The older water wheel, installed in about 1848 (Ref 2), was a large overshot wheel situated under the current Towcester Mill Brewery tap room (formerly the reception area). It was roughly 9 feet in diameter, and 10 feet wide. Only the horizontal shaft, and a fairly small pitwheel remain. The shaft has signs of where three sets of spokes joined it to form the structure of the wheel, one at each end and one in the centre. It was an overshot wheel, which was relatively efficient even in simple form.
It was replaced in 1895 by a more efficient turbine. This was a 20 inch type 7 "British Empire" turbine, manufactured by J.J.Armfield in Ringwood, Hants. The size refers to the diameter of the turbine rotor. It is a double horizontal type, with a double rotor and a vertical shaft. The water inlet is controlled via "top and bottom hatches" behind the turbine, which feed the lower and upper sections of the rotor respectively - yes I do mean that they are swapped - this is because the control gear (left hand photograph) should be rotated by 180 degrees. We think that it was installed in about 1895, but are unsure when it ceased to operate.
The vertical drive shaft rests on bearings made of Lignum Vitae, an extremely dense wood, also used as propshaft bearings on warships. This shaft drives a horizontal shaft on the floor above via a dog clutch and bevel gears shown in the middle photograph. No machinery remains, but a large pulley wheel now turns on the outside of the building. This once allowed the mill to be driven by a steam engine, before it started a serious fire in 1911, and later by a large electric motor. The maximum power output with the 9 foot head of water would have been 12 Horse Power (9kW) and the cost when installed was £85.
The machine in the other photograph is labelled "G.Groom, Millwright, Eastcote".