Spiral-Float Air-Arm Churn: A Perforated Screw Over a Breathing Wedge

"This spiral float with vertical axis answers a three fold purpose—namely for producing a vacuum—agitating the cream—and gathering the butter—the butter being churned by turning the spiral float to the right and gathered by turning it to the left."

Print the hollow shaft with its funnel and wedge-shaped arm upright, with supports (/uploads/blueprints/spiral-float-air-arm-churn-shaft-and-arm.stl), and the spiral float upright with supports (/uploads/blueprints/spiral-float-air-arm-churn-spiral-float.stl): unperforated for its first quarter, perforated beyond. Print the crank arm (/uploads/blueprints/spiral-float-air-arm-churn-crank-arm.stl). Print in PETG at 0.2 mm layers, 30 % infill, 4 walls; wash before first use.

Glue a small leather flap over the arm's outlet along its leading side, so it lifts when air blows out and closes against butter, as his spring valve. Slide the float down the shaft, its unperforated start just above the arm, and glue it. Stand the shaft's foot in a seat drilled in the centre of a food-safe box's floor.

Pass the shaft through a plywood half-lid and fix a hardwood crank to it below the funnel, keeping the funnel open. Stand a clean tin can in a corner as his tempering vessel: warm water in it to raise the cream's temperature, ice water to lower it.

Pour in 1.5 litres of heavy cream and bring it to about 15 °C with warm or ice water in the can, checked with the thermometer; then lift the can out. Turn the float slowly to the right and time until the butter comes; then turn it to the left to gather the butter at its foot. 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.

**Henry Stanton** of Richfield, Otsego County, New York, received US 6,961, dated 18 December 1849. The shaft was held by two pointed set screws so the float came out for cleaning, and turned by a small bevel wheel and a larger one on a cranked horizontal shaft on half the lid. He poured an alkali into the funnel "for correcting the acidity of the cream"; this build does not, and nothing should be added to cream for butter unless you know it is safe. He explained the result by the oxygen of the atmosphere; that is his account. He claimed the combination of the perforated spiral float with the prismatic radial arm and vertical shaft. **Honest limits.** Our crank turns the shaft directly, without his bevel wheels; printed parts, a box and a tin can stand in for his wooden float, tub and metal vessel. FDM prints hold food in their layer lines, so wash well and replace when worn. Your times and weights are the result.