OnGrade Manual - Ditch Witch

Conduct OnGrade Bore - 36Drill-ThruDrill-thru mode on the tracker provides left/rightguidance information as well as pitch information.Depth information provided when using drill-thrumode can be ignored when conducting anOnGrade bore.OnGrade Operator’s ManualCorrect Depth1 2 3 4 5IMPORTANT: See tracker manual for additionaldrill-thru mode instructions.1. Stretch a string on the ground surface alongthe bore path (2).2. Place tracker ahead of the front of the drille14om014t.epshead between the drilling unit (1) and laser (5)with the center line of the tube holding the outer pods directly over the string and the left pod (3) towardthe drilling unit.3. Use left/right information to steer drill head and monitor pitch information closely.The tracker must remain in front of the drill head and turned sideways with the left pod toward the drillingunit. The center line of the tube holding the outer pods should be directly over the desired line of the bore.Correct DepthCorrecting depth gradually is critical to the success of a grade bore.Downhill or Downgrade BoreIf the measured depth from the laser plane to the beacon ever starts to become deeper than the targetdepth, the driller should drill at a pitch slightly flatter than the the target grade until the grade of the borenaturally catches up with the fall of the target grade.IMPORTANT: Do not drill at a positive pitch to correct depth. This will create a dip in the bore path.Uphill or Upgrade BoreIf the measured depth from the laser plane to the beacon ever starts to become shallower than the targetdepth, the driller should drill at a pitch slightly flatter than the the target grade until the grade of the borenaturally catches up with the rise of the target grade.IMPORTANT: Do not drill at a negative pitch to correct depth. This will create a hump in the bore path.CMW