Abstract: A pipe assembly used in horizontal directional drilling operations. The pipe assembly has an outer member, an inner member, and first removable collar. The inner member has a polygonal outer profile of uniform shape along its length and is partially contained within the outer member. The first removable collar is supported on the inner member within the outer member and limits relative axial movement of the inner member and the outer member.

Abstract: An apparatus used to excavate trenches. In a preferred embodiment the trenching machine has a cutting disc supported on a frame and adapted to operate with the center point of the cutting disc below ground. A spoils handler supported above the cutting disc and forward of the center point is used to move spoils away from the cutting disc. The ratio of cutting depth to weight of the trenching assembly and the cutting depth to wheel diameter is improved through the use of a cutting disc that is concave. The outer rim of the concave disc may support a plurality of replaceable cutting member. The cutting disc is rotated using a drive assembly that is contained within the cutting width of the cutting disc.