Inclined-Stop Air Churn: Diagonal Stops That Hold the Cream and Gather the Butter

"The great advantages of these double inclined stops to the churn are, that in the process of churning they serve to hold the cream and affect a reaction, and thus offering a greater resistance to the revolving dashers, thereby making the beating operation more perfect, 2d that in the process of gathering the butter after churning, the dashers B are turned backward, this produces a rapid rotary motion of the cream which drives it up the double inclined stops. The second inclination throws it off to the center, collecting the butter in a mass around the vertical shaft."

Print two stops flat on a long face (/uploads/blueprints/inclined-stop-air-churn-stop.stl): right-angled triangular bars about 200 mm long, split in two to fit your bed if needed. Print the hollow dasher upright with supports (/uploads/blueprints/inclined-stop-air-churn-dasher.stl): a hollow shaft with two hollow cross-tubes cut off obliquely, and air holes near its top. Print the air wheel (/uploads/blueprints/inclined-stop-air-churn-air-wheel.stl). Print in PLA at 0.2 mm layers, 30 % infill, 4 walls; wash before first use.

Take a food-safe box about 170 mm each way. Bed a stop diagonally across each of two adjoining sides in silicone, right angle down, the low ends at the left bottom corner when the dasher turns right to left, as they set them. Drill a seat in the floor's centre for the dasher's foot and the lid's centre for its shaft.

Stand the dasher's foot in its seat and pass its top through the lid. Push the air wheel on the square top just under the lid's top, so the air holes stay above the cream, and glue a crank arm and dowel handle above the lid.

Let the heavy cream stand until it reaches about 15 °C, checked with the thermometer. Pour in 1.5 litres. Crank so the long points of the cross-tubes go first; time until the butter comes. Then crank backward a while, as they did, so the stops throw the cream to the centre and gather the butter round the shaft. 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.

**George E. Gill and Joseph B. Tillinghast** of Chillicothe, Ross County, Ohio, received US 6,538, dated 19 June 1849. Their churn had "a step a in the center of the bottom, (the churn had better be of a cubical form)"; the air wheel at the top resembled a water wheel; the horizontal dashers were elliptical tubes cut off obliquely at each end, the long point going first. They called the churn so improved "one of the best in the country"; that is their claim. They claimed "the introduction of the double inclined stops." **Honest limits.** A food-safe box and printed parts stand in for their wooden churn; our crank turns the shaft directly, without their gearing, so at hand speed the cream climbs the stops only a centimetre or two, as the notebook shows; gathering may take longer than in theirs. FDM prints hold food in their layer lines, so wash well and replace when worn. Your times and weights are the result.