Mounting of cutters. SANDVIK Raise Boring Heads

Raise Boring Heads are used for drilling large holes in rock. They are available in different types, including integral, segmented and extendable heads. They are designed for drilling ore passes, ventilation raises, penstocks etc., and also for civil construction applications such as cable tunnels, escape tunnels, and sewage tunnels. Sandvik reaming heads are designed with bolted components for improved flexibility and ease of service and assembly. This manual provides instructions on how to mount, maintain and operate the Raise Boring Heads.

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Key features

Integral, segmented and extendable heads
Bolted components for flexibility
Different centre hole sizes for stems
Gauge saddle system for diameter reduction
Cutter positioning for different spacing
Wear pad replacement
Re-greasing of cutters
Seal replacement

Frequently asked questions

The manual describes four raise boring methods: raise boring, horizontal boring, blind boring, and down boring with a pre-drilled pilot hole. Each method has different applications and requirements, such as access points, diameter range, and drill pipe tension or compression.

The maximum recommended cutter load is 27 tonnes and the maximum recommended reaming head speed varies depending on the diameter. You should choose the net cutter load and speed based on the machine/drill pipe capacity and rock characteristics, using the fastest RPM the rock formation allows while maintaining the optimum cutter load for maximum rate of penetration.

The saddles are located in specific positions marked on the side of the head frame. They are secured using bolts, nuts, and Nord-lock washers. The tightening procedure requires a specific torque value and the use of new bolts and nuts, even during reassembly.

Different saddle types are used depending on positioning and the reaming head type. The most frequent dressings are shown in the illustration, and their part numbers are 7008-2XXX. The number of each type varies with the reaming head diameter and type.

Replace the wear pads when the diameter D is less than the maximum value specified in the table. The replacement involves grinding away the welding joint, preheating the area, fixing the pads with clamps, tack welding, filling welding points, and checking the diameter. If necessary, grind the peeks using a silicon carbide grinding wheel.