Hi!
This weekend, I worked on one of my bike and wanted to overhaule the hubs.
After I replaced the bearings, packed with grease, I started adjusting the cones. I found the good adjustment (as loose as possible without any play right ?) and then I proceeded on tightening the locknut.
To my great surprise, it seems that the axle moved when doing so, resulting on my adjustment to get loosened!!

I don't understand why that is happening. Do I need a vise to put my axle in so that it doesn't move ?

I hope my explanation was clear enough