Thank you for all the kind words, I just enjoy fixing stuff!
For those who are interested in the mechanics, Richard and others...
The internals of this Arca Swiss Monoball head are quite interesting.
The ball itself is beautifully turned from aluminium, probably magnesium. The gripping mechanism for the ball is very simple, although I wasn't able to access it completely, it seems the shaft with the main tensioning and locking knob has both left and right hand threads, probably M8 ISO thread. When clamping, there is a semi concave clamp which grips the lower half of the ball on two sides and also presses it upwards into a similar concave pad at the top of the main body. It's as simple as that.
The three security screws are a clever reversal of a countersink, hard steel, grip to tighten but cause a screwdriver to 'cam out' if an attempt is made to undo the screws. I suspect while the main ball mechanism is simple and robust, it may be pretty close tolerances to assemble, hence the "keep out" screws. There does not appear to be a spring in there.
The rotation clamp at the base is also very simple. The three 3mm countersunk screws secure a inverted cone, when the clamping knob is tightened it clamps a corresponding collar against the cone, increasing friction until, when sufficient pressure is applied, it effectively locks.
The machining is to a very high standard, the finish of the internal parts is immaculate. The damping is effected with thick, sticky grease, which I tried to avoid disturbing.
In short a joy to work on.
