Counter-Blade Slide Churn: Two Sets of Blades Turn Opposite Ways, the Outer Set Slides Out to Gather

"When the aggregation of the oleaginous particles has progressed to a considerable extent, it is found beneficial to move the slides B of the outer blades so as to increase the distance between the two systems of blades for the better collecting of the newly formed butter."

Print head H with its hollow shaft, head H', two outer slides and two inner slides flat, pinions P and P', wheel W, the cover, the standard and the crank. Print in PETG at 0.2 mm layers, 30 % infill, 4 walls; wash before first use.

Cut a 10 mm square hardwood strip 170 mm long as the solid shaft and sand it. Fix head H' on its lower end with an M3 screw drilled through the boss and the shaft. Push the inner slides into H' from opposite sides, their blades' outer edges 50 mm from the centre, and the outer slides into H, their edges 80 mm out, measured with the ruler; lock each with an M3 set screw. Slide the solid shaft up through H's hollow shaft.

Pass the hollow shaft up through the cover with a washer over it and slide pinion P onto its flat, so the outer blades hang from it. Fix pinion P' on the solid shaft above with an M3 screw drilled through, so the inner blades hang from it. Screw the standard to the cover from below with two M4 screws, push a 10 mm dowel through it, press wheel W tight on its inner end to mesh P below and P' 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, and set the cover on. Turn the crank steadily and time it with the stopwatch. When the butter begins to gather, lift the cover out, slide the outer blades out to 95 mm, lock them and turn on. When the butter has come, pour off the buttermilk, wash the butter in cold water until it runs clear, work in a pinch of salt and weigh it.

**N. H. Sherburne** of Campton, Kane County, Illinois, US 20,898, 13 July 1858. He disclaimed turning the two parts of an agitator opposite ways, and agitators with movable parts, broadly, and claimed the heads H, H', the slides B, the blades C, C' and the shafts S, S' turning opposite ways, in combination. He gave no way of fixing the slides; our set screws are ours, as are the pot, sizes and printed parts. FDM prints hold food in their layer lines, so wash well and replace when worn.