I just received a Fatboy that I got in a lot of razors. When I unscrew the bottom knob I can pull the knob back and forth about 1/4 inch opening and closing the razor. It seems to lock up tight, there seems to be a groove on the shank that maybe is for some kind of snap ring. Anyone know an easy fix of is it just something I need to live with. By the way I'm very handy and have lot of tools but I read here that there's a crimped ring of some kind and that a razor once taken apart is difficult to put back together. Thanks Bob.