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Self-Folding Blade Dasher Churn: Six Blades to Churn, Reverse and They Fold to Two That Gather
Robert W. Davis let the cream set the dasher and the butter fold it.
Robert W. Davis of Rodgersville, Steuben County, New York, received US 10,566, dated 28 February 1854, for "Churns for Making and Working Butter": a dasher of two end pieces B carrying blades a, and divided end pieces C hung loosely on pins "set eccentric to the axis of the dasher," carrying blades b and scroll-curved blades c. Turned one way, the cream's resistance opens it "so as to present six centripetal cutting or agitating blades"; reversed after the butter comes, the butter's resistance closes it "so as to present but two centrifugal gathering blades," which gather the butter, work it into rolls and expel the buttermilk.
This rung works out the strokes and the turning moment, then prints the end pieces, sections and blades, builds the round-bottomed churn, and makes and works butter.
Advanced
About 5 hours, plus printing
Instructions
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Six blades or two
Six blades or two
Loading Jupyter Notebook...
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A dasher that changes when reversed, before it
A dasher that changes when reversed, before it
The embedded blueprint's floats fall back onto rollers when the crank is reversed. Davis's sections fold six blades into two S-shaped gatherers.
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Read US 10,566
Read US 10,566
"The blades, c, c, have a greater curvature given them in line of a scroll, than those, b, b, as seen in the drawing. This increased curvature commences from the termination of the curve of the blades, b, b, as seen in the drawing. This increased curvature prevents the dasher throwing the butter toward the center of the churn, while gathering and working it."
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Print the parts
Print the parts
Print two end pieces B (/uploads/blueprints/self-folding-blade-dasher-churn-end-piece.stl), four sections C (/uploads/blueprints/self-folding-blade-dasher-churn-section.stl), four outer blades for a and b (/uploads/blueprints/self-folding-blade-dasher-churn-outer-blade.stl) and two scroll blades c (/uploads/blueprints/self-folding-blade-dasher-churn-scroll-blade.stl). Print the blades on their lug ends. Print in PETG at 0.2 mm layers, 30 % infill, 4 walls; wash before first use.
Materials for this step:
PETG Filament1 pieceTools needed:
FDM 3D Printer5
5
The round-bottomed churn
The round-bottomed churn
Lay a round food-grade container about 180 mm across and 180 mm long on its side in a pine cradle and cut a lid opening in its top. Drill both ends on the axis for a 10 mm square hardwood shaft and fit a crank arm and dowel handle outside.
Materials for this step:
Food-Grade Storage Container1 piece
Pine Board1 piece
Hardwood Dowels1 piece
#8 x 1" Wood Screw1 piece
Wood Glue1 pieceTools needed:
Coping Saw
Cordless Drill
Drill Bit Set
Hand Saw6
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Assemble the folding dasher
Assemble the folding dasher
Slide the two end pieces onto the shaft inside the churn and screw an outer blade a across each pair of ends. On each side, hang a section on each end piece's pin hole with a 4 mm stainless pin, then screw an outer blade b across the sections' outer ends and a scroll blade c across their inner ends. Fit a short pin in each end piece as a stop so the sections open about square to B and fold back flat against it.
Materials for this step:
Mild Steel Rod1 piece
Machine Screws1 pieceTools needed:
Hacksaw
Screwdriver Set
Cordless Drill7
7
The build in 3D
The build in 3D
FreeCAD model of this build, not of the patent: the round-bottomed churn cut open, the end pieces with blades a on the square shaft, and the sections swung open across them on their pins, as for churning.
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Churn one way, gather the other
Churn one way, gather the other
Let the heavy cream stand until it reaches about 15 °C, checked with the thermometer. Pour in 1.5 litres. Turn the crank the way that opens the sections and time until the butter comes. Draw off the buttermilk, then reverse the crank so the sections fold and the two S-blades gather and roll the butter. Pour off the buttermilk, add cold water, churn a little and pour off again until it runs clear; work in a pinch of salt and weigh the butter.

Materials for this step:
Heavy Cream1500 ml
Coarse Sea Salt1 piece
Water1 pieceTools needed:
Leave-In Probe Thermometer
Stopwatch
Digital Kitchen Scale
Stainless Steel Mixing Bowl (Large)9
9
Sections that will not swing
Sections that will not swing
Self-folding blade dasher troubleshooting.
Flow
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History and honest limits
History and honest limits
**Robert W. Davis** of Rodgersville, Steuben County, New York, received US 10,566, dated 28 February 1854. He divided the end pieces C diagonally "in the line of a cima reversa" so the blades' edges always meet them as they open and close; his Fig. 2 showed the open position in red lines, which do not survive in the black-and-white scan. He claimed dividing the end pieces C, eccentric to the dasher's axis, combined with the blades a, b, c, so the dasher adjusts itself by the resistance of the cream and then, reversed, of the butter.
**Honest limits.** A container, printed parts and stop pins stand in for his churn and diagonal joints; he gave no sizes, and our blade curves are read from his figures. The notebook's force is illustrative. FDM prints hold food in their layer lines, so wash well and replace when worn. Your times and weights are the result.
Materials
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Tools Required
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Design Files
1Related Blueprints
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Post-and-Float Butter-Working Churn: Floats Revolving Astride Fixed Posts
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CC0 Public Domain
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