Epoxy Resin Being Injected To A Drill Hole To Secure A Glue-In Anchor

Installation of Anchors & Bolts


Selecting the correct anchor type, material choice and ensuring the anchors are fabricated via a quality manufacturing process is just the start of a reliable fixing.

Installation must follow correct procedure and the information below provides an introductory guide. Seeking formal training or mentoring from an experienced bolter is strongly recommended.

Rock Quality

Visual inspection – The anchor location must be in solid rock, away from fractures, too close to edges and definitely not in entirely detached blocks. This requires a macro view of what you’re drilling into aswell as a micro view of the host material.

Impact assessment – Using a suitably weighted hammer (wall hammers ideal) tap the rock around the intended anchor location and listen for a solid ringing sound. Anchors should not be placed into hollow sounding rock.

Mechanical Bolts

  1. Ensure you are using the correct drill bit diameter and length – this is crucial for expansion bolts.
  2. Ensure the location is as flat as possible upon which the hanger will sit.
  3. Drill the bolt hole at right angles to the rock surface AND over-drill the hole to enable the stud to be hammered into the rock and patched in later years if needed.
  4. Confirm the hanger will sit flat; otherwise, chisel the rock flat (only) in the area surrounding the hole and beneath the hanger profile.
  5. Blow the hole free of dust. This is to prevent the clip or sleeves from jamming before tightening.
  6. Tap the expansion bolt assembly (including the hanger attached) into the hole with the nut threaded down just below the end of the shaft so as not to damage the threads.
  7. Once hammered in, unscrew the nut slightly to enable the last few millimetres of the shaft to be driven into complete depth.
  8. Align the hanger in the likely direction of loading and torque the nut slightly beyond hand tight.
  9. Inspect the rock for any signs of microcracking.

Glue-In Anchors

  1. Ensure you are using the correct drill bit diameter and length.
  2. Ensure the location of the anchor won’t result in an attached karabiner being levered over an edge.
  3. Drill the hole slightly inclined (around 10 degrees up) for our twist-leg anchors and at right angles for both types of Titan Climbing anchors. This is to ensure the anchor eye will sit flush against a flat rock surface.

Titan staples require particularly skilled drilling to ensure both legs are centred in their respective holes. Use the staple leg to scratch a mark on the rock surface, drill a few millimetres, and then assess the leg positions before drilling deeper. This will enable the angling of the drill bit to re-correct hole alignment if necessary before continuing to full depth.

Important!!! – Ensuring sufficient hole depth is crucial for glue-in anchors with an interference fit for once they are tapped in, it can be difficult to twist the fixing out in the event the hole is short. The only downside to over-drilled holes is using more adhesive, and with experience, this can be ‘dialled back’.

Special note regarding notching

Whether to notch/provide a recess in the rock for the eye is often debated; however, foremost is that the EN959 certification does not require notching for the certification assessment. That said, we recommend notching/counter sinking / for larger eye glue-ins because a) it prevents a rope trap beneath the eye b) lessens the eye profile c) resists some flexing. Notching does not necessarily need to be deep to improve the profile of a glue-in and eliminate any catching of the rope beneath the eye. Note that notching can make glue-in anchor extraction harder when coring because the eye cannot be readily cut away by a cordless angle grinder.

Notching and the flex of a glue-in anchor eye is an issue for softer rock, and so counter sinking is standard practice for climbing areas such as the Blue Mountains of Australia.

Counter sinking requires careful management to ensure the notch is not so deep to recess the eye to cause karabiners to become levered (and therefore potentially snap when loaded from a leader fall).

Notching can be achieved by drilling a line of closely spaced shallow holes and breaking them through by angling the drill bit or by using a cross-head drill (as sold by us on the site) and feathering the drill speed while running the bit head up and down in a line to create a notch.

  1. Hole cleaning – this is absolutely critical. Using a hole-cleaning brush and blower, alternate between brushing and blowing the dust free of the hole until no more dust can be blown free. The number of times necessary will vary for different rock types, hole diameters and depths; however, several cycles (3 to 5) are common.
  2. Dry fit the anchor to ensure it will seat correctly and achieve full depth.
  3. Prepare the adhesive and dispenser according to the manufacturer’s instructions. Inject adhesive into the hole for at least 2/3rds of the hole. Don’t forget to release the pressure off the adhesive pack – this prevents adhesive dribbling all over the rock. Wipe the tip with a rag.
  4. Check the anchor is free from dirt or grease, then insert it into the hole, rotating the anchor to distribute adhesive around the shaft as it is inserted. Upon reaching the beginning of the inference fit it will be necessary to 'dress' the expelled adhesive into the recessed notch (if applicable).
  5. Using a NON-FEROUS hammer (rubber/wood or stainless steel), tap the anchor home, ensuring the eye is aligned in the likely direction of loading.
  6. Tidy up any excess adhesive, ensuring the base of the eye is covered on all sides. The hole and region surrounding the eye should be entirely filled with adhesive.
  7. Consider whether the anchor(s) could be unintentionally loaded by others before the adhesive has fully cured. Tape/tag the eye or attach a warning note as appropriate.