A closer view from a slightly differing vantage point. The right end of the crossbox has been faced, to both flatten it and make the face perpendicular to the axle. In this view the spacer has been firmly been placed against the wheel hub collar, immediately inboard of the wheel. A bronze spacer ring will be machined to fill MOST of the gap between the crossbox and the spacer. A bit of room needs to be allowed for thermal expansion of the cross box, if not things will get really hot as the crossbox grows longer and gets bound between the spacer and the ring gear hub.

Photo by Bill Liebman