Drift Indicator System

Accurate, dependable drift indicator system assures vertical holes

For accurate measurement of deviation from vertical in wellbores, the Forum Drift Indicator System is the most reliable and easy-to-use drift indicator available. This essential tool enables the driller to maintain a controlled, absolutely vertical drill path.

System components include:

  • Double Recorder — Measures and records hole inclination. Consists of an Angle Indicator and a Timing Device enclosed in a stainless steel case.
  • Go-Devil — Protects the Double Recorder from shock, pressure, and fluid.
  • Various other tools and components, such as rope sockets and Go-Devil sinker weights and stabilizers.
  • Tools for maintaining the Double Recorder.



  • Instruments and charts available in 0-7º, 8º, 14º, and 16º values
  • Go-Devil available in 1-5/16 and 1-5/8-inch outer diameter
  • Variety of Go-Devil assemblies available for various methods of running the tool, including free-dropping, sand-lines, and core barrel adapters
  • Standard unit operates in wellbores up to 350º F ( 93º C )
  • Hot Well unit operates in wellbores up to 500º F ( 260º C )


  • Easy to operate — any member of the crew can read measurement data.
  • Completely mechanical system — requires no liquid or electrical equipment.
  • Reliable, accurate measurement — helps prevent costly deviations from the vertical path.