- The portion of the drill string that cannot be rotated or moved vertically.
- Causing and removing: Plumbing is hard work. Pipes heat up and cool down and are inherently wet, which leads to corrosion, which causes stuck pipe joints. Rather than grab a bigger hammer or a hacksaw and risk causing more damage, approach the situation calmly and apply logic. Cast iron and steel pipe has threaded joints, which will turn loose if you can twist them. Copper and PVC pipes have permanently soldered and chemically glued joints that must be cut out and worked around.