The Black part of reducer is a modified Delta 5'' inside, to 4'' outside reducer. The 5'' part was cut off, and the 4'' end was shortened. The transparent 5'' part is made from 1/4'' plastic rings. The diameter of each ring is slightly smaller than the next in order to insure a tight fit. To make the rings, the plastic was cut into squares, and the holes cut with a fly cutter on the drill press. Machine screws are used to align each square during assembly and glue-up. A band saw was used to remove excess plastic to produce the round fitting.
