Clockwork Vane Churn: A Wound Spring Turns Oblique Beaters, a Vane Sets the Pace and Airs the Milk

"The vane F, serves at once as a regulator of the motion of the beater, as well as a means of refrigerating and supplying fresh air to the milk chamber."

Print the milk chamber closed end down, the partition, the end plate, the beaters with supports, pinion C, wheel A, the ratchet, the catch, the bevel wheel, pinion E, the vane's hub, four vane wings and the crank. The chamber, partition and end plate need a 230 mm print bed. Print in PETG at 0.2 mm layers, 30 % infill, 4 walls; wash before first use.

Cut a pine base 380 by 260 mm and three cradles with a 221 mm round cut out of each; glue and screw them across the base under the end plate, the partition and the chamber's far end. Screw the end plate's two ties to the partition.

Cut 10 mm dowels 170 mm for S1 and 330 mm for S2. Wearing gloves, coil a spring steel strip about 12 mm wide, 0.4 mm thick and 650 mm long round S1, its inner end hooked in a saw cut in the dowel and its outer end bent round the post k. Thread S1 through the end plate and partition with the ratchet fixed on it by an M3 screw, wheel A loose beside it, the catch on A's post with a short piece of strip pressing it into the teeth, and the crank on its outer end. Thread S2 through both plates with pinion C pressed on to mesh A and the bevel wheel pressed on behind the partition. Put the upright shaft, a 10 mm dowel 100 mm long, in the partition's bracket with pinion E on its foot meshing the bevel wheel and the vane's hub on its top; push the four wings onto their arms.

Slide the beaters onto S2 beyond the partition and fix them with an M3 screw drilled through. Slip the milk chamber over them, S2's end in its far bearing, and bolt its flange to the partition with two M4 screws.

Pour 1.5 litres of heavy cream at about 15 °C, checked with the thermometer, through the hatch. Wind the spring with the crank and let it go, timing it with the stopwatch; turn the vane's wings flatter to run faster or edgewise to run slower, and wind again whenever it stops. When the butter comes, unbolt the chamber, pour off the buttermilk, wash the butter in cold water until it runs clear, work in a pinch of salt and weigh it.

**John F. Smith** of Galen, Wayne County, and **Wightman Brown** of Rose, New York, US 21,374, 31 August 1858. They enclosed the machinery in a case with tight sliding covers to keep its oil from the butter, covered the metal shaft with wood where it lay in the milk, and held each vane wing to its arm with a small spring. They did not claim an automatic churn as such, but the divided cylinder, the close case, the adjustable vane, the passage V and the ventilators working together. Our machinery is open and has no oil; our dowel shafts, friction-fit wings, strip spring and sizes are ours, and we have not timed how long it runs. FDM prints hold food in their layer lines, so wash well and replace when worn.