Friction Bolt

 

Physical Properties
 

33mm Bolt
Yield Strength410MPa31kN
Ultimate Tensile Strength of Tube520MPa105kN
Friction Bolt Diameter33mm
Hole Diameter Range33.75 ± 0.75mm
Mass per Metre1.5kg

 

 

39mm Bolt
Yield Strength410MPa26kN
Ultimate Tensile Strength of Tube520MPa112kN
Friction Bolt Diameter39mm
Hole Diameter Range39.5 ± 0.75mm
Mass per Metre1.75kg

 

 

46mm Bolt
Yield Strength410MPa136kN
Ultimate Tensile Strength of Tube520MPa152kN
Friction Bolt Diameter46mm
Hole Diameter Range46 ± 0.75mm
Mass per Metre2.839kg

 

 

 

General Features

  • The DSI South Africa Friction Bolt is manufactured from high strength steel tube which has a slot along its entire length. A ring, or collar, is welded on the outer end to hold a domed plate to the rock surface.
  • The 33mm & 39mm Friction Bolt is suitable for installation with hand held rock drills (stopers/drifters). The 46mm Friction Bolt is NOT suitable for installation with hand held rock drills (stopers/drifters).
  • Friction bolts can be load tested by fitting a special ring to the bolt prior to its installation. Pull tests can then be conducted with a hollow ram hydraulic jack.
  • Further corrosion protection can be provided by hot dip galvanizing.

Installation Guidelines

  • The hole length should be longer than the bolt, nominally 150mm, to allow for any rock fretting during installation.
  • The friction bolt is inserted into the hole. The driving dolly is fitted into the rock drill’s chuck and then the bolt (with accessories) is placed onto the dolly.
  • Using full percussion and thrust the bolt is fully driven into the hole until the domed plate is firmly against the rock surface. Care should be taken to ensure the rock drill’s feed/thrust is in the same orientation as the hole or the bolt may be bent during installation.