Many years ago I ownedtwo Graf Studioball heads, one right after the other. I was very proud of them, real pride in ownership. The first one came apart within a year : the body of the beast got a little wobbly and then separated from the panning base. THe second one did the same nine months later. It is buried in Mississippi river mud about fifty feet (maybe more) beyond the minor league baseball stadium in Davenport, Iowa. I was in Davenport shooting an annual report. I replaced it with the head I should have bought in the first place: An Arca-Swiss B1 Monoball, sent via first morning priority delivery FedEx.
Hopefully the ones GRAF makes today are better built.
And hopefully you'll have better luck with yours than I did with mine.