Segmental-Stave Churn: Thick Curved Staves Split the Cream's Current, a Long Blade Sweeps Beneath Them

"The dash blades are caused to revolve by turning the crank S, the bevel face (k-l) of the blade striking against the cream causing a portion of it to pass up the incline face (k-l) and fall down on the line (l-m) while a portion is thrown from B, to B, with a rebound, and a portion forms an “eddy” and backward current in the “lee” of the thick edge of, B."

Use a wooden tub 270 mm across inside at the floor, 300 mm at the top and 380 mm deep. From hardwood cut three segments to lie against the wall over 60 degrees each, thin at one edge and rising on a quarter circle to 44 mm thick at the other, 330 mm tall. Bevel each one's foot upward towards the middle, from 50 mm up at the wall to 95 mm at its thick edge. Glue and screw them inside, a third of the way round from each other, all thick edges facing the same way round. Glue the bearing cup in the middle of the floor. Fill the tub with water overnight so it swells tight, then empty it.

Turn a hardwood shaft 30 mm across and 400 mm long, its foot turned to 19 mm for 11 mm, and fit a 12 mm stainless pin 52 mm long in its top for the pinion. Cut five blades 40 x 15 mm and shave each to a wedge, its two faces bevelled opposite ways. Make the lowest 256 mm long and the other four 164 mm. Mortise them through the shaft at positions 25, 100, 160, 220 and 280 mm above the tub's floor, each at right angles to the one below.

Cut a round cover in two halves to rest on the staves' tops, with a 32 mm hole for the shaft. Hinge a hardwood cross piece M, 60 x 20 mm, across the tub's top with a strap hinge on one side (g2), resting on a cleat on the other (g3), bored 14 mm for the shaft's pin. On it screw two chairs carrying a 12 mm stainless shaft R with the crown wheel and a crank S, and pin the pinion on the shaft's top so the two mesh. Lift M on its hinge to free the shaft.

Pour in heavy cream at about 15 °C, checked with the thermometer, from a few litres up to about 12, put the cover halves and the cross piece down, and turn the crank steadily, timing it. When the butter comes it rises to the top: lift M and the cover, take the butter out, drain the buttermilk, wash the butter in cold water until it runs clear, salt and weigh it.

**Thomas A. Jebb** of Buffalo, New York, US 26,109, 15 November 1859, "Churn". He claimed the short dash blades H and the long blade H2 arranged with the segmental stave B, the short blades turning within and the long one under its bevelled end, and the blades' arrangement with the staves. His thick staves are single solid staves of the tub "leaving no interstice in the stave for the milk to lodge in and get sour"; ours are segments fixed inside a bought tub. His bevel pinion and wheel are here a printed pinion and crown wheel. The patent gives no sizes; every size here is ours.