You're right, there should be even spacing all around, and it should of course move freely.
Was it perhaps shipped with locking screws to safeguard the arm from vibration? Or should have been but wasn’t? If you can link to a lot of good clear pics or diagrams this can probably be enough to point you in the right direction.
Was it perhaps shipped with locking screws to safeguard the arm from vibration? Or should have been but wasn’t? If you can link to a lot of good clear pics or diagrams this can probably be enough to point you in the right direction.