Folding-Lever Dasher Churn: The Dash Rod Folds Two Levers and Swings the Agitators Side to Side

"It will be readily seen by reference to Fig. 2 that the operation of the levers and agitators is of such a character as to force the cream rapidly from one side of the churn to the other, and that such currents must be forcibly interrupted by the agitators upon either side"

From 20 mm hardwood make a box 400 x 320 mm and 420 mm deep inside. Glue two strips 15 x 15 mm up the inside of each end, 90 mm apart, as the ways x. Fill the box with water overnight so it swells tight, then empty it.

Cut two end posts 89 x 14 mm, 460 mm long, to slide between the ways, and a top bar 400 x 40 x 30 mm with a 31 mm square hole in its middle for the dash rod; screw the bar across the posts' tops. Screw a block 16 x 24 x 24 mm to each post's inside 25 mm each side of the middle and 110 mm up, and bore them 10.4 mm for the pivot rods b'.

Bore two hardwood bars 20 mm square and 336 mm long through their length, 10.4 mm, and pin each on a 10 mm stainless rod 396 mm long that turns in the blocks. In the middle of each bar fix a lower arm, 110 mm between its pin holes, pointing up and out, and fix two blades 54 x 50 x 8 mm at right angles to it, pointing down and out, staggered so the two bars' blades pass each other. Join each arm's end to an upper lever, 180 mm between pins, and both upper levers to the foot of a dash rod 30 mm square and 550 mm long, with 10 mm stainless pins, washers and split pins. Glue two agitator bars f, 16 mm square and 340 mm long, across each upper lever.

Pour about 25 litres of heavy cream at about 15 °C into the shell, checked with the thermometer. Slide the frame down the ways and work the dash rod up and down steadily, timing it. When the butter comes, lift the frame out whole, gather the butter, drain the buttermilk, wash the butter in cold water until it runs clear, salt and weigh it.

**N. B. Cooper** of Gratis, Preble County, Ohio, US 26,020, 8 November 1859, "Churn-Dasher". He did not claim jointed levers or agitators on them, "as these devices are well known", but "the arrangement of the arms d, d, on the two pivots b', b', one on each side of the upright B, when the upright B is made removable, by means of the ways x, x". The patent gives no sizes; every size here is ours. His central upright is here the top bar's guide, and the rod is worked by hand rather than by gearing and a crank.