The short version
- Jack and bore pushes steel casing in a straight line
- HDD steers flexible pipe on a curved path
- Jack and bore suits gravity pipe and heavy crossings
- HDD suits long crossings and conduit
How each works
Jack and bore, also called auger boring, pushes a steel casing pipe through the ground from a launch pit while an auger inside removes the soil. The casing follows a straight line at a set grade.
HDD drills a steerable pilot hole and pulls flexible pipe back through it.
Straight vs curved
Jack and bore is straight and tightly controlled. It is the right tool when a casing must be installed to a precise grade, such as for a gravity sewer or when a regulator demands a steel casing.
HDD can curve under obstacles and drill much longer distances.
Pits and equipment
Jack and bore needs a larger launch pit with shoring and a track to push from. HDD needs smaller pits and a rig on the surface. Space, depth and access influence which one fits.
Both avoid cutting the road.
Choosing
Roads and rails with strict requirements often call for jack and bore. Long conduit and pressure pipe runs favor HDD. A designer or utility may specify the method, and we recommend based on the soil and the route.
When rock is present, either may need an alternative approach.
General information, not engineering, legal or safety advice. Rules and requirements vary by utility, city and county.
