DeLong Escapement
The story is that Charles DeLong sold the idea to the Illinois Watch Co. management to fit a number of watches with his new escapement. He was working for Illinois at the time. The story diverges on exactly which watches were so fitted. However, one version says that 100 Abe Lincoln watches were fitted with the escapement and tested for rate in positions, isochronism and temperature.
At the end of the testing, the watches were taken down and thoroughly cleaned and examined. When they were oiled and re-assembled, they would no longer run reliably. DeLong after considerable study determined that the jewel settings on the pallet and escape wheel arbors were slightly eccentric and the tolerance on the new escapement were sufficiently tighter than on a standard lever that it would not perform properly with the small mis-alignment that had resulted.
DeLong's solution to this problem was to develop concentric jewel settings that could be maintained to a very close tolerance. However, by the time he had completed this work, the company had lost interest in using the escapement.
DeLong continued to fit the escapement to a number of watches up until the time of this death. He succeeded in getting Hamilton/Ball to incorporate the escapement into probably 100 production watches, but this development eventually ran out of steam also. Since the example watch with serial number 2,768,400 was finished in 1915 and DeLong completed development of the escapement at the end of 1915, I believe this example is one of the original Illinois Abe Lincolns.
The general notion is that there are probably between 10 and 20 of the original Abe Lincoln watches in existence and about 100 each of the Ball and Hamilton 992 watches that were fitted with the escapement. In addition to these, my friend Wade McDaniel had a small vial with about 50 escapements in it that DeLong had told him were removed from watches he had fitted with the escapement from the period of 1920 to 1940.