Found a couple more.
This is a spacer, used as a fixture for widening a steel wheel.
The length of the spacer corresponds to the final wheel width.
We used to widen wheels by preserving the front half (thereby keeping the dimensional integrity between the wheel spider and the front face of the rim) and by cutting the back portion off the wheel.
A new back portion, from a different wheel and with an additional 2", would then be fixtured to the front face/spider, using this spacer as a checking fixture.
A small plate was affixed in four locations, allowing for minute adjustments of the donor portion. Once the radial and lateral runout are within spec then the two halves can be welded together.
Here is a finished sample, a 10" Corvette rally with the front spacing preserved and the 2" added to the rear.