I guess this isn't common knowledge?
I don't have the ability to measure it accurately without leaning on a machinist friend. I clamped it down to a tablesaw with the bulge from the steerer tube hanging over the edge, and then added and subtracted to get to the middle of the fork blades at the top (same as center of steerer tube), and the center of the axle. It is looking like it may have been 1-1/2", although on mine one side is more than that and the other side is less.
Thanks for the heads up on BikeCad. I had not seen that.