Three-Crank Churn: One Dasher Strokes Up and Down While Two Side Dashers Swing In and Out

"My invention uses the old principle of the up and down dasher and for the purpose the greatest possible effective motion to the milk in a breaking or dashing manner, the side dashers having a lateral stroke are added, they are also designed to gather the butter after it is churned and press and work out the buttermilk."

From 20 mm hardwood make a box 500 mm long inside, 300 mm wide at the floor and 360 mm at the top, 380 mm deep, with square ends and the sides sloping out. Carry each end up as a post 80 mm wide to 650 mm above the floor, cut a 13 mm slot down its middle to 600 mm, and hinge a hardwood cap over the slot, held by a hook and eye. Glue two strips 20 x 20 mm up the inside of each end, 64 mm apart, as the stays N. Fill the box with water overnight so it swells tight, then empty it.

Cut the lid to lie on the box between the posts, in two parts: F, 360 mm long from one end, and F' for the rest, with a turn button K on F to hold F'. In F cut a slot P 40 mm square in the middle, and two slots 30 x 50 mm each side, 40 mm either side of the middle and 133 mm out from it, and bore each across for a 10 mm stainless pin: the pivots H.

Bend 12 mm stainless rod about 900 mm long, heating each bend red with the torch, into three cranks side by side in the middle: a middle crank of 40 mm throw, and a 25 mm crank each side of it, those two pointing opposite ways and both at right angles to the middle one. Make each crank pin 40 mm long. Leave 220 mm of straight shaft one side and 250 mm the other, and fit a hardwood crank handle on the longer end.

Make D a hardwood plate 498 x 60 x 20 mm, to slide between the stays, on a handle D' 30 mm square and 402 mm long, bored 12.6 mm 12 mm from its top. Make each side lever e 30 mm square and 514 mm long, bored 12.6 mm at its top and 10.4 mm 220 mm below it for the pivot, and screw a board E 440 x 120 x 20 mm across its foot. Set the lid on, D's handle through P and each lever in its slot on its pivot pin. Put the shaft in the posts' slots and close the caps, then join each crank to its handle with its printed link, fixed with washers and split pins.

Pour about 20 litres of heavy cream at about 15 °C into the box, checked with the thermometer, put F' on and turn the button. Turn the crank steadily, timing it; F' can come off to look. When the butter comes, unhook the caps, slip the middle link off its crank, lift out the shaft with the side dashers and lid F, and pour off the buttermilk. Put the shaft and side dashers back, add cold water, and turn the crank to work the butter and press the buttermilk out with the side dashers. Lift out the butter, salt and weigh it.

**Abel Austin** of Altona, Knox County, Illinois, US 25,553, 27 September 1859, "Churn". He disclaimed the shaft with cranks and the dashers with handles on their own, and claimed their arrangement with the links, springs, bearing box i, spring g and lid F F'. The patent gives no sizes; every size here is ours. His springs c on the links and spring g on the bearing boxes are here split pins and a hook and eye.