The "nested pipe" project is an attempt to catalog which pipes have a close-fit when nesting inside
each other, and which pipes have a close-fit when wrapping around a bolt.

The pipes being listed here are ones that are commonly available in hardware stores:

    - PVC pipe  [plumbing]
    - ABS pipe   [plumbing]
    - copper tubing   [plumbing]
    - conduit       [electrical]
    - 


This project seeks to resolve the problem that the ID and OD of these pipes is often completely
independent of the advertised size -- a '1/2" pipe' often has NO dimensions that are 0.5".