Pump Egg Beater: A Piston Draws the Eggs In and Out Through a Grate

"The eggs are broken into a vessel, the beater set into them. The piston being moved up and down by means of the crank draws the eggs in and out through the grate bars until they are completely torn in pieces or made perfectly fine and frothy."

Cut about 180 mm of 4.6 mm stainless wire. In the vice bend the wrist and the 7/8 inch crank at one end: a 6.4 mm wrist, then a 22.2 mm arm at right angles, measured centre to centre. Slide the straight end through the bearing from the tube's side, and 25.4 mm on bend the 2 inch crank, 50.8 mm centre to centre, opposite the first, then a 38 mm handle. Push a hardwood dowel, drilled 4.8 mm, on the handle as a grip.

Cut a 35.6 mm disc of 1.5 mm food-grade silicone sheet with a 3 mm hole, for Parker's leather. Cut a 3 mm stainless threaded rod 145 mm long and bend a 5 mm eye at one end with the round-nose pliers. Run two nuts up the other end, locked against each other 109 mm below the eye's middle, then a piston half crown up, the silicone disc, the other half crown down, and nut K. Tighten K until the disc's edge just stands proud of the halves: it should slide in the tube with a light drag.

Drop the piston into the tube from the top, hook the rod's eye over the wrist and squeeze the eye closed. Slip the band over the tube's lower end. Turn the handle: the piston runs down to just above the grate, and at the top of the stroke it rises out of the tube and drops back in. Turn the band so its openings line up with the tube's for the most stir, or part over them for less.

Break four eggs into a glass bowl. Stand the beater in them on its notched band, hold the loop handle and turn the crank about two turns a second, timing it. Lift it out when the eggs are smooth and frothy. Wash every part in warm soapy water; the piston comes apart at nut K.

**J. J. Parker** of Marietta, Ohio, US 25,038, 9 August 1859, "Egg-Beater or Churn". He claimed the tube A in combination with the band C and the grated bottom M. His sizes are kept: the tube, the openings, the band, the bearing height and the crank shaft. We read his "crank seven eighths of an inch long" as centre to centre, so its 1 3/4 inch stroke is longer than his 1 5/8 inch tube is deep and the piston leaves the tube at the top of each stroke. He does not name the wire gauge; 4.6 mm is No. 7 on the Birmingham gauge. Printed PETG stands in for his tin, and silicone for his leather; the rod, the piston's shape and the handle G's outline are ours.