Front, Back, Dial, Movement, Cuvette, Case mark, Cuvette mark
The Grade 104 was Illinois' first attempt at a high grade nickel finished movement. It was soon followed by the much more elegant Grade 105. There may have been fewer Grade 104's produced than even the scarce 105. This example is cased in a Ladd Patent Case that originally housed an Aurora 5th pinion. The movement was found in a lot of uncased movements at a local auction.
The Illinois 5th pinion movements were the expression of an idea to use a basic hunting cased movement for an open face case by adding another idler pinion at appropriate position to carry the seconds bit in an open face case. Since the seconds bit would end up at 3:00 when the non-5th pinion movement was cased in an open face case, the position of the seconds bit needed to be moved 90 degrees to the 6:00 position. This was accomplished by adding an idler pinion on the opposite side of the third wheel from the normal 4th wheel and pinion. The third wheel pinion lies midway between the 4th and 5th pinions and about the same distance from the center (2nd) pinion. At a casual glance the 4th, 3rd and 5th pinions seem to lie in a straight line.