Reacting Churn Dasher: Two Rows of Oars Pitched Opposite Ways

"This mode of constructing the dasher gives it great advantage over the ordinary churn dasher as by the employment of paddles arranged in the manner stated no vacuum is created interfering with the operation of the churn, consequently there is no mingling of air with the cream to obstruct the gathering of the butter."

Print the knob upright (/uploads/blueprints/reacting-churn-dasher-knob.stl), with supports in its sockets. Its square sockets are turned 45° so each oar's blade takes its pitch, the upper row one way and the lower row, under the gaps, the other. Print twelve oars flat (/uploads/blueprints/reacting-churn-dasher-oar.stl). Print in PLA at 0.2 mm layers, 30 % infill, 4 walls; wash before first use.

Glue the twelve oars into their sockets. Glue a 12 mm hardwood dowel, as long as the bucket is deep plus 150 mm, into the top of the knob. Press a cork into the seat under the knob so it stands proud of the end.

Drill a 20 mm hole in the centre of a food-grade 20-litre bucket's lid for the rod.

Let the heavy cream stand until it reaches about 15 °C, checked with the thermometer. Pour in 1 litre, fit the lid over the rod, and work the dasher up and down like a common dasher. 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.

**Peter Van Antwerp** of Coeymans, Albany County, New York, received US 2,957, dated 16 February 1843. The knob was about three inches of the rod's lower end, enlarged; the paddles were "broad and flattened at their outer ends where they project into the cream, tapering from thence to their inner ends"; the centre hole could be filled with cement or putty and closed with cork "or other elastic substance" to keep the churn's bottom from being bruised. He claimed combining with the rod the two series of paddles arranged above each other and operating as described. **Honest limits.** A printed knob and oars stand in for his wooden ones, and a bucket for his churn. FDM prints hold food in their layer lines, so wash well and replace when worn. Your times and weights are the result.