The "head" is the control device to which the rotor hub is attached. The "hub" is the rotating part to which the rotor blades actually attach to.
Other than the metal rods & sleeves, there are only two parts to this original head design by Emilio Cabezas of Spain.
Arrow "A" points to the lateral pivot rod with a small brass sleeve bearing, prior to being installed in the upper control yoke.
Arrow "B" points to the lower pivot block. Look closely and you can see the small pivot hole that holds the pitch pivot rod. The pitch pivot rod allows the entire head to rotate fore and aft.
Arrow "C" points to a completely assembled unit. Yes, it is very small, the entire unit being only aproximately 2" x 2"
In the upper left you can see the fiberglass lateral control arm. Shown here on a card simply so it can be seen. Next to this, and in the is the center is the 1/8" music wire rotor shaft.
Photo #2 simply shows the upper yoke part, held on it`s side by a clip so you can see the small lateral pivot hole.
Arrow "A" points to the lower pivot block, where you can see the small pitch pivot hole. 
This photo is of the new, smaller, head being used on the "MICRO-MILLIE" .12 sized gyro. This head is only about 1.5" x 1.5" in size, and uses slightly smaller music wire pivot rods, and a 4x40 bolt for the lateral control arm rather than the fiberglass arm used on the previous head shown above. 
This final photo shows how the control rods (2-56) are installed on the MICRO sized gyro...... Installation on the MINNIE is very similar.
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