Swinging-Wedge Churn: A Wedge Dasher Sweeps a Curved Bottom and Strikes the Sloping Ends Squarely

"The churn tub being partly filled with cream, the dasher is moved back and forth. This operation causes the cream to be compressed between the inclined portions of the ends of the tub and the taper sides of the dasher and also to be kept in circulation, for as it is impossible for it to run back under the bottom of the dasher, it necessarily rises and falls over the top of the same back into the center of the tub."

Mark the pivot on two 20 mm hardwood sides and set out the inside outline from the notebook: the bottom an arc of 360 mm radius about the pivot, each end rising from it along a line 27.6 degrees from upright to a point 157 mm out and 149 mm below the pivot, then upright to 50 mm above the pivot. Cut the sides 20 mm outside that outline, rout a rebate along it, and bore each 17 mm at the pivot. Bend 1.5 mm stainless sheet, 260 mm wide, to the outline and screw it into the rebates with silicone sealant, the sides 260 mm apart inside. Fit four legs and a cover with a slot 36 mm wide, 150 mm long, across the middle.

Cut the wedge from hardwood 250 mm across: 110 mm wide at its top, 50 at its foot, 230 tall. Fix it on a 30 mm hardwood staff so its foot is 350 mm below the pivot. Make the cross-head a hardwood bar 40 x 30 mm across the tub, fixed on the staff, with a 16 mm stainless rod through it whose ends turn in the sides' holes. Above it bend a strip of stainless sheet 60 mm wide to a 45 mm radius round the pivot, reaching 80 degrees each way, and fix it to the staff as the guard F under the cover's slot. Make the hand rest a hardwood collar with a handle, held at any height on the staff by a set screw.

Pour heavy cream at about 15 °C into the tub, checked with the thermometer, about a third full (about 10 litres). Set the hand rest at a comfortable height and swing the staff steadily from end to end, timing it. When the butter comes, lift the cover and dasher out, take out the butter, drain the buttermilk, wash the butter in cold water until it runs clear, salt and weigh it.

**Josiah P. Fitch** of New York, US 26,841, 17 January 1860, "Churn". He claimed the curved guard F on the dasher staff with the dasher and tub, and the adjustable hand rest E with them. His dasher could be hollow, to hold hot water; ours is solid. The patent gives no sizes; every size here is ours, and setting the sloping ends along the wedge's faces at the end of its swing is our reading of "strikes ... squarely".