Inclined-Shaft Piston-Wing Churn: Loose Pistons Slide by Their Weight Through Two Turning Wings

"The wings are perforated, and through said perforations pass a system of double headed pistons a a, fitting loosely and having a reciprocating movement by the action of gravity, as the shafts rotate."

Print two bevel gears (/uploads/blueprints/inclined-shaft-piston-wing-churn-bevel-gear.stl), two wings (/uploads/blueprints/inclined-shaft-piston-wing-churn-wing.stl), with supports under their sleeves, and twelve pistons (/uploads/blueprints/inclined-shaft-piston-wing-churn-piston.stl) with twelve caps (/uploads/blueprints/inclined-shaft-piston-wing-churn-piston-cap.stl). Print in PETG at 0.2 mm layers, 30 % infill, 4 walls; wash before first use.

Push a piston through each hole of the wings and glue on its cap, so it slides freely between its two heads. Slide each wing onto a 10 mm square hardwood shaft, near its far end.

In a food-grade tub about 220 mm across, fix a pine block on the floor for the shafts' far ends. Run the two shafts down from one side, 28° apart, falling about 32°, meeting at the gears near the wall; one passes out through the wall for the crank. Set the bevel gears in mesh and glue a pine crank on.

Let the heavy cream stand until it reaches about 15 °C, checked with the thermometer. Pour in 1.5 litres. Turn the crank steadily; listen for the pistons sliding. Time until the butter comes. Pour off the buttermilk, add cold water, churn a little and pour off again until it runs clear; work in a pinch of salt and weigh the butter.

**H. N. Mackey** of Morgantown, Monongalia County, Virginia, US 17,159, 28 April 1857. He claimed the oblique wings combined with the double-headed self-acting pistons passing through them. He wrote that the pistons cut up the currents and give friction surfaces where butter starts to form. His drawing gives no sizes; ours are ours. FDM prints hold food in their layer lines, so wash well and replace when worn.