Now in the CAD software we add items like the Spar location...

and then the alignment pin locations.

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At this point I have moved to the third computer in this operation. I use several due to some of them being dedicated to specific tasks, and while running, I like to leave them alone.

Here I am setting the "Z" axis to zero. I use a sheet of paper, and fine tune until I feel a firm drag on the paper as I pull it under the router bit. 1/8 inch end mill/straight router in this case.