I bought one and the centering cones were such a sloppy fit, and held with setscrews iirc.Or get one of these for $40. I love mine.
https://www.harborfreight.com/motorcycle-wheel-balancing-stand-98488.html
And the moment you lock them down they're thrown off center? I'll save my $40I have one and have used it to build several wheels. Never had any problems. You just have to make sure that the cones are pushed tight before you lock them down.
TOOLS
Why would it be off center? Are you actually trying to center the hub/wheel in the stand? You just mount the hub/wheel, and clamp a wire pointer on, and that is where you set to center. I will still keep using mine, and enjoy having the extra $30.00 the other one cost in my pocket.And the moment you lock them down they're thrown off center? I'll save my $40