Wooden Insulator Pins

Millions of insulator pins to hold the glass insulators used on telegraph and telephone poles are used every year, and so great is the demand for them that woods specially suited for their manufacture have become quite valuable. The pins are small, round pieces of wood from one and a quarter to one and a half inches in diameter and about eight inches long, turned with a taper thread on the upper end, with a projecting shoulder below, beneath which the pin is turned to about an inch and three-sixteenths to fit the hole of the pole or cross-arm. The pins must be made of a wood that will not shrink nor swell much, and for this purpose black locust has been found the most suitable. Large tracts of black locust have for this reason become very valuable and the wood finds a ready market.