Sandvik’s RR880 line represents a new range of pilot bits for raise boring, offering a new design to increase bit life and productivity, and reduce cost per meter. As the company pointed out, most raise boring applications begin with the drilling of a pilot hole.
The general length of a pilot hole varies from 30 to 1000 m, with standard drill pipes of 1.5 m length. The time and cost involved in pulling the pipes out from a deep pilot hole is significant and the service life of pilot bits is therefore crucial when it comes to controlling costs and time for any raise boring project. One of the main reasons for changing bits in the hole is gage wear. Consequently, in order to extend the service life of the pilot bits, much of the development work Sandvik conducted for the new bit design was focused on improving gage protection. The new Sandvik RR880 premium pilot bits provide both durability and hole straightness and up to 35% longer bit life than its predecessor, substantially reducing the time and cost for changing tools.