Skeleton-Semisphere Dasher Churn: Arched Ribs Over the Upper Dasher Roll the Cream Back to the Centre

"The office of the circular disk form dashers is to agitate the cream near the bottom of the churn, while that of the skeleton semisphere is to agitate it near the center of the height of the churn."

Print the lower dasher (/uploads/blueprints/skeleton-semisphere-dasher-churn-lower-dasher.stl), the upper dasher with its tube (/uploads/blueprints/skeleton-semisphere-dasher-churn-upper-dasher.stl) disk down, four ribs (/uploads/blueprints/skeleton-semisphere-dasher-churn-rib.stl) flat, pinions D (/uploads/blueprints/skeleton-semisphere-dasher-churn-pinion-d.stl) and E (/uploads/blueprints/skeleton-semisphere-dasher-churn-pinion-e.stl), the wheel F (/uploads/blueprints/skeleton-semisphere-dasher-churn-wheel-f.stl), the step (/uploads/blueprints/skeleton-semisphere-dasher-churn-step.stl), the cover (/uploads/blueprints/skeleton-semisphere-dasher-churn-cover.stl), the standard (/uploads/blueprints/skeleton-semisphere-dasher-churn-standard.stl) and the crank (/uploads/blueprints/skeleton-semisphere-dasher-churn-crank.stl). Print in PETG at 0.2 mm layers, 30 % infill, 4 walls; wash before first use.

Cut a 10 mm square hardwood strip 320 mm long as the solid shaft and sand it. Set the step in the bottom of the pot and stand the shaft in it. Slide the lower dasher on, its boss 4 mm above the step, and fix it with an M3 screw drilled through the shaft. Press the four ribs' feet into the upper dasher's rim and their heads into the collar, then lower the upper dasher's tube over the shaft.

Lay the cover on the pot with the tube through its centre and a washer over it. Slide pinion D onto the flat at the tube's top, so the upper dasher hangs from it. Fix pinion E on the shaft above it with an M3 screw drilled through the shaft. Screw the standard to the cover from below with two M4 screws, push a 10 mm dowel through it as the axle, press wheel F tight onto its inner end so it meshes with D below and E above, and fix the crank on its outer end with an M3 screw drilled through the dowel.

Pour in 3 litres of heavy cream at about 15 °C, checked with the thermometer. Turn the crank steadily and time it with the stopwatch: the disks turn opposite ways and the ribs roll the rising cream back toward the centre. When the butter comes, lift out the cover and dashers, pour off the buttermilk, wash the butter in cold water until it runs clear, work in a pinch of salt and weigh it.

**W. H. Tambling** of Berlin, Marquette County, Wisconsin, US 20,740, 29 June 1858, signed 8 June 1858, assigned to Aaron Hilton. He drew four ribs but would use six, eight or more as needed, smaller semispheres of fine wire ribs inside them, or the semisphere made like a coarse wire screen. He also suggested a complete skeleton sphere, the lower dasher made semispherical to match. He claimed only the semisphere on the upper dasher of a reverse-acting churn. Our pot, sizes, gear counts and printed parts are ours. FDM prints hold food in their layer lines, so wash well and replace when worn.