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Further analysis - We selected three comparison mvts, two model 1860, 16S KW mvts, s#250913 and s#380267, and one model 1868 SW-LS, s#470173. The dials from all samples fit into the chronometer example perfectly, one pushing on nicely, the others falling right in. Pin-holes in the feet are at the correct depth. The relative position of the barrel, center wheel, third wheel and fourth wheel is identical in all examples. The hour wheel and minute wheel diameters and teeth are identical, only the chronometer has been provided with longer cannon post, and expanded cannon on the hour wheel. The relative positions of the dial train are some 90 degrees different in the sample mvts from the chronometer; the latter has the minute wheel center aligned with the escape wheel cock locator pin, while the samples have the minute wheel center aligned between the fourth wheel and escape wheel positions. The samples all have screw-holes and locator pin-holes for their pallet bridges, absent from the pillar plate of the chronometer, which only has its escape and balance wheel jewels, hole for the detent jewel tail and adjacent screw for detent depth adjustment. Now here is the interesting part: the 16S KW mvts (called model 1860) have cock foot locator pins in the same position as the chronometer, with the slightest differences that will not allow interchanging the cocks between one another; at the same time the model 1860 cock feet want to skew slightly toward the upper plate edge. The model 1868 balance cock interchanges with the chronometer, pressing on snugly, without any such skewing and with matching alignment. So there must be this subtle difference between the model 1868 KW and the model 1860. We conclude that this mvt is a KW model 1868, specially designed for chronometer escapement.
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