Stone Floor

From High Salvington Mill Trust

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There are 2 pairs of stones driven directly by the windshaft, in a "Head and Tail" configuration.

The breast stones are of Derbyshire millstone grit, quarried as whole stones in the Peak District. These were mainly used for grinding animal feed as they tend to be more suited for larger grains, peas, beans etc. However, they are now used for milling our flour.

The tail stones are French Burr stones made of pieces of hard quartz mined near Paris, bound with iron bands, and set in plaster of Paris. They are used mainly to grind grain into meal or flour for human consumption.

Dressing the stones - is the term used for cutting the radial grooves furrows) into the grinding surface of the stones. Over time, the runner stone becomes concave which means that the main grinding action takes place nearer the edges.

At the outer edge of the stones the gap (nip) becomes very small - only a few thousandths of an inch.

The grain is fed into the eye of the top (runner) stone which rotates anti- clockwise.

The furrows are cut in a “tick” shape to allow the grain to move towards the outer edge. As the back of the “tick” is upright, the grain has to move up the slope, and the bran gets ground off by the runner stone, as it passes the ‘lands’ (the flat and highest point). For grinding, the stones rotate at between 100 and 140 rpm and must not touch, as they could spark and ignite the flour dust. Fire was the most usual cause of destruction of mills.

The flour meal is warm when it is thrown out from the stones, where it is scooped into the flour spout and falls down to the meal bins on the spout floor below.

The Brake Wheel which was made by The Friends over a period of 8 years from start to installation, is 10 feet (3 meters) in diameter, is of clasp-arm design, and wedged on to the windshaft. It is made from 3 woods: Oak for the spokes or clasp-arms; Elm for the rim or felloes; Apple for the cogs. There are 136 teeth, which are individually fitted in their own mortices and pinned at the back.

The Band Brake around the brake wheel is 30 feet (9 meters) long, and is operated by the large brake lever.

The Tail Wheel is a compass arm wheel of 8 feet (5.3 meters) diameter, with 80 cogs. The design is now rare as the spokes radiate from the windshaft. The wheel is very old and almost certainly original.

The Wire Machine is a grader driven by the tail wheel. Flour is graded and falls into 3 chutes which have sacks attached on the spout floor below. It was built by the volunteers in 1985/6 using photos of the original one.

Sack Hoists (2) can be seen above the trap doors beside the brake wheel, and in the apex of the roof. These are driven by friction drives off the tail wheel.

The hoist at the rear of the mill lifts sacks of flour from the spout floor to the bin floor, the other lifts grain from the roundhouse to the stone floor.

Output. The maximum output of meal is approximately 1 cwt (50kilos) per hour with a powerful consistent wind. However, our millers once decided to grind during a howling gale. On that occasion they produced 1 cwt in just twenty minutes. A strong gale is perhaps not a wise time to grind! Our normal grain is purchased through a local dealer and is grown in the south of England. Initially we used a mixture of Canadian and English because English grain was soft but English farms have since begun to grow harder varieties.

The wholemeal flour produced at High Salvington is unbleached and does not contain any preservatives.