The attached image is a demonstration of how the zero 100 arm works. The centre point is the main arm pivot, the point to its left is the auxiliary pivot.The two circles are the arcs described by the headshell pivots. Since the distances between all these pivots are fixed, the result is a series of lines which describe the attitude of the headshell (the short lines between the two arcs near the top of the drawing.
I have drawn lines between each of these segments and the notional disc centre. I have drawn three lines back from three selected segments to the other end of the diameter of the Thales circle. Thales rule establishes that any triangle which is circumscribed by a circle and has one side which is a diameter of that circle is a right triangle.
The diagram is based on the best information I have on the zero 100. If you can get me accurate measures of the distances between the pivots, the distances between each of the "base" pivots and the platter centre and the exact orientation of the line between the "base" pivots and the lines between them and the platter centre I can improve the accuracy of the drawing.
I should then be able to calculate the correct alignment.
I realised that the diagram I posted missed some crucial information, namely the angles between the line joining the headshell pivots and the lines joining pivot #2 to the disc centre.
Here they are. As you can see the angular error across the arc is 0.11 degrees which is +/- 3.3 minutes. To achieve this with Baerwald's alignment would require an arm almost 5 metres long.
Mark Kelly (Vinyl Asylum inmate, Thanks Mate!)