Final Design
April 17th, 2010
  • E Pluribus Unum - One Out of Many
  • In addition to being an outgrowth of the many mills that were measured and researched for this project, the Yorktown Windmill design went through several iterations before it found it's final form. The drawings shown here show several of the design stages that the project went through.

    As you can see from the drawings, the original mill was somewhat taller and had a shaller cap than the final design. The design allowed more of the brake wheel to be housed in the second floor.

  • A Unified Design
  • As the windmill design transformed from being a fixed system to being a mobile design, it was necessary to reduce the scale to make it manageable by a team of assemblers. The second floor was compressed to be a simple machine housing and the main shaft was reduced accordingly. Because the gear system had already been constructed, it was necessary to adapt the new design to accomodate the existing components. Consequently, the cap is a bold 54 degrees - allowing the 8 foot brake wheel to fit snugly into it.

    To view an animation of how the unit is assembled, click here.

  • A Foundation for Success
  • Not terribly exotic, the foundation of the windmill is remarkably stout. It is constructed from pressure treated lumber and features doubled 2x6 floor joists that provide exceptional support with a minimum of depth. The general design allows the floor to be split into halves that are used to bind four of the first floor wall panels to create a portal unit.

    Because shrinkage is always a concern with pressure treated lumber, each of the floor boards has a batten installed beneath that will prevent weather exposure when the boards shrink as they dry.

  • The First Level
  • The first level contains the pediment, the stone cases and the hoppers. A large center brace supports the gear system that resides in the second level - providing expansive space for the miller and hios customers. Notably, all of the walls of the windmill are canted at 11 degrees to allow for the rotation of the sails.

  • The Machine Housing
  • Also called the second level, the machine housing is where the Wallower, the Great Spur Wheel and the Stone Nuts reside. It is a foreshortened structure that allows the maximum amount of wooden gears in the minimum space.

  • The Dead Curb
  • Unlike a 'Live Curb' which has cast iron wheels on which the cap rotates, a dead curb is simply a pair of greased wooden plate. Rather than using animal lard, the Yorktown Windmill's dead curb has several layers of shallac that are topped off with a coat of paste wax. Remarkably, because of the scale of the mill and the precision of the curb's fit, once the initial friction bond is broken the cap can be turned easily by one man.

  • The Cap
  • The windmill's cap is a model of simplicity and elegance. With only 16 rafters and a variety of fairing braces, the cap is more remeniscent of a ship's ribs than a building roof. The rafters are covered with 1/4" birch plywood that is pre-cut to the proper size and then bent to fit. 3 Layers deep, the plywwod sheathing has wood glue between each layer and is topped with 15# construction paper and Blue Label cedar shingles - the finest available.

  • The Machine Within
  • Finally, the building would be for nought were it not for the system of gears that transfer power from the sails to the millstones. The diagrams here show how the gears are installed within the mill.

    For additional information, please contact Walt Akers.