Counter-Rotating Egg Beater: One Wheel, Two Beaters Turning Opposite Ways

"This invention consists in arranging in an adjustable frame two beaters, one inside the other, which receive motion in opposite directions by means of two pinions which gear into a large bevel wheel and on opposite sides of the same, so that by rotating the bevel wheel by means of a handle the beaters receive the required motion."

Print the 48-tooth crown wheel (/uploads/blueprints/counter-rotating-egg-beater-crown-wheel.stl) and two 12-tooth pinions (/uploads/blueprints/counter-rotating-egg-beater-pinion.stl). Print in PETG at 0.2 mm layers, 30 % infill, 4 walls.

Cut a plywood upright and two arms. Bolt the crown wheel to the upright on an M5 screw with washers so it turns freely, and fix a handle screw near its rim. Drill the arms 5 mm on the line through both pinions' centres.

Cut 200 mm of 5 mm rod. Epoxy one pinion on it to mesh at the wheel's top, and bend two wire loops 28 mm across at its lower end.

Glue the second pinion to a length of silicone tube sleeved loosely over the rod, meshing at the wheel's bottom. Bend two wire loops 48 mm across and fix them to the sleeve's lower end, round the inner beater.

US 23,694 drawing sheet, public domain (expired patent).

Clamp the frame to the table over the bowl with two egg whites. Turn the handle about once a second and time how long until they hold stiff peaks.

**James F. Monroe** of Fitchburg, Massachusetts, and **E. P. Monroe** of New York, assignors to E. P. Monroe, received US 23,694, dated 19 April 1859, reissued 16 October 1860 (No. 1,062). The frame's fork clamps to a table with a set screw and washer. The second pinion lies loose on the arbor, driving the outer beater whose lower collar turns loosely round the arbor's end. They noted it also mixes paint. **Honest limits.** FDM prints hold food in their layer lines, so wash well and replace when worn. A crown wheel and spur pinions stand in for his bevel gears, and a silicone sleeve for his loose pinion. Your times are the result.