DRILLING AND SAWING ASSOCIATION

Rotary Percussive Drilling

This is the basic method of drilling construction materials using a hand-held drill and is suitable for most hard un-reinforced materials. It can be used for small diameter holes i.e. for rawlplugs 4mm up to 75mm rock drills and over. In the diamond drilling industry it is normal for all operatives to carry a Kango or Hilti type of 110 volt rotary percussive drill/hammer to enaable them to carry out simple cutting and fixing operations i.e. drilling brick or concrete to enable adequate bolting down of drilling plant or track sawing equipment. Also used to break out concrete for removal, as well as forming chases for conduits or pipes.

Diamond Drilling
General Drilling Rigs - Diamond drilling rigs can vary in design but the basic principal is the same. The base plate of the drill stand is secured to the concrete/brick to be drilled either by rawlbolt, acrow prop, vacuum pad or weights.

The power unit is either electric, hydraulic or air. Drilling bits start at 10mm and can go to as large as 1 metre or more. Drilling depths are virtually unlimited using barrel extensions.

The smaller the diameter, the greater the speed of rotation, and except for a few special types, all have a water feed through the driving shaft, to keep the diamonds cool, the cutting free of grit, and generally assist in reducing wear. Water also totally eliminates dust.

This technique is used when precise circular cuts are needed, to create openings for example, for plumbing, electrical and heating/ventilation installations. Core drilling is commonly used to create the holes for routing cables or for placing anchor bolts, for installing load carrying devices or for concrete sample analysis.

A core drill bit consists of a steel tube with diamond segments brazed or welded on the drilling end, and mounted on a rotating shaft. Core drill machines can be operated in either vertical or horizontal direction and can be powered by electric, hydraulic or air sources.

Trailer Rigs
A drill rig unit can also be fitted to a mobile two-wheel trailer to form a specialist trailer drilling rig capable of being towed behind a van or car. These drilling rigs are used for specialist operations such as core sampling and installation of motorway barriers etc.