Knag Mill

Facts

Bone cruncher at Kongeåen

By Lise Andersen, Museumsinspektør, mag.art. (17 stories)

Knag Mill was built in about 1780 by the Kongeåen river near Rødding. In the Middle Ages, this was the site of a watermill called Gammelvad but it was ransacked in the 17th century during the wars with Sweden. Knag Mill has an undershot wheel measuring 4.5 metres tall. It was originally a grain mill. But in about 1830, it was converted to produce bonemeal. The bones were crushed under large stamps that were raised and lowered by a camshaft. In the mid-1850s, Knag Mill once more became a grain mill. The Prussian state owned the mill during the time before South Jutland's reunification with Denmark in 1920 and it continued to work until about 1950.

Partly a public place

Selected entry

Big wheels keep on turning - one way or another

Story written by Lise Andersen

Time / Periode 1780

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The oldest watermills were built like Knag Mill. The water was channelled in at the bottom of the waterwheel, which is called an undershot wheel. This pushed the blades of the wheel round in the direction of the current. In about 1430, it was discovered that, with a small dam in front of the wheel, the effect from both the current of water and the water's weight on the paddles is greater. The dams grew larger and larger over the years. The model's breast shot wheel also turns in the direction of the current. The renaissance overshot wheel is far more efficient. The water is channelled into a chute up above the wheel before it falls down and its weight sets the paddles on the wheel in motion. This turns the overshot wheel in the opposite direction to the current. The wheel needs to be mounted high so that the backwater does not disturb the direction of the flow when it splashes off and flows away from the wheel.