Oblique-Slat Barrel Churn: Rows of Slats Inside a Turning Barrel Point Opposite Ways and Throw the Cream End to End

"The slats A A A, etc., throw the cream toward an end of the churn (one portion of the slats throwing to one end and the remaining portion to the other end); as the cream is thrown violently toward the end it either strikes other slats, or the projections B B by either of which means its course is reversed and great agitation of the cream produced."

Cut 430 mm of food-grade PE pipe 315 mm across with a 12 mm wall. Cut two heads from 15 mm HDPE sheet to fit inside it and bore both 20 mm on the centre. Cut a door 200 x 120 mm in the pipe's side, between two rows of slats; keep the piece, screw two HDPE strips along its long edges so it rests on the pipe, and hold it with two hooks and eyes.

Cut four hardwood strips 30 x 18 mm, 390 long, and sixteen hardwood slats 90 x 12 mm standing 73 mm from the barrel's wall, a quarter of its 291 mm inside diameter; round their ends if you like. Set four slats in each strip, 100 mm apart, each at 45 degrees to the strip: in the first and third strips one way, in the second and fourth the other. Screw the strips inside the barrel a quarter turn apart, through the wall with stainless screws and lock nuts, sealed with silicone, so each row points the opposite way from the row before. Screw two hardwood projections B, 20 x 90 mm and 30 deep, on each head's inner face, opposite each other, between the rows.

Pass a 20 mm stainless shaft 680 mm long through both heads, press the heads into the pipe's ends, screw them through the wall and seal the heads and the shaft's passages with silicone sealant. Make a hardwood stand: a base 600 x 400 mm and two uprights 40 x 120 mm, 30 mm beyond each end of the barrel, bored 20.8 mm 260 mm above the floor. Rest the shaft in them with collars, and fit a hardwood crank 130 mm long with a dowel handle on its long end.

Turn the door uppermost, pour in about 8 litres of heavy cream at about 15 °C, checked with the thermometer, and close it. Turn the crank steadily, timing it. When the butter comes, stop with the door uppermost, open it, tip the buttermilk out into a bowl, take out the butter, wash it in cold water until it runs clear, salt and weigh it.

**Pearson Embree** of West Chester, Chester County, Pennsylvania, US 27,536, 20 March 1860, "Churn". He claimed the slats or projections on the inner surface, each row pointing obliquely in the line of motion and the next row the opposite way. He says they make butter "in much less time than by the ordinary revolving churns". The slat height follows his quarter-diameter; the PE barrel, the 45-degree angle, the counts and all other sizes are ours.