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Welcome Licorice Pizza (LP) lovers! Setup guides and Vinyl FAQ.

Allen's alignement points are 57.8mm and 129mm

If you recalculate the alignment points from Allen's data they come out to 57.8mm and 129mm.

I checked this with Brian Kearns (who knows more about alignment than anyone else I know). Brian corrected my calculation and sent me a spreadsheet that generates the new alignment points for any set back. His method involves calculating a null point difference which is subtracted from the inner null point and added to the outer. The difference length is given by

D = - (n2-n1)/2 + SQRT (((n2-n1)/2)^2 - s^2 + 2s.SQRT(Le^2 - ((n1+n2)/2)^2)) Where n1 and n2 are the original null radii, Le is the original effective length and s is the setback length. For an arm of 225mm length the delta is 8.2mm when setback is 1.27mm so the null points are 57.8mm and 129.1mm.



Mark Kelly


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