Anyone have experience with the slimline pro pencil? The mechanisms seem to be of poor quality. I snapped the threaded end off one when assembling the pencil. Once assembled the mechanisms felt "sticky". I sold a couple but then my daughter took one to college with her and she says it keeps jamming and breaking the lead. Needless to say they are getting pulled from inventory for the show this weekend. Has anyone else tried these and if so what did you think of the mechanisms?