Three-Shaft Geared Churn: Fans Above, Screw-Form Beaters Below, One Crank

"I then divide the circumference of the bottom into three equal parts, which forms an equilateral triangle. I then find the center of its sides, at which I place the boxes in which the feet of the shafts stand. I make the boxes of lead or zinc."

Print the plate (/uploads/blueprints/three-shaft-geared-churn-plate.stl), the centre gear with its crank arm (/uploads/blueprints/three-shaft-geared-churn-centre-gear.stl), three pinions (/uploads/blueprints/three-shaft-geared-churn-pinion.stl), three fans (/uploads/blueprints/three-shaft-geared-churn-fan.stl), fifteen beaters (/uploads/blueprints/three-shaft-geared-churn-beater.stl) and three foot boxes (/uploads/blueprints/three-shaft-geared-churn-foot.stl). Print in PLA at 0.2 mm layers, 30 % infill, 4 walls; wash before first use.

Mark three points 64 mm from the centre of a food-grade bucket's floor, 120° apart, and bed a foot box at each in silicone. Screw two pine battens across the rim and screw the plate on them, its three holes over the feet.

Cut three 10 mm square hardwood shafts from the foot boxes to 40 mm above the plate. Slide five beaters on each, turned a fifth of a turn apart, then a fan near the top, and glue them. Stand each shaft in its foot box, drop a pinion on through the plate, and set the centre gear in the middle hole on an M8 bolt. Glue a hardwood dowel handle in the crank arm.

Let 1 litre of heavy cream stand until it reaches about 15 °C, checked with the thermometer, and pour it in. Turn the crank steadily and 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.

**Milo B. Hough** of Dover, Cuyahoga County, Ohio, received US 1,072, dated 21 January 1839. He made his churn about fourteen inches across at the bottom, twelve at the top and twenty-six inches in the staves; the shafts about one and a half inches through, bored with three-quarter-inch holes two and a half inches apart for the beaters; a mortise near the top for the fans; and pinions about two and a half inches across within one and a half inches of the top. The frame's feet sit in loop holes in the hoops to keep it steady, and the lid is jointed at the shafts so it can be taken out. **Honest limits.** A bucket and printed parts stand in for his staved churn. Our crank turns the centre wheel directly, without his bevel stage. FDM prints hold food in their layer lines, so wash well and replace when worn. Your times and weights are the result.