Mark Bartholomew: I purchased 3 corkscrews on Ebay that I have a question about. > They all are similar. They look like the last 3 inches of an antler. The cut off end has a collar, then a "spike" projects out of the antler. The spike is very sturdy and looks like a toothpick, but about 10 times the size. What is the purpose of the "spike"?
Ron: From your description I believe your corkscrews are a late 19th century type sometimes referred to as the "Adelaide". The handles are normally goat horn with a nickel plated brass or German silver (white brass) ferrule or collar. The spike or "wire breaker" was used to break the wire or string that was often used to hold the cork in place.
They were manufactured mainly in England (by M. Dickson, C.J. Johnston, C. Lockwood & others) but examples have also been found marked Germany. The English models usually have the shaft passing through the handle using a nut or rivet head mechanism to hold in place. Models made in Germany usually have a short transverse pin driven through the handle attach the shaft. From the examples that surface they must have been produced in considerable number. Adelaide corkscrews were made with a wire helix or a web helix.
Above is a picture of four different examples: Two fitted with wire helix - one marked DICKSON has a pointed nail type wire breaker and the other marked LOCKWOOD has a square cross section breaker. One fitted with a web helix has a with a uniquely shaped curved wire breaker marked RD. NO 42353 (1886) with the shank marked with the logo (flag pole & flag) C.J. JOHNSTON. The fourth is an unmarked German web helix example with a steel transverse pin through the handle.