Dog-Power Tappet Churn: Tappets on the Tread-Wheel Rock a Shaft That Works the Dasher

"The end of the arm A, at E, is moved by the projecting arm c, of the tread-wheel, until it slips or escapes over the projecting arm c, when the lower end of the other arm A, is immediately caught by another projecting arm c, of the tread-wheel on the opposite side of it, and moved in an opposite direction to the first arm A…"

From 70 mm square timber make a platform 2470 by 2300 mm: two side beams 2300 long, two end beams and a centre beam 2330 long between them, screwed with 3-inch screws. Lay a 2470 mm sill on the ground at the front and join it to the front beam with three strap hinges. Stack concrete blocks under each back corner: each block raises the slope about 5 degrees; we use three, 14.3 degrees. Check it with the angle finder.

Glue and screw two layers of 18 mm plywood into a disc 1700 mm across, the second layer's seams across the first. Under it glue a ring 150 mm wide at the rim and a 300 mm square hub block. Screw eight pine cleats from 150 to 680 mm out for the dog's grip. Bolt one flange bearing on the centre beam and one on a bridge 200 mm above it; run a 30 mm steel axle up through both and the hub, and cross-bolt it to the hub with an M10 bolt.

Cut five tappets 300 mm long from the timber. Bolt each on top of the wheel with two carriage bolts, from 700 mm out to 150 mm past the rim, 72 degrees apart.

Stand a post 1340 mm tall on the middle of each side beam, braced front and back with 3-inch screws. Bolt a flange bearing to each post's inner face, 1260 mm up, and bore 40 mm through the left post. Pass a 30 mm shaft 2655 mm long through them. Hang an arm 960 mm long from the shaft on each side, its inner face 20 mm outside the rim and its foot 45 mm below the tappets' tops, cross-bolted to the shaft.

Cross-bolt a 760 mm arm F to the shaft outside the left post, square to it. Drill it 330 mm each side of the shaft for the points H. Rip pine into two rods G 45 by 20 mm, drill them with several holes, and pin one to each end of F with an M10 bolt. Screw two crossed boards 240 mm long to each rod's foot as the dasher, cut a slot in each bucket lid, and stand a bucket under each rod so the dasher stops 40 mm above the floor.

Stand a post on the back beam 450 mm right of the centre and run a bar from it over the wheel, its underside 430 mm above the wheel, ending 450 mm behind the wheel's centre; brace it under. Fit an eye bolt under the bar's end for the lead.

Use a harness, never a collar, clipped to the eye bolt so the dog stands right of the centre facing up the slope. Start on one block with treats until it walks calmly. Pour about 9 litres of heavy cream at about 15 °C into each bucket, checked with the thermometer, and put the lids on. Time the run with the stopwatch. When the butter comes, pour off the buttermilk, wash the butter in cold water until it runs clear, work in a pinch of salt and weigh it.

**Addison G. Brush** of Great Bend, Susquehanna County, Pennsylvania, US 20,545, 15 June 1858, "Operating Churns". He made the tread-wheel heavier at or near the periphery to steady and equalize its motion, set the stroke by the length of arm F, which may work two churns, and gained power and rapidity of stroke by raising the side of the frame. He claimed the revolving platform with its tappets working the dasher through arms A, A, F and shaft B. He gave no sizes: ours, the five-tappet timing, the steel shaft in bearings for his gudgeons, the dog bar and the buckets are ours. Rod G leans about 2 degrees over the stroke, so keep the lid slots loose.