, many of the old watermills and even windmills were adding steam, gas or oil engines in an attempt to compete with their modern counterparts. They could not survive however against this early form of mass production and by the beginning of the twentieth century most were reduced to the grist milling of animal foodstuffs.
With thanks to Redbournbury Mill - see Links page


If you have any memories, anecdotes or photos please let us know and we may be able to use them to update the site. By all means telephone 01263 713658 or .

 
Copyright © Jonathan Neville 2003

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