Poul Ladegaard's Air Bearing Tangential Tonearm!
Photo of the final arm built according to sketches in 'arm2.jpg'. Note that you can add mass to the 'floater' and trim the lateral inertia. This is difficult with most conventional arms (using a sliding tube arrangement).
If you don't have enough space on the plinth for arranging the floater symmetrically like this, you can place the arm at the side of the floater and add weight on the other side to balance the floater. It's important that it has the mass center on the middle, or else more air will be needed.