Stainless Expansion Bolt with Fixed Hanger
Note: It is the considered opinion of Safer Cliffs Australia that glue-in bolts should be favoured over expansion bolts unless there is a compelling case otherwise.
Expansion bolts are easy to place, strong and readily available. Mechanical bolts work by either expanding of compressing - gripping the rock by pressing against the wall of the bolt hole. The pressing action creates friction between the anchor and the rock; for the bolt to pull out, the applied load has to overpower this coefficient of friction.
Expansion bolts are expensive as a unit as you have to purchase a commercial hanger on top of the expensive bolt. If you are only placing a few bolts then expansion anchors are the best place to start as the cost outlay for tools is very small compared to glue in anchors.
- Pro: You can use them immediately after placing
- Pro: Almost fool proof to place
- Pro: Less tools to buy
- Pro: Hanger is replaceable
- Pro : Likely to show signs of working loose if in marginal placement
- Con: Bolt and hanger deforms after repeated falls
- Con: Hanger can be stolen and bolt tampered with
- Con: Bolt can loosen
Rust can occur when two grades of stainless (i.e. bolt
& hanger) are forced together
Recommended brands/models for medium to hard rock only:
Ramset 12mmx75mm SS Hex-Head Dynabolt DP12075HSS
Powers Flush Head Sleeve 12mm SS FHS1275SS
Powers Power-Bolt Anchor 12mm SS RBHM1370SS
Fixe 12mmx75mm Triplex SS Expansion
Hilti 12mmx102mm SS HSL-G-R
Recommended brands/models for hard rock (granite)
Ramset 10mmx65mm SS Trubolt T10065SS
Powers Through Bolt 10mmx50mm SBA1050SS