How it Works
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There are two
water wheels at the mill. The working wheel is at
the north end of the mill and this can be
operated for school parties. The south wheel is made of iron and is smaller than the north wheel. The north water wheel is made of elm and cast iron. When water is let out through the bottom of the sluice gate, it fills the buckets on the wheel and the weight of the water turns it around backwards. |
This type of wheel is called an overshot wheel, as the water comes out of the sluice above the middle of the wheel. It is sometimes called a back shot wheel as it turns backwards.
Water wheels were invented 2000 years ago by the Greeks although their wheels were set horizontally rather than vertically as at Sarehole.
The water wheel is connected to the mill stones by gears. As a water wheel turns about 4 times a minute and the stones need to turn at 120 times a minute, two sets of gears are used to achieve this high speed. The wooden gears with removable teeth are true cog wheels. The cast iron gears are true gears. The iron gears speed up the motion 5 times and the wooden gears speed up the motion 6 times, giving an increase in speed of 30 times in all.
The gears turn the stones from beneath by means of a shaft which passes through the lower stone to engage with the runner stone above it.