I got a cosmetically mint condition Underwood Star for free recently and I'm looking to get it running and restored for my sister. Anyway, the big stumbling block is the escapement, specifically the ratchet wheel. This one looks like a top hat with a machine screw going through it. This assembly takes two sizes of ball bearings, one race is inside the narrow portion of the "top hat" of the escapement wheel. This bearing size is 1.2mm. When this assembly screws into the base of the whole escapement, the "brim" of the hat, which engages with the escapement dogs, sits on a set of bearings itself. These bearings are not the same size as the race is much larger in both the wheel and the escapement base plate. I'm looking to find out what size this larger set of bearings is. Can't find much specific about the later Underwood portable escapements, let alone a ball bearing size. Any help is appreciated.
Thanks all!
Phil Forrest