Ditch Witch OnGrade - Manual (Page 44)

OnGrade Operator’s Manual
Systems and Equipment - 43
Downhole Tools
CMW
• Grade transition sub: is stiffer than standard
transition subs and helps maintain a straight
bore path. Reduces the drill head’s tendency
to deviate from a straight line.
Backream
Tools
• Flail backreamer: provides very thorough
mixing action to create a flowable soil slurry
and has support wings to help maintain the
vertical position of the reamer in the bore hole
in softer soils.
• Centering tools: are placed in front of the
backreamer on second and third backreaming
passes to help hold the reamer in the center of
the bore hole. This helps reduce the tendancy
of the reamer to lower the bore hole on
subsequent backreaming passes.
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