I really try to avoid using axle collars and would consider them a last resort, as they can change the way the axle flexes. I always make sure the grub screws are tight. Sometimes I tighten them, then back them up 1/2 turn and retighten them. I also try to use the same screw locations each time I change an axle. It gives the screw something to bite into, and it keeps the axle cleaner by not dimpling it up all over, which makes it easier to change in the future. Blue Loctite on the screws will help keep them from loosening up, if that’s what is happening.
Best of luck!
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