Archive for the ‘Glossary’ Category

Concrete Cutters Glossary Part 6

Monday, September 14th, 2009

Power Tools
Used widely in the construction industry, power tools are powered by electric motors, petrol or diesel or via a compressed air motor. There are two classifications of power tools, either stationary or hand-held ‘portables’. Stationary tools are known for their speed of operation and power. Portable tools can also be battery operated. Their main advantages are their ease of use in confined spaces and their relatively lower cost. One of the downsides to using power tools is the vibration and noise produced during their operation.

Diamond Blades
Often used in circular saws, diamond blades are made from a steel core, powdered metal compounds and diamond crystals. These crystals are bonded to the blade by the process of heating and pressing into a moulding creating the diamond ’segments’.  These segments make up the blades cutting teeth. This blade is then welded to the steel core.

Other methods of manufacture include electroplating diamond crystals directly to the core metal plate. Sometimes other metals are used instead of steel and other methods may be used depending on the intended application. Some cores have gullets, effectively spaces, between the segments to allow for cooling and the removal of slurry. Others have a single continuous rim to allow smooth cuts to be made without chipping the material being cut.

Diamond blades are used for circular saws used primarily when cutting abrasive or hard surfaces such as those found in the construction industry during building works. When used in band or chain saws the blades are ideal for creating controlled shapes.

Instead of cutting, diamond blades grind down the surface using their rectangular segments or teeth. These teeth contain diamond crystals on their tips enabling them to grind through even the hardest of materials. The choice of bonding compound effects the rate of wear and the life of the blade. Softer bonds will wear down more quickly, exposing new diamond segments to ensure the edge stays sharp. This makes the choice of bond of paramount importance, it must be tailored to the specific material you need to work to be economical.

Water can be used to prevent overheating and improve efficiency, however this cannot be used on electrical saws. The diamond blades are unable to cut ceramic or abrasive materials if the temperature is not controlled sufficiently. Using water creates the optimal cutting environment and extends blade life significantly.

Water can also be used to remove the slurry from the cutting area and reduces the dust generated. This dust would pose a serious health risk to the operator and anyone working nearby. If using dry cutting blades they must be periodically cooled by allowing the blade to operate without cutting the material ‘in air’. The air flow will then pass over the blade’s segments reducing the surface temperatures.

Concrete Cutting Projects
Projects where concrete cutters are used include; building works, demolition, conduits for services or pipes, civil engineering works, road sawing, expansion joint cutting, installing concrete fixings, creating openings for lifts, stairwells, doorways, windows and many others.

Under Reaming
Under reaming is used where securely anchoring equipment or fixings is of paramount importance. The process is used to create grooved slots into holes that can be used for securing anchor bolts, masts, and starter bars. Applications include rail anchor bolts, heavy industrial machinery fixing and telephone mast bolting.

Concrete Cutters Glossary Part 5

Thursday, September 10th, 2009

Floor Chasing
Where there is a requirement to create floor chasing, tradesmen often use more powerful saws that are dedicated to this application. The extra power makes larger volumes of work easier. These units are petrol or electrically powered, some are twin bladed and others more portable.

The twin bladed units allow two parallel cuts to be made simultaneously. Once the channels have been cut, the remaining material can be removed by percussive or manual methods to minimise disruption. Using hand held or semi automated concrete saws is an economical way for chasing into concrete, masonry or asphalt, ideal for creating expansion joints.

Wall Sawing
Track mounted diamond blade saws can be used to produce vertical and horizontal cuts in concrete, even on steep inclined surfaces where a slab saw could not safely be used. Wall sawing  techniques provide a cheap efficient method for cutting openings for ventilation units, doorways and windows, plus bevel cutting and other specialised applications such as finishing roughed walls. The edges created by wall sawing are straight and smooth and sized within a good tolerance creating fixture ready openings.

Wall Chasing
Wall chasing is a method often used when working on structures that are occupied. An industrial vacuum is used to collect dust before it contaminates the surrounding area. Reinforced concrete walls and brickwork can have neat channels with depths of 40 mm cut into them fairly quickly. Ideal for many retail, industrial and commercial applications such as factories, offices, surgeries, hospitals, retail premises, hotels and anywhere else where cabling or piping installation is required.

Diamond Tools
Diamond Cutting Tools are used to cut through many non-ferrous materials. The blades of these powerful cutting machines have diamond crystal segments bonded to a powdered metal base material. This gives them the strength to perform their task without the constant need to replace the cutting tool’s blades.

This bond is one of the prime factors to be considered when selecting which cutting tool to use for a particular material. The hardness of the target material along with the abrasiveness and the bond of the cutting tool’s blade will determine how quickly the metallic powder will wear down.

As the powder wears, more diamond crystal segments are exposed on the surface to ensure the cutting edge remains sharp. Iron and steel are not suitable for cutting with diamond tipped cutters as the carbon would be dissolved into the surface of the object being cut leading to hardening causing excessive tool wear. There are alternatives for cutting Iron and Steel based surfaces; these are generally hard metal compounds such as Aluminium Oxide, Silicon Nitride and  Cubic Boron Nitride.

Diamond tools are designed to cut highly abrasive materials such as ceramics. When sawing or grinding though hard materials a diamond blade with a soft bond is required. The diamonds themselves are either natural industrial diamonds or may have been synthetically manufactured.

The diamonds themselves are classified by various shapes and grain sizes. During cutting, the metal powders bonded within the cutting blade’s teeth wear down. Thus exposing newer diamond crystals and maintaining an efficient cutting edge. If you are cutting a softer abrasive material e.g. freshly poured concrete or asphalt, a diamond blade with a harder bond would be selected as it’s segments do not wear down as quickly, making this the preferred economical choice.

Concrete Cutters Glossary Part 4

Monday, September 7th, 2009

Floor Sawing and Cutting
Floor sawing and cutting or ’slab sawing’ is an efficient method used to cut info flat surfaces such as roads.  Concrete floor diamond cutting machinery can saw over half a meter deep depending on the saw used. Slab sawing eliminates the need for the use of noisy jack hammering equipment. Applications include road and motorway maintenance work such as expansion joints, whether concrete or asphalt, floor slabs, pavements and bridge repair work. Reinforced concrete can also be cut successfully. A self propelled sawing unit usually powered by diesel engine can be used outdoors or a three phase electrically powered unit can be used in restricted areas such as warehouses containing food. Another advantage of slab sawing a flat surface as opposed to jack hammering, is the reduction in the amount of dust generated, allowing easier clean up and removal of the site.

Concrete Floor Grinding
Diamond floor grinding machines can be used to level uneven floor surfaces by eliminating high spots. If left in situ, these high spots may become hazards and could require costly removal at a later stage.

Selective Demolition
Buildings and structures can entirely or partially demolished using various cutting and drilling techniques, without risking damage to surrounding buildings and structures.

Hydraulic Crunching
Hydraulic Crunching is a method used for heavy demolition tasks converting concrete into waste rubble. Hydraulic crunching has revolutionised the way many demolitions are performed, in many cases it has replaced the noisier and potentially damaging jack hammer. The jaws of the machine are applied to an edge of  the concrete structure which can be up to 310 mm thick. Hydraulic power is used to close the jaws and literally crush the structure, this is repeated until the whole structure has been destroyed.  This is a non percussive technique and as such generates little noise, vibration or dust. Water is not required for dust control. Hydraulic crunching can be used internally or externally and can remove the concrete leaving the reinforcing material to allow remedial work to be performed.

Hydraulic crunching is also used to make economies when disposing of waste material such as concrete and masonry created during the construction process. After material has been cut out using various saws and drills it is often in large chunks, these take up significant amounts of space quickly filling up skips or tipper trucks.

Expanding Grouts
Expanding grouts can be deployed to enable reinforced concrete, rock or stone structure to be blasted and cracked without using special equipment. The process uses chemical powder that can be mixed with water and packed into pre drilled 40 mm holes in the target structure. The grout can therefore be used very accurately to emit a localised cracking pressure within the structure. This method of performing a concrete demolition is quiet and generates little dust.

Anchor Fixing
Rotary percussion techniques are employed to perform anchor fixing. Horizontal or vertical diamond drilling into reinforced concrete, masonry blocks or walls slabs facilitates the fixing of plates, expanding anchor bolts, metal cleats or cladding panels.

Demolition
In larger demolition projects such as bridges, foundations or pavements, boom mounted or hand held pneumatic or hydraulic breakers can be utilised. Concrete strength, hammer size and the quantity of steel reinforcements along with working conditions are factors to be considered when performing such a demolition. To reduce the demolition’s impact on the surrounding environment segments of concrete can be safely removed by crane, keeping noise and dust levels to a minimum.

Concrete Cutters Glossary Part 3

Friday, September 4th, 2009

Hand-held Saws
Hand-held ring and chain saws are convenient when cutting floors areas inaccessible to road saws and for shallower depths are a more efficient way of cutting  that by using a wall saw. Water sawing techniques help prevent dust contamination to the surrounding areas. Applications where these type of saws can be utilised are for plumbing, electrical cabling, heating, ventilation, air conditioning (HVAC) openings, crawl spaces and basement trenching.

Floor, Slab and Curve Sawing

Concrete floor diamond cutters are frequently used to cut flat surfaces such as roads, runways, bridges, pavements and reinforced slabs. Cuts over 500 mm are possible using the self propelled machines. Three phase electric saws can be used instead of diesel powered units to carry out work in restricted areas such as food preparation warehouses. Asphalt and concrete surfaces can be cut using this machinery. Curb sawing is used to create or enlarge wheelchair ramps, driveway approaches and foundation curbs. Curb saws also use a diamond tipped circular blade allowing any length of curb stone to be tackled.

Wire and Plunge Sawing

Wire and plug sawing allows almost any thickness of concrete, granite or stone to be cut through. Suitable for mass and reinforced concrete this innovative technique almost silently creates a 12 mm width cut, ideal for cutting deep slabs, beams and bases. Plunge sawing is commonly used when constructing reinforced columns, bridges and viaducts.  A diamond coated loop is used to encompass the object to be cut. This wire loop forms the blade and can be of almost unlimited length. Hydraulic power and pulley systems drive the saw ‘blade’ through the object. A water system is employed for temperature control of the blade. This process can also be used on steel and when access for conventional sawing machines is limited.

Diamond Wire Sawing
Since the 1980s, diamond wire saws have been used to cut concrete of almost any thickness making them extremely useful for heavy demolition work such as bridges, columns, piers, damns or any other thick concrete structures. They can cut various sized openings such as columns, round holes, bases for any structure or even entire structures themselves. They can even be used under water! Diamond wire saws are the evolution of the original wire saws used in the stone quarry industry. The wire saws blade comprises continuous loop wires with bonded diamond segments. In operation, diamond wire saws create minimal vibration, noise or dust allowing them to be used even in inhabited or hazardous locations. They are adept at creating straight or architectural cuts.

Concrete Channel Chasing
Hand held electric grinders can be used to create neat channels within concrete or masonry structures. The grinder uses a diamond blade to make the cut, and a vacuum system is employed to gather the dust generated. The vacuum system prevents dust from contaminating the surrounding environment including other trade people working nearby. These chases can be used for housing conduits and pipes in ceilings, walls and floors. Channel chasing equipment is often used by electrical and mechanical traders when installing pipes and cabling.  Two precision slot cuts are made using the cutting tool to a predetermined depth. Allowing a light weight hand held hammer drill or small breaker access to remove the concrete in between the cuts.

Stitch Drilling
A technique called ’stitch drilling’ can be utilised to create overlapping drilled holes that enable complex apertures and curves to be cut from the source material. Stitch drilling is mainly used for channelling out larger or unusual shaped openings whilst leaving the surrounding areas unscathed.

Concrete Cutters Glossary Part 2

Tuesday, September 1st, 2009

Diamond Track Sawing
Diamond Track sawing is also known as ‘Masonry Wall Cutting’ or  more commonly just plain ‘Track Sawing’. This construction technique is utilised to make precise cuts into reinforced concrete or masonry walls, floors, columns or beams. This is often used to cut out window openings and doorway sections, to reduce the height of existing walls or even create the large openings required for stair wells and lift shafts. These powerful cutting machines are powered by diesel, petrol or electricity. Track mounted walls saws can be used to cut precise channels over 600 mm, or even over 750 mm, in depth, leaving a clean edge for the building work to continue efficiently.

Diamond Track Sawing Operation
Wall cutting machines can be setup almost anywhere using easily assembled components. A track is securely mounted on the source concrete or masonry wall to be cut. The saw blade is attached to the machine head and this is rotated at high speed to perform the cut in small increments, along the length of the track. To reach the required depth of cut a series of adjustments are made by the operator.  This allows the correct cut to be made without additional straining or stress on either the equipment or structure being worked. Track saws can be remotely monitored by the operator using a remote device, this helps maintain a safe working environment. As well as conventional straight cuts, concrete cutting machinery can also create angled, flush or inverted cuts. Using a flush cut adapter, square cuts can be made from adjacent walls, these cuts are made to within a 2 mm tolerance.

Concrete and Masonry Wall Diamond Cutting
Concrete and masonry wall diamond cutting or ‘Track sawing’ is an effective way for cutting precision openings for doorways and windows or reducing wall height. Other uses of this technique are to cut apertures in concrete for stair well and lift shafts.

Diamond Wire Cutting
Almost any large, thick concrete or masonry structures can be cut using the diamond wire cutting method. Even reinforced concrete used in damns, bridges, columns and concrete situated underwater can be tackled successfully.

Ring and Chain Sawing
Ring and Chain Sawing are quick and efficient ways to cut into concrete, granite, brick breeze blocks, reinforced steel bars. The diamond tipped blades allow even the strongest materials to be tackled. Hand held chain saws can cut up to 1m deep, ideal for making straight cuts whilst minimising the risk of over-cutting. Also useful when shaping blocks of material. Ring Saws can cut up to 2.5m deep. These methods can be used to create windows and doorways, expansion joints, ideal for use in areas where access is limited. Other similar cutters can be used to make square corners.

Chain and Ring Sawing
Chain and Ring saws are ideal for producing clean corners and straight lines in hard materials such as concrete, granite, breeze blocks and cutting heavy duty steel bars. Ring saws can make cuts of up to 250 mm deep through these materials. Hand held ring saws are the preferred choice in areas where access is limited and are suitable for tackling structures that are made from reinforced materials. They can be used for cutting smaller apertures such as windows and door openings. Chain saws can cut up to a meter deep.

Concrete Cutters Glossary Part 1

Monday, August 3rd, 2009

Welcome to part 1 of our 6 part concrete cutters glossary. Over the next 2 weeks we will be issuing 6 total glossary entries, with the intent of describing all the of the key terms used in concrete cutting. Please keep checking back as these points will be handy for any one, intending to buy a concrete cutter, to know.

Concrete Saws
Concrete Saws often referred to as ‘consaws’ or ‘road saws’ are power tools used for cutting masonry, asphalt, brick, tile and most other solid materials. Concrete saws can be powered by hydraulic pressure, diesel, petrol or electric motors1. As significant heat is generated by the friction occurring when cutting hard substances such as concrete, the cutting blades require significant cooling to prolong their life span. Water is often used to cool the blades and reduce dust contamination. The blades themselves have either diamond or abrasive tips.

Circular Saws
A circular saw should be used for cutting other materials such as wood, plastic and some masonry. Similarly to concrete saws they have teeth bonded to a metal disc or blade which is rotated at high speed to make cuts or slots. Circular saws may be table mounted or hand-held. Most units are powered by electric motors.

Diamond Drilling and Core Drilling
Diamond drilling is an efficient method of making precise, circular cuts within strong substances such as reinforced concrete, granite, stone and brick. This drilling method utilises a non vibrating, dust free and relatively quiet drill, enabling precise cuts to be made. As these cuts are so accurately made they result in clean sided holes, reducing the need for additional finishing. Water is used as a coolant to ensure dust generated during the cut is kept to a minimum, allowing work to be performed even in occupied buildings. Diamond Drills often have a built in water feed through the drive shaft for this purpose. Other materials such as thin steel plate and cast iron and can also be cut using this method.

Power is provided by hydraulics or electric power units. From small holes of as little as 10 mm in diameter to larger holes over one meter in diameter, with nearly unlimited depths, diamond drilling is the most efficient way to create precise apertures. Barrel extension sections can be used to increase the drill depth. Dry drilling of holes up to 100 mm is usually feasible, this is useful when working in areas containing existing electrical installations for example, where water cannot be used safely. As this method of drilling materials such as concrete is so quick and efficient, it ensures labour costs and kept to a minimum for any works.

By using remote cutting machinery even confined spaces can be worked. Drilling machines have diamond segmented drill bits mounted on the rotating ends of their cutters. These machines can operate vertically and horizontally and in inverted positions when using them in confined areas.

Line Drilling
Line drilling is a technique where multiple core drills are made to create a series of overlapping holes. These holes allow a large segment of concrete to be removed leaving the surrounding material unaffected. Line drilling is an extremely effective way to remove almost any thickness of concrete and is useful when creating unusually shaped openings or larger apertures. Some examples of applications where this method of drilling could be used are; when installing electrical, fibre and telephone cabling openings, sewer and floor drains, tie-ins, heating, ventilation, air conditioning (HVAC) openings, for aggregate analysis or any floor, wall or roof penetrations.

Core Drilling
Core drilling is used to perform precise circular cuts of up to one meter in diameter. Core Drilling is often used to create openings in reinforced concrete suitable for plumbing, electrical cabling, heating, ventilation, air conditioning (HVAC) installations.