Centrifugal-Dasher Churn: Curved Wings on a Hollow Shaft Throw the Cream at the Wall, a Fixed Disk Turns It Back

"When the shaft h is made to revolve quickly the curved wings cause the cream to be thrown from the center to the circumference of the churn with so much force as to create a large amount of friction when it is being pressed between the wing or dasher extensions and the sides of the churn, and at the same time a strong current of air is carried through the body of the cream, and any cream that is forced out over the disk i, flows back into the center to be worked over."

Cut two 10 mm HDPE plates 256 mm across. Bore the top plate k 20.2 mm at the centre and six 20 mm openings n on a circle 80 mm across. Press a 10 mm stainless rod 20 mm long into the centre of the bottom plate k' so 10 mm stands below it as the pin m. Cut three stainless sheet wings 1.5 mm thick and 105 mm high, with three 15 mm tabs on each long edge; bend the tabs, curve each wing from 30 mm out at the hub to 122 mm out over 70 degrees and on for 30 degrees more nearly along the edge, and screw the tabs to both plates so the wings stand 105 mm between them. Screw three hardwood ribs 10 x 5 mm on the top of k and three under k', radial. Pass a 20 mm stainless tube 313 mm long down through k until its end is flush with k's underside, and hold it with a shaft collar each side of k. The tube is open at the top: it is the air pipe.

Use a 20-litre food-grade bucket as the body g. Set the step m on its floor and stand the dasher on it. Cut a 6 mm HDPE disk i to fit the bucket 150 mm up (282 mm across for ours), with a 100 mm opening in the middle, slide it down over the tube and press it until it wedges in the bucket's taper, so it cannot turn. Cut a 12 mm HDPE lid f to the bucket's top with a 32 mm hole, fit the printed bush in it, and screw three hardwood cleats under its edge that touch the wall; fix the lid by a screw through the wall into each cleat, above the cream.

Pin the pinion b on the tube with its teeth centred 40 mm above the lid. Cut two hardwood posts 50 x 25 x 118 mm, bore them 16.6 mm across 92 mm up, and screw them to the lid either side of the tube, one 60 to 85 mm in front of it and one 25 to 50 mm behind, as the stand e. Run a 16 mm stainless shaft c 180 mm long through them, pin the crown wheel a on it meshing the pinion, hold it with a shaft collar, and pin on a crank d of mild steel flat bar, 100 mm throw, with a hardwood handle.

Before fitting the lid, pour about 8 litres of heavy cream at about 15 °C, checked with the thermometer, into the bucket, so it stands just under the disk i. Fit the lid and pin the pinion. Turn the crank briskly, timing it. When the butter comes, unpin the pinion, take off the lid, lift out the disk and the dasher, take out the butter, pour the buttermilk into a bowl, wash the butter in cold water until it runs clear, salt and weigh it.

**John W. Kellberg** of Pittsburg, Allegheny County, Pennsylvania, US 30,409, 16 October 1860, "Churn". He claimed "the dasher and disk, made and operating substantially as described", and wrote that a churn on his plan completed a churning "in from four to six minutes"; we have not tested that. His gears were a bevel wheel and pinion on a cast stand; ours are a printed crown wheel and pinion on wooden posts. The patent does not say how the disk i is fastened; ours wedges in the bucket's taper. The patent gives no sizes; every size here is ours.