You need the 90° axis because otherwise, the strongest RG (pin axis) and second strongest axis (MB/PSA) would add up, and the result would be a new strong axis between both, depending on the weight distribution.
Remember: the MB is only the second strongest force that works once the core rotates. You need the pin axis to have the core move into its stable end position, and the MB to define how fast and in which shape this happens.

The 90° angle is just logical, anything else would mean that the strongest rotational axis would be instable - the PSA HAS to be on a plane that is 90° to the pin axis, otherwise the laws of physics as we know it (except Lane #1 ) would not work.

Besides, i am sure that you can tinker with the MB and move it away from the marked spot. But it would still be on a 90° plane to the axis through the pin/the highest RG of the core, making a drilling result rather unpredictable.
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DizzyFugu - Reporting from Germany

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