If others are having this problem and need more detailed instruction for making the adjustment, he will be glad to send instructions and diagrams for publication. Contact Jim Dast, 1910 Keyes Ave., Madison, WI 53711. His phone (not sure if it is daytime or evening phone) is 608/263-5480.
The cases come in any size desired, but are usually ordered in 6" increments starting with 12". They can be cubes or rectangular boxes. A 24" cube is $380; cost goes down with quantity. Ultraviolet-resisting acrylic sends the price up by 50-70%. The cases are designed for the exhibition of books, manuscripts and art Objects.