Was finally able to complete a print of the infamous shift knob this AM. Used Adam vice Eve this time and tried something completely different. I mounted the (white) filament on Eve and strung it across to Adam. It was much easier to monitor the slack and several times detected overwraps that would have not have been seen behnd the machine. I suspect that even minor tension on the filament will cause the type of problems I have been having. A good solution might be to mount the reels on the wall where they can be better observed and controlled. You definitely can't walk away and hope for the best. Design note: a scale factor of 1.007 (think Bond, James Bond) in software will account for the shrinkage on a 52mm sphere. Thanks to all who lended their advice and assistance, especially Allen.