This is a double wheel gage , used to lay out lines for mortises .
I set the outside wheel to 12.7 mm . I set the inside wheel to
9.52 mm . I angle the gage and mark the face with the 12.7 mm
wheel . I angle the gage and mark the edge with the 9.25 wheel .
Elapsed time is just over 1 second , 1.5 seconds max .
Contest closed .