Rock Bolts – Bolt Fittings
- The DSI Anti-Friction Washer was developed to reduce friction between the nut and the dome ball. This, in turn, allows for more efficient pre-loading of the bolt.
- The introduction of colour coded anti-friction washers is due to the need to adequately identify rock bolt lengths, especially for mines using various bolt lengths.
- The increased diameter of washers is to facilitate ease of identification.
- A white washer is available for bolts outside the standard range of bolts.
- DSI Anti-friction washers are to be treated as part of a complete DSI bolt assembly, substitution of any component in the assembly may affect the results provided by DSI.
- It is important that correct rock bolting installation techniques are applied to prevent excessive friction between rock bolt components occurring.
- DSI anti-friction washers are primarily polyethylene which has a flash point temperature of 380oC.
- DSI friction washers can be supplied in fire retardant nylon (BWR) or Teflon.
- Customers considering Teflon washers are advised to seek assistance from a DSI technical service representative, to compare the many factors affecting bolting performance or various washers.