Early 1920's Hilco Variocoupler. Working condition

Description

Early 1920's Hilco Variocoupler. Very rare. In the early days of radio experiments and constant improvements, before it was named a variocoupler, it was called a Scientific Apparatus! I bought this years ago just because it was a unique part of radio history, never used it, however it is a working varicoupler and could be used if desired. The sticker was in rough shape and wanting to come off, expected with something this old, so I professionally clear coated the entire apparatus to preserve it from any further deterioration. To connect to the center coil you use the mounting bracket and the knurled nut on top, it reads roughly 243uh. The outer coils max reading is about 609uh and everything inbetween using the wire taps. If desired you could modify it and turn into a variometer, but I wouldn't recommend it unless you could easily reverse the change without destroying it's original design. Collector's item or radio project. 1/4" shaft