Collaboration
ART
BEAUTY & WELLNESS
CRAFT
CULTURE & HISTORY
ENTERTAINMENT
ENVIRONMENT
FOOD & DRINKS
REVERSE ENGINEERING
SCIENCES
SPORTS
TECHNOLOGY
WEARABLES
Twin-Crank Slide-Top Churn: Two Dashers on a Bent Crank Shaft, Sliding Plates Keep the Milk In
Cable L. Gilpatrick · Public domain
Buttercup

Created by

Buttercup

11. November 2026IE
1
0
0
0
0

Twin-Crank Slide-Top Churn: Two Dashers on a Bent Crank Shaft, Sliding Plates Keep the Milk In

Cable L. Gilpatrick of Saco, Maine, received US 25,405, dated 13 September 1859, for a churn. A crank shaft bent into two opposite cranks rides on two posts above a box and works two dashers, so one goes down as the other comes up. Each dasher is two boards crossed and bored with holes. The staffs pass through holes in two slides that move in casings on the top, following the staffs so the milk cannot splash out. The patent gives no sizes; every size here is ours.
Intermediate
About 2 days, plus printing

Instructions

1

One up, one down

Loading Jupyter Notebook...
2

Two dashers in one box, a few weeks before

Campbell rocked his two dashers on a lever. Gilpatrick drives his from a bent crank shaft and covers the top with slides.
3

Read US 25,405

"Motion is then communicated to the dashers by means of the crank-shaft. As one dasher descends, the other ascends. Thus the milk is kept in contant agitation, which is necessary in order to churn expeditiously. The slides being operated upon by the dasher-staffs prevents the milk from splashing out, as it otherwise would do."
4

Print the staff collars

Each collar is two halves round a crank pin: the lower half with a 30 mm square socket for the staff, and a cap; two M5 screws close them. Print two sets. PETG, 0.2 mm layers, 40 % infill, 4 walls.
Design FileSTLCC0 - Free
Download Model
5

Box A and its posts

From 20 mm hardwood make a box 400 x 360 mm and 450 mm deep inside, with a bottom. Make the two 400 mm sides 170 mm taller, narrowed to posts 120 mm wide above the box, and bore each post 13 mm, 600 mm above the bottom's underside, for the shaft. Glue and screw a cleat 20 mm square along the inside of each post side, 30 mm below the rim, for the top. Fill the box with water overnight so it swells tight, then empty it.

Materials for this step:

Hardwood BoardHardwood Board3 pieces
Wood GlueWood Glue1 piece
Wood ScrewsWood Screws30 pieces

Tools needed:

Table SawTable Saw
Hand SawHand Saw
Cordless DrillCordless Drill
Drill Bit SetDrill Bit Set
Bar ClampBar Clamp
Try SquareTry Square
Tape MeasureTape Measure
WaterWater
6

Crank shaft D and crank E

Cut 12 mm stainless rod about 750 mm long. Heat each bend red with the torch and bend it in the vise into two cranks of 50 mm throw, pointing opposite ways, each crank pin 50 mm long, their middles 180 mm apart. Check the journals line up by rolling the shaft on the bench. Thread one end through a post, the collars' lower halves onto the pins, and the other end through the other post. Fix a hardwood crank E, 160 mm long with a handle, on the end that sticks out.

Materials for this step:

Stainless Steel RodStainless Steel Rod1 piece
Hardwood BoardHardwood Board1 piece
Hardwood DowelsHardwood Dowels1 piece
Wood GlueWood Glue1 piece

Tools needed:

Propane TorchPropane Torch
Bench ViseBench Vise
HammerHammer
Heat-Resistant GlovesHeat-Resistant Gloves
HacksawHacksaw
Files (Hand File)Files (Hand File)
Cordless DrillCordless Drill
Drill Bit SetDrill Bit Set
Tape MeasureTape Measure
7

Top A', casings F and slides H

Cut the top to drop onto the cleats, with two slots 140 x 50 mm across it, under the cranks, and a finger hole. Over each slot build a casing F: two rails 20 x 26 mm, 370 mm long, 80 mm apart, with a strip on each that overhangs the inside by 8 mm, and an end block at each end, leaving 346 mm inside. Cut each slide H 240 x 79 mm from 18 mm hardwood, so it slides under the strips, with a hole 34 mm square in its middle, 4 mm bigger than the staff.

Materials for this step:

Hardwood BoardHardwood Board2 pieces
Wood GlueWood Glue1 piece
Wood ScrewsWood Screws24 pieces

Tools needed:

Table SawTable Saw
RouterRouter
Mortise ChiselMortise Chisel
Wooden MalletWooden Mallet
Cordless DrillCordless Drill
Drill Bit SetDrill Bit Set
SandpaperSandpaper
Bar ClampBar Clamp
8

Staffs B and dashers C

Cut two staffs 30 mm square, 480 mm long. For each dasher, half-lap two boards 180 x 50 x 15 mm into a cross, bore eight 12 mm holes, cut a 30 mm square hole in the middle, and glue the staff's end into it. Set the top on its cleats, pass each staff up through its slide's hole, and bolt the collar's cap over its pin and onto the staff's top, turning the cross so its arms point to the box's corners.

Materials for this step:

Hardwood BoardHardwood Board1 piece
Wood GlueWood Glue1 piece
Machine ScrewsMachine Screws4 pieces
Flat WasherFlat Washer4 pieces
Nylon Insert Lock NutNylon Insert Lock Nut4 pieces
PETG FilamentPETG Filament1 piece

Tools needed:

FDM 3D PrinterFDM 3D Printer
Table SawTable Saw
Mortise ChiselMortise Chisel
Wooden MalletWooden Mallet
Cordless DrillCordless Drill
Drill Bit SetDrill Bit Set
Screwdriver SetScrewdriver Set
SandpaperSandpaper
9

The build in 3D

FreeCAD model of this build, one side and the lower part of one post cut away: the box, the bent crank shaft on its posts with crank E, the two staffs in their collars, the dashers, and the slides in their casings on the top. The crank was turned through 24 positions.
Design FileBLENDCC0 - Free
Download Model
10

Churn

Lift the collars' caps off, take out the top, pour in about 15 litres of heavy cream at about 15 °C, checked with the thermometer, and put the top and caps back. Turn the crank steadily, timing it. When the butter comes, take the top out, lift out the butter, drain the buttermilk, wash the butter in cold water until it runs clear, work in a pinch of salt and weigh it.

Materials for this step:

Heavy CreamHeavy Cream15 l
Coarse Sea SaltCoarse Sea Salt1 piece
WaterWater1 piece

Tools needed:

Leave-In Probe ThermometerLeave-In Probe Thermometer
StopwatchStopwatch
Digital Kitchen ScaleDigital Kitchen Scale
Stainless Steel Mixing Bowl (Large)Stainless Steel Mixing Bowl (Large)
Screwdriver SetScrewdriver Set
11

Troubleshooting

Twin-crank churn troubleshooting.

Flow

Loading...
12

History and honest limits

**Cable L. Gilpatrick** of Saco, Maine, US 25,405, 13 September 1859, "Churn". He claimed the crank shaft D and staffs B with the top A', "when said top is provided with boxes (F,) in which play slides, through which the staffs pass". The patent gives no sizes; every size here is ours. His collars are not described beyond "passing around said cranks"; ours are printed and split so the top can come out.

Materials

12

Tools Required

24

Design Files

2

This blueprint makes

Thumbnail
Placeholder

Butter

Free

198
0
1
Thumbnail
Placeholder

Buttermilk

Free

72
0

Related Blueprints

These blueprints share knowledge with this one — techniques, materials, or principles that connect them in the learning graph.

Hinged-Float Double-Dasher Churn: Floats That Close Going Down and Fall Open Coming Up

Hinged-Float Double-Dasher Churn: Floats That Close Going Down and Fall Open Coming Up

by ButtercupIE

Woodworking

1
0
0
0
0
0
Star-Dasher Crank Churn: Geared Crank and Flywheel Drive Two Notched Dashers Set Point Over Gap

Star-Dasher Crank Churn: Geared Crank and Flywheel Drive Two Notched Dashers Set Point Over Gap

by MartinNO

Woodworking

2
0
0
0
0
0
Churning Butter from Cream — The 5,000-Year-Old Fat Separation

Churning Butter from Cream — The 5,000-Year-Old Fat Separation

by TheChefDK

CRAFT

60
0
0
0
0
0

CC0 Public Domain

This blueprint is released under CC0. You are free to copy, modify, distribute, and use this work for any purpose, without asking permission.

Support the Maker by purchasing products through their Blueprint where they earn a Maker Commission set by Vendors, or create a new iteration of this Blueprint and include it as a connection in your own Blueprint to share revenue.

Discussion

(0)

Log in to join the discussion

Loading comments...