Air-Bucket Churn: Buckets That Carry Air Down and Cream Up

"When it is desired to form butter with this churn, the case or box is filled with cream to a point a short distance above the level of the journals. The buckets are then revolved in the direction in which their open sides face, causing their said open parts to strike the surface of the cream nearly parallel, and the air contained in them to be carried below the surface and discharged into the cream, and to ascend through the same in the form of globules."

Print the bucket wheel upright (/uploads/blueprints/air-bucket-churn-bucket-wheel.stl), with supports: two buckets on parallel arms round one hub. Print two end pieces (/uploads/blueprints/air-bucket-churn-end.stl) and the crank arm (/uploads/blueprints/air-bucket-churn-crank-arm.stl). Print in PLA at 0.2 mm layers, 30 % infill, 4 walls; wash before first use.

Cut a 0.5 mm stainless sheet 160 mm wide and about 340 mm long, deburr it, and bend it round a 140 mm form into a U with 60 mm straight sides. Seat it in both end pieces' grooves in silicone.

Pass a 10 mm square hardwood journal, rounded where it runs in the ends, through one end, the wheel's hub and the other end. Glue the crank arm and a dowel handle on its outer end. Cut a plywood lid with a hole in its centre for air.

Let the heavy cream stand until it reaches about 15 °C, checked with the thermometer. Fill the case to a little above the journal. Fit the lid and crank the way the buckets' open sides face; 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.

**Nathan Chapin** of Cortlandtville, Cortland County, New York, received US 5,560, dated 9 May 1848, reissued 15 May 1849 as No. 137. A cast plate on one arm took the squared end of the journal; a curved plate in a groove outside the frame let the journal be withdrawn and the buckets removed. He wrote that the buckets bring "the oxygen of the air in continual, and frequent contact with the fatty substances of the cream"; that is his explanation, not a measured fact. He claimed "forming the paddles of the revolving wheels with buckets of the peculiar shape above described." **Honest limits.** Stainless sheet and a printed wheel stand in for his case and buckets. The notebook gives an upper bound, not a measurement. FDM prints hold food in their layer lines, so wash well and replace when worn. Your times and weights are the result.