Toothed-Disk Pass Churn: Cream Poured In Passes Once Between Fixed Toothed Disks and a Toothed Wheel Spinning Between Them

"The tendency of the wheel while in rapid motion is to prevent the too free flow of the milk through the disks, and by retaining it between the disks until it has had the effect of a number of revolutions of the wheel, the butter globules are all broken ... It has been found that the great amount of friction in the passage of the cream through the disks caused by the teeth, is sufficient to churn it thoroughly in being once passed through."

Use a 20-litre food-grade bucket and set the socket F in the middle of its floor. Cut a 6 mm HDPE ring 200 mm across inside and pressed down until it wedges in the bucket's taper about 244 mm up. Cut a 16 mm stainless shaft E 425 mm long. Screw two hardwood beaters T 240 x 30 x 8 mm, tilted 20 degrees, on hardwood hubs pinned to the shaft 60 and 150 mm above its foot, a quarter turn apart. Stand the shaft in the socket, slide the disk B down it onto the ring, then the wheel C, pinned on the shaft 14 mm above B's face, then the disk A on B's rim, and screw A to the rim through four holes so they are closed tightly together.

Cut a 12 mm HDPE cover L to the bucket's top, bored 16.8 mm at the centre for the shaft and 12.6 mm 55 mm off it, over the cup, for the conductor O: a 12 mm stainless tube 100 mm long with a small kitchen funnel on top. Pin the cog wheel H on the shaft 40 mm above the cover. Screw two hardwood bearing blocks 50 x 25 x 118 mm to the cover 60 and 125 mm in front of the centre, bored 16.6 mm across 93 mm up, run a 16 mm stainless shaft 150 mm long through them with the wheel I pinned on its inner end meshing H, a shaft collar, and a crank J of mild steel flat bar, 100 mm throw, with a hardwood handle.

Turn the crank briskly first, so the wheel spins, then pour about 10 litres of heavy cream at about 15 °C, checked with the thermometer, slowly into the funnel, timing it. Keep turning while it runs through the disks into the bucket below, and on a little with the beaters so the butter gathers. Lift off the cover and the disk pack, take out the butter, pour the buttermilk into a bowl, wash the butter in cold water until it runs clear, salt and weigh it. Take the pack apart to wash it.

**Wm. Jackson** and **Joseph Clarke** of Syracuse, Onondaga County, New York, US 32,250, 7 May 1861, "Churn". They claimed "the employment of the disks A. and B. with their concentric rows of teeth, as specified in combination with the central wheel C", and wrote that one pass churns the cream thoroughly; we have not tested that. Their teeth were pyramids; ours are square pegs. They do not say how the disk pack is held; ours sits on a ring wedged in the bucket's taper. Their wheels H and I were bevel gears; ours are a printed pinion and crown wheel. The patent gives no sizes; every size here is ours.