Shifting-Gear Grinding-Disk Churn: One Crank Wheel Is Thrown Into Gear With the Wings Below, the Grinding Disk Above, or Both

"By having the wheel H, attached to the bar G, and the latter arranged as shown, the disk b, may be rotated without the shaft B, or the latter may be rotated without the former or both rotated simultaneously as may be desired. This is an important feature of the invention for it is frequently necessary to use the disks without the wings or gatherers and vice versa."

Glue up a hardwood box A 300 mm wide, 360 long and 320 deep inside, from 20 mm boards, joints sealed with silicone sealant. Bore one end 16.6 mm at 80 and 240 mm above the inside floor on its centre line for the shafts B and E, and the far end 16.6 mm at 80 mm for B's other bearing. Cut a hardwood lid with a 14 mm hole 25 mm off the centre line and 13 mm in from the geared end, for the hopper's spout.

Cut a 16 mm stainless shaft B 432 mm long. Screw two pairs of hardwood wings C 70 x 80 x 20 mm through hardwood hubs on it, a quarter turn apart, one pair 70 to 150 mm from the geared end and one 220 to 300. Run it through both ends with shaft collars and pin a pinion D on its outer end 6 mm outside the box.

Cut a 6 mm HDPE disk a 120 mm across with a 60 mm centre opening, glue twelve HDPE ribs 26 x 6 x 3 mm radially on its face, and screw it inside the geared end on three 10 mm stainless standoffs 25 mm long, around the upper shaft hole, ribs inward. Cut a 16 mm stainless shaft E 120 mm long, push it through the end and the disk a's opening, pin the disk b on its inner end with its ledges 3 mm from a's ribs, and the pinion d on its outer end. Set the hopper F in the lid so its spout drops into the space behind a, beside the shaft.

Cut a mild steel flat bar G 470 x 24 x 6 mm, drill it 12.2 mm for H's axle 210 mm from one end and a row of 6 mm holes near the other end. Make two hardwood guides: e, a block with a slot just wide enough for the bar, screwed to the geared end level with the gap between the pinions; e', with a slot 60 mm tall so the bar's end can rise and fall, and a row of 6 mm holes across it. Fit a 12 mm stainless axle in the bar, the wheel H on it between the two pinions, and a crank handle on H's face. Slide the bar into the guides and hold it with a 6 mm pin a* through e' and the bar.

Pin the bar so H meshes the disk's pinion d only. Turn the crank and pour about 12 litres of heavy cream at about 15 °C, checked with the thermometer, slowly into the hopper, timing it; it is ground between the disks and falls to the bottom. Then move the bar so H meshes the wings' pinion D (or both) and turn to gather the butter. Lift the lid, 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 Fowler** and **W. L. Walter** of Homer, Cortlandt County, New York, US 32,939, 30 July 1861, "Churn". They did not claim the disks or the wings, which were known, but "the arrangement of the sliding or adjustable bar G, with the wheel H, attached and arranged in relation with the pinions D, d, of the shaft B, and disk b". Their drawing shows H's crank as a pin on its face and a handle on the bar's end for shifting it. The patent gives no sizes; every size here is ours.