In beautiful sunshine last Friday we left London and headed along the M4 to Berkshire to visit millwright Owlsworth IJP and check out progress on Brixton Windmill’s sails. Just outside Henley, red kites were soaring over the ploughed fields, and Owen, our photographer, started lamenting that he hadn’t set up the telephoto lens on his camera.
We were greeted by Paul Sellwood as we arrived at the converted farmhouse and walked over to see our newly restored 30-foot sails.
The photo above shows the slight difference in angle of the sail between one end and the other. This is so that when the sail is turning, the angle at which each part of the sail meets the wind is the same. Because the tip of the sail has to move further than the parts of the sail near the centre, the angle has to be altered along the length of the sail so that the whole sail meets the wind at the same angle – this results in the slight “twist” you can see.
To give extra stability and strength, Owlsworth will also be adding stock clamps (see left).
The patent sails now have shutters made of softwood frames and canvas. While we were there, engineer Alan Smith arrived with the unique sail control mechanism that he and Paul have devised to open and close the shutters on the spring sails. Essentially, while standing on the ground, you attach a handle to a long screw thread near the tip of the sail. This in turn is connected to a rod that pulls the shutters open or closed, depending on the direction in which it moves. If you wind the handle one way, the shutters will be pushed open; if you wind it the other, the shutters will close. A stop block prevents you from winding any further once the shutters are closed, and there is a locking handle to clamp the screw thread (and hence the shutters) in position.
The pull rod is connected to an elliptical leaf spring at the other end of the sail near the poll end to take up the tension in gusty conditions. Each of the two spring sails will have its own mechanism.
The two common sails have also been restored, but we are unlikely to use canvas on these, as it requires someone to climb up and tie it on, which would be too dangerous!
Paul says that the sails will need to be rotated regularly to prevent water from settling, which could lead to rot. If maintained properly, they should last for 10-12 years.
The provender millstones have been dressed (grooves sharpened so that they can grind properly). It took Paul about two days to complete the quarter dress pattern (below).
The hopper that sits above the stones has been lined with zinc, and all the gears have been cleaned up and repainted.
The provender mill will be driven by a new motor, and an inverter will also be installed to ensure that the mill starts up slowly. It will be running at a speed of 100-120rpm when in full flight, so it’s best to control the rate at which it starts!
Our thanks to both Paul and Alan for a very informative visit – it’s heartening to see the care and thought that has gone into the restoration of Brixton Windmill.