Citi-Con’s stitch-core drilling expertise is an extension of our state-of-the-art diamond core drilling technique. It provides unrivalled precision, efficiency and adaptability for even the most challenging tasks.
We deploy stitch-core drilling to create larger or irregularly shaped opening that cannot be achieved with a single core drill. A series of overlapping holes is drilled. This “stitches” the material to achieve the desired size or shape without compromising accuracy or structural integrity.
This technique is also ideal for making wide holes in tight spaces for conduit or pipe-course placement, for example.
Stitch-core drilling – best alternative
By reducing dust, debris, noise and vibration, stitch-core drilling is the best alternative when working in restaurants, hotels and hospitals. This is in addition to commercial and industrial premises that need to remain operational during refurbishments, upgrades or retrofits. Excessive dust, noise and vibration are a severe health hazard and, therefore, must be managed appropriately. This is in line with the Occupational Health and Safety Act 85 of 1993. It is specific about the protection of workers from the harmful effects. This is achieved by maintaining a safe working environment, identifying and controlling hazards and providing information and training.
Water introduced as a coolant and lubricant directly at the drill bit cutting surface acts as a dust suppressant. This water mixes with the fine dust particles generated during drilling. It causes them to stick together and form a slurry, which can be effectively managed and collected, also ensuring a clean site. Furthermore, core-stitch drilling does not use percussive methods that generate air-borne dust. Rather, it deploys a rotary action to cut clean, cylindrical holes. This approach creates intact material cores that are easier to remove than a pile of debris which can create dust when handled.
Stitch-core drilling is efficient
Our stitch-core drilling is also flexible and efficient, saving in retrofit, repair and refurbishment time and costs.
By using compact and portable core drilling equipment, less time is spent on site establishment, particularly in confined or hard-to-access areas.
Other than basic concrete scanning to locate obstructions and hidden services, very little preparation is required.
Because it is a non-impact, low vibration method, stitch-core drilling reduces the risk of structural damage. This saves time in reinforcing the structure or undertaking repairs during and after the process. Efficient material removal also saves in cleaning time.
As an adaptable method, time is saved in switching from one technique to another.
Stitch-core drilling capabilities
We recently had the opportunity to again demonstrate the extent of our stitch-core drilling capabilities. It was deployed to create openings for the installation of two new bin silo chutes. The project is part of a silo bin complex upgrade that we are completing for a raw food materials steward.
Over 1,5t of concrete was removed to create openings in which new chutes will be installed. The largest hole is 1,2mm x 0,400mm and the other slightly smaller.
More than 48 closely spaced cores were drilled according to the engineering design to shape the openings to exact specifications. This will ensure that the chutes fit precisely.
We completed the project in only six days, using a Hilti DD 200 coring machine. Refer to DD 200 G02 Core drill – Diamond coring – Hilti South Africa. It was equipped with a 450mm x 110mm diamond-tipped barrel from Diamond Products Group [Core Bits – Diamond Products Group].
Best stitch-core drilling equipment
As a diamond core-drilling expert, we insist on only using the best stitch-core drilling equipment on our many projects. This mitigates downtime due to breakdowns.
Importantly, quality equipment facilitates accuracy. By keeping the machine stable, the risk of misaligned cuts that could potentially damage the structure is mitigated. Anchoring systems stop any shift during a job, especially important in high-risk areas near gas mains or electric lines.
However, a machine is only as good as its operator!
Extensive stitch-core drilling knowledge
The machine was expertly operated by Dion Rudolph, a seasoned Citi-Con Project Manager with extensive stitch-core drilling knowledge. Refer to News: Dion Rudolph bolsters Citi-Con’s project management capabilities.
Dion made light work of coring through the 500mm-thick concrete, extensively reinforced with high-tensile Y25 and Y32 steel reinforcing. The diamond tips were, therefore, kept well lubricated with a constant flow of water mixed with washing powder. Before encountering rebar again, the dull or glazed bits were sharpened by adding sand to the water. This enabled them to grind against the aggregate.
Considering the sheer size of the openings, the blocks were divided in half with a line of stitch-drilled holes. Rigging eyes were then installed at strategic points on the block. The isolated section was then broken out with jackhammers before carefully hoisting it out.
Extra safety precautions were also implemented. This is considering that we were working in an operational area and within close proximity of other Citi-Con employees. We installed a canvas safety barrier to prevent injuries in the event of kickback. Again, an impeccable safety track record was maintained throughout and praised by our client.