Spatter-Guard Spring Dasher Churn: A Funnel-and-Bowl Block on the Lid Keeps the Cream In, a Spring Lifts the Dasher

"Press down g; C being attached will be carried down by it, thus compressing B. When down B will immediately expand and raise g to the same point again and so it will continue to operate making the labor of churning to consist merely in pushing down the dasher."

Use a 20-litre food-grade bucket as the common churn. Cut a 12 mm HDPE lid F 304 mm across with a 30 mm hole in the middle. Cut two hardwood boards 220 x 40 x 16 mm, cross them, and screw them to the foot of a 25 mm hardwood handle g 1000 mm long.

Glue up hardwood and turn a block A 90 mm across and 90 mm tall. Bore it 27 mm through the middle, so the handle is wiped as it rises. Turn the top into a funnel E, 60 mm across at the top narrowing to the bore 40 mm down, and hollow the underside into a half-round bowl d 70 mm across.

Get a compression spring about 73 mm outside, 280 mm long free and about 0.15 N per mm (16 turns of 3 mm wire). Turn a hardwood head block C 90 mm across and 30 thick, bored 26 mm. Bore its side 8.5 mm to the bore, let an M8 hex nut into the hole's mouth with glue, and run in an M8 threaded rod 50 mm long with a wing nut locked by a hex nut on its outer end: the thumb screw s. Fix one end of the spring to the rim of A's top and the other under C, each under a screw and washer, so A, B and C lift off as one.

Pour about 10 litres of heavy cream at about 15 °C, checked with the thermometer, into the churn, stand the dasher in, and put on the lid. Slide A, B and C down the handle until A rests on the lid. Raise the handle to the top of its stroke, about 150 mm above where the dasher meets the bottom, and turn the thumb screw tight. Push the handle down and let the spring lift it, steadily, timing it. When the butter comes, loosen the thumb screw and lift A, B and C off the handle, take out the dasher and butter, pour the buttermilk into a bowl, wash the butter in cold water until it runs clear, salt and weigh it.

**John M. Buell** of Zanesville, Muskingum County, Ohio, US 29,460, 7 August 1860, "Churn". He claimed "the device A constructed as described, in combination with the churn, spring B, handle g, and head block C". His churn was the common staved dasher churn with its own lid; ours is a bucket. The patent gives no sizes; every size here is ours.