Third Floor

At this level are most of the controls and adjustments for the mill. The cranked handle below the beam operates the mechanism for engaging the stone nut with the great spur wheel to drive the millstones on the floor above.

The butterfly handle is for the tentering gear, which sets the gap between the millstones when milling.

The lay shaft meshing with the great spur wheel operates a belt drive to work the wire machine on the floor below. Note the teeth of pear wood on the great spur wheel. This is to avoid metal-to-metal contact: to achieve quiet running of the gear wheels, to reduce any risk of sparks that would be a significant fire risk in the mill, and to prevent wear or breakage of the gear wheels that would be very expensive to replace. When a wooden tooth is worn out it is a simple matter to shape and fit a new one. Fruit wood, if available, is normally used for the wooden teeth, but beech wood is also satisfactory, as is hornbeam Above the ladder from the floor below is the governor. This turns as the sails turn, and as its speed of rotation increases its lead ball weights rise and the steelyard lifts. This lowers the upper millstone, which is tending to ride up on the grain as it feeds in at an increasing rate, and ensures thorough grinding at all speeds. When the governor is rotating at high speed its weights will be as far out as they can be - hence the expression “going balls out”.

On the wall is the in-use twist peg, hand forged from wrought iron probably in the 1820s. A twist peg is used with a crook string to adjust up or down the front of the shoe mounted on top of the millstones on the floor above. The shoe controls the rate at which grain is fed into the stones and thus the volume and texture of flour being produced. Each of the original three pairs of stones would have had its own twist peg, probably mounted for ease of adjustment, as this is, on the wall adjacent to the appropriate flour spout. The twist peg of the pair of stones awaiting restoration on the ground floor is on display on the wall nearby.

Outside the doors on the reefing stage is a chain for operating the striking gear, that adjusts the angle of the shutters on the sails to vary the driving power of the sails. Quainton Mill is fitted with Patent Sails, the latest thing in the 1830s! Shutters are fitted down each side of each sail and are adjusted by the chain: to catch the wind to turn the sails, or to spill the wind and thus to slow or stop them. Once the shutters have been adjusted a heavy weight is hung on the chain. If the wind increases significantly, the pressure on the shutters overcomes the weight on the chain and the shutters will open to limit the speed of the sails; when the wind eases, the weight on the chain will bring the shutters back to their previous setting. In the former case this is a safety feature that gives the miller time to re-adjust the setting of the shutters to suit the higher wind speed.

Also on the stage is the brake rope that operates a steel band around the brakewheel on the sixth floor to prevent the sails turning when they are not in use.

On the wall is an original shovel in use in the mill before 1890 when the mill stopped operating. It was possibly used to move grain, but more likely to top up flour sacks.

Also on the wall is the frame of a shutter from the last remaining original sail that was taken down when restoration of the mill started in 1974. The shutter is made of wood, mortised and tenoned, and was one of a total of 168 shutters fitted to the four sails. The original shutters were covered with canvas attached by copper nails, and painted with white lead to preserve them. This frame is complete with its original fittings, ie its pivot and crank arm. Beside it is a modern reproduction made in the 1980s and in use from 1992 to 1999. An example of the shutters currently fitted is also on display: for long life it is made of galvanized steel covered with glass fibre sheet fixed with stainless steel pop rivets.