waverlyj Posted July 21, 2009 Report Share Posted July 21, 2009 NRG offers rock anchors in 3 sizes: 15" 30" 53" These anchors are 1.75" and the widest part and need a 2" diameter pilot hole drilled at least 6 inches less than the length of the anchor (the length measurement includes the eye that the guy wires are run through - this will keep the eye above ground level): For the 15", drill 2" diameter a hole 8" - 9" down. For the 30", drill a 2" diameter hole 23" - 24" down. For the 53", drill a 2" diameter hole 46" - 47" down. It is a good idea to tape the expanding end of anchor before trying to insert the anchor into the hole to test to see if it is drilled to the correct length. This keeps the end from expanding and becoming stuck in the hole before you are ready for it to be expanded: When ready to expand the rock anchor, remove the tape, insert the anchor until it hits the bottom of the pilot hole, and twist clockwise by inserting a rockbar or piece of rebar into the eye of the anchor. Turn until you feel the anchor start to slightly bend - STOP IMMEDIATELY and align anchor eye horizontally to the ground. Link to comment Share on other sites More sharing options...
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