I have a need to convert a 4 inch dust collection system to a smaller
1 1/2 inch connector on a belt & disk sanding station. Is the standard
size for 2 1/2 pipe, a inside or outside diameter? If it usually a
outside diameter, what is the usual inside measurements? If I purchase
2 1/2 inch flexible pipe where can I find the correct fittings to mate
the 2 1/2 inch pipe to the 1 1/2 in connector on the sander?