Look at the print below and notice on 1.00" intervals there is a fraction. The issue is you must find a centerline, then mark it off 90° to the centerline in one-inch intervals, ...and then take their bizarre fractions and convert them to decimals where you can accurately intersect the sweeping curves on a piece of layout paper. Then when you are finished, you cut it out as an overlay. Because of this and having multiple angles, sometimes you must make3, or 4, or 5 (-or more) templates and keep overlaying in both directions. When was the last time you used fractions such as 43/64th, 59/64th, 3/64th, 31/64th, 55/64th, 31/32nds, etc. to layout measurements on a wood item. Then you must layout a whole new set of sweeps when figuring the perpendicular angle of that wood piece. Again, we have found Ford's engineering prints for Wood to be very stressful to work with because missing one number generally changes the entire shape ...often turning that piece into firewood.