I was looking for a Christmas gift for my niece and nephew and thought of a backgammon board. This guy has an ingenious method of lining up his stock so he can align it repeatedly on the X axis (could use the same method on the Y). It appears to be very fast and very accurate and uses a straight bit to nudge two loose circular discs which are then carefully tightened in place.
The link skips ahead to that part of the video, about 4:44 from the start.
Hope this helps someone – I think I’ll try it on my next project!