The Knock-Down Bird Cage: Four Rods, Six Parts, Nuts for Feet

"The nature of my invention consists in making a bird-cage separable in its parts by the devices and arrangements herein set forth". "These nuts 8 also form the feet or supports for the cage when resting upon the floor or on a table." "It will be seen from the drawings that when the bolts or rods 7 are withdrawn the cage is detached into six separate and distinct parts—to wit, the four panels, the bottom, and the top—and by this arrangement the cage can be readily taken apart for cleaning or for transportation-packing."

Cut eight hardwood bars for the panels' tops and bottoms: four 30 cm long for the sides and four 20 cm long for the ends. Halve both ends of every bar with a saw and chisel, so that at each corner a side bar and an end bar overlap to the thickness of one bar. Clamp each pair of bars together and drill matching holes 2 cm apart, then glue dowel rods between them as the bars of the panel. Stand the four panels in a rectangle with their halved corners overlapping, and drill a hole down through every corner, top and bottom, for the threaded rod. Cut a plywood bottom and a plywood top and drill them at the corners to match. Push a threaded rod down through each corner, through the top, both panels' bars and the bottom, and screw a nut onto each end. Stand the cage on its four lower nuts and check it stands level. Time how long it takes to take apart into six parts and put back together.

**Mary Pitts** of Chicago filed US 702,993 on 14 February 1901; it was patented 24 June 1902. Her connecting rods were metal, "larger in cross section than the wires forming the panels", and the bars under the bottom plate left it "in a condition to be easily cleaned when it is detached". **Honest limits.** The notebook treats the parts as flat slabs and ignores the rods and nuts. Sizes are examples. Your timings are the measurement.