The Turning-Plug Thread Former: A Plug That Turns With the Bottle and Leaves a Screw in the Neck

"The plug C, is represented as having two angular scores a, a, made spirally upon it, so as to form a two threaded left handed male screw, the angle of the scores nearest or next to the apex, being made at a right angle to the center of the plug and the angle next to the base forming an acute angle with the center of the plug; the latter so as to give such a form to the orifice K, of the bottle Fig. 3, as will permit the cork to be readily forced in" "What I claim as my invention in the construction of tools for forming screw threads, angular or other scores in the necks and orifices of glass, earthen, or other bottles, and other articles, is— Making the plug which forms the interior of the orifice, to turn with the bottle, jug, or other article while the material of the orifice is worked around it, substantially as described."

**Plug.** Print a plug that tapers from 24 mm at its base to 18 mm at its tip over 35 mm, with two left-handed spiral scores 6 mm apart, each square to the axis on the side toward the tip and sloping on the side toward the base, and a 4 mm hole through its length. Make it about 12% larger than the neck you want, for the clay's shrinkage. **Spindle.** Fix the plug on a hardwood dowel and pass the dowel through a hole in a hardwood block clamped to the wheel's frame, so the plug turns freely point down over the wheel's centre. **Neck.** Throw a small bottle on the wheel and close it in to a thick neck. Grease the plug with petroleum jelly, lower it into the neck, and shape the neck round it with the clay tools while the wheel turns: the plug turns with the bottle, as Stone's did, and the clay is pressed into its scores. Leave it until leather-hard, then turn the plug out by hand the way that unscrews it. **Fire.** Dry the bottle slowly and fire it in the kiln at the clay's stated temperature. **Test.** Fill the bottle with water and push in a squeezed cork. The next day, drive the button corkscrew in until its button meets the cork, keep turning the same way, and see the cork rise out.

**Amasa Stone** of Philadelphia, Pennsylvania, received US 13,402, dated 7 August 1855. His plug C was pierced with a hole I through its length and a hole J through the spindle to let air in and out of the bottle; the spindle E turned in a block G on pivots H, H between the legs of the forceps. He described the same turning plug for the insides of telegraph insulators. After his death, Sarah T. Stone, administratrix of his estate, entered a disclaimer limiting the patent to glass, disclaiming earthen ware and other materials. **Honest limits.** Stoneware on a potter's wheel stands in for glass worked hot in the forceps, because glass cannot be worked at home this way; the patent, as limited by the disclaimer, covers glass. The plug's sizes are not Stone's. The notebook ignores the cork's squeeze and friction; its pitches and heights are examples. Your unscrewed cork is the result.