Abstract: A universal mounting structure for changing attachments on a construction machine includes first and second ear plates mounted disposed in spaced relation. The ear plates include a first and second pair portions of elongated cutout patterns. First and second collar/pin assembly each includes a pin and a pair of collars. Each collar has an eccentric bore configured to removably receive each end of a pin and each collar has surfaces engaging complementary surfaces of one of the first or second pair portions of the elongated cutout patterns. The first and second collar/pin assemblies are configured such that a center distance between the pins can be adjusted 1) in large increments by moving either one or both of the first and second collar/pin assemblies within the respective pair portion of the elongated cutout patterns, and 2) in small increments by axial rotation of a pair of collars about a respective pin of one or both of the collar/pin assemblies.