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Show Bamboo Needle of the Phonograph Process Wood Must Go Through It was F. D. Hall of Chicago who discovered the bamboo needle of the phonograph. The Scientific American relates the many woods with which he experimented before he found the right one and describes the intricate I processes that the bamboo goes , through before becoming a needle, j The hard point of the needle is , formed from the enameled cortical surface of the cane. The poles, 20 feet long and from 2 to 314 inches in diameter, di-ameter, carefully selected, are sawn into pieces about an inch long and split in two. Machines split these again into prism-shaped blanks for needles. To force out the sap and replace re-place it with oil and wax in the myriad cells of the cane, the bits are put in drip kettles and lowered into vats laden with an oily mixture at 340 degrees de-grees Fahrenheit, where they remain 40 hours. Then they go into tumbling barrels containing hardwood sawdust, where they get cooled and polished. Each needle is inserted by hand into a cutting machine that snips the point into the familiar triangular form at the rate of 30,000 needles a day. |