Small Boring Unit (SBU)

Typical Small Boring Applications:

Small Boring Unit (SBU) extends the capabilities of the standard Auger Boring Machine and is typically used on underground utility installations, such as gravity sewers, that are between 100 and 300 ft in length. However, the machine has been used successfully on drives over 500 feet.


Small Boring Unit (SBU) is a auger-boring technology that can easily cut hard rock faster in small diameter drives than any other method available. SBU (Small Boring Unit) is a small diameter cutter head and thrust bearing assembly (from 24 in / 600 mm to 72 in /1.8 m) that can be used with any auger boring machine (ABM) from 36 in (900 mm) to 72 in (1.8 m).

It is the most time and cost effective way to bore through hard rock, cobbles, caliche and river run.
Although SBUs have been in use for over 10 years on hundreds of projects around the world, SSC Boring is the first to offer this technology in Arizona and is the leading Auger Boring machine company in Phoenix!


Range in diameters from 24 to 72 inches.


  • These are the same types of cutters as used in larger hard rock Tunnel Boring Machines (TBMs), only they are used in smaller diameters (6.5, 9.5, or 11.5” depending on the SBU diameter)
  • The disc cutter excavates rock from 4,000 to over 25,000 psi UCS by creating a “crush zone” through which fractures propagate until the material between adjacent crush zones is chipped from the rock face.
  • SBUs are operated by welding the lead steel casing to the head. The Auger Boring Machine generates torque to rotate the SBU, while forward thrust is provided through the steel casing. Muck scrapers scoop the muck from the face into openings on the cutterhead, which convey it to a full-face auger for removal.

If your gravity sewer installation project requires the need of a small boring unit to be used on the underground utility construction then please contact our local small boring company and let our experts provide the right solution for your auger boring machine needs.