Turning-Tub Churn: A Crank Spins the Tub on a Geared Pedestal Against Two Fixed Triangular Beaters Held From Standards

"Now, if the crank H is turned, the tub I, and disk D will receive a rotary motion, and the centrifugal force, tending to throw the fluid to the walls of the tub, the beaters at the same time tending to throw the same fluid back toward the center, the cream or milk has thus two forces constantly acting upon it, one a centrifugal, and the other a centripetal."

Glue up a hardwood base A 40 mm thick, a 400 mm circle with ends 120 mm wide running out to 700 mm overall. Cut a 30 mm slot 120 mm long along each end for the standards' feet. Roll a strip of 1.5 mm stainless sheet 168 mm wide into a cylinder B 310 mm across, rivet the lap, and screw it to the base through small tabs. Screw three hardwood posts C 40 mm square and 170 tall inside it, 110 mm from the centre and a third of a turn apart, the first at the back. Bore the cylinder 16.6 mm at the front, 97 mm up, for the crank shaft.

Bore the base's centre 8.4 mm and run an M8 bolt up through it with a nut each side, its head the step G, so it can be screwed up or down. Set a stainless tube F 30 mm long round it. Cut a 16 mm stainless spindle E 185 mm long; pin the cog wheel E' on it with its teeth 150 mm above the base. Screw a hardwood bearing block C' 40 x 25 x 120 mm to the base 55 to 80 mm in front of the centre, bored 16.6 mm across 97 mm up. Run a 16 mm stainless crank shaft 250 mm long through the cylinder and block, with the wheel G pinned on its inner end meshing E' from below and its end stopping clear of the spindle, a shaft collar against the block, and a crank H of mild steel flat bar, 100 mm throw, with a hardwood handle.

Cut an 18 mm HDPE disk D 330 mm across, bore it 16.2 mm at the centre and fix it on the spindle's top. Screw under it a bead H, an HDPE ring 230 mm across outside and 210 inside, 2 mm thick, and on top a flange ring D' 300 mm across outside and 282 inside, 15 high, that the bucket's foot just drops into. Screw the step G up until the bead just touches the posts' tops. Use a 20-litre food-grade bucket as the tub I; for the patent's set screws J, two machine screws through the flange bearing on the bucket's foot.

Plane two hardwood beaters L to a triangle 40 mm a side, 330 long, and bore a 10 mm hole through each lengthwise for air. Cut two hardwood supports M 50 x 40 x 65 mm with a triangular socket below for a beater's top and a 20 mm square socket above for a stem; glue the beaters in. Cut two hardwood stems N 20 mm square, 170 long, and fit each in its support. Make two standards P 40 x 40 mm, 650 tall, each on a foot Q 60 x 80 x 20 mm with a carriage bolt down through the base's slot and a wing nut Q' under it, so the standards slide in and out; let each stand in a socket in its foot (R) so it lifts out. Fix a hardwood arm O 30 mm square across the top of each standard, reaching in to its stem, with a 20 mm square hole and a wing-nut clamp bolt so the stem can be set higher or lower. Cut an HDPE cover K 304 mm across in two halves, notched for the stems.

Set the bucket in the flange and pour in about 8 litres of heavy cream at about 15 °C, checked with the thermometer. Set the beaters close to the wall and reaching near the bottom without touching, and lay on the cover halves. Turn the crank steadily, timing it, not so fast that the cream climbs to the rim. When the butter comes, keep turning a little so it gathers in a mass. Lift off the cover and beaters, lift the bucket off the disk, take out the butter, pour the buttermilk into a bowl, wash the butter in cold water until it runs clear, salt and weigh it.

**M. C. Longacre** of Cleveland, Cuyahoga County, Ohio, assignor to himself and R. R. Herrick, US 31,355, 5 February 1861, "Churn". He claimed "rotating the body of the churn in a vertical position by means of the disk (C) or its equivalent, when connected with the stationary dashers (L) arranged as described, for the purpose of adjusting the same both vertically and horizontally". His text uses the letters G and H each for two parts (the step and the driving wheel; the bead and the crank). His gears were bevel wheels; ours are a printed pinion and crown wheel, and our drum is stainless sheet. The patent gives no sizes; every size here is ours.