It’s all about choosing the right drill for the job and its important distinct functions, and then having the correct techniques and equipment, say the experts.
images by Vermont Sales
Certain cordless drills provide torque, speed and sometimes impact energy just like corded power tools do. Yet the drilling quality is not decided by these criteria alone. How do hammer mechanisms work? Which drilling function is suitable for which construction material? How is the type of construction material determined when drilling into a finished wall or panel?
Identifying the construction material
Construction materials are not easy to identify in a completed construction. As soon as the wall is plastered or covered, the exact construction material is difficult to identify. Conducting a test drill with a small drilling diameter is the way to remedy this situation, making it easy to determine whatever is hidden under the surface:
‘Exceptionally fine, white to gray drilling dust
Solid brick Red drilling dust
Aerated concrete Light gray, coarse-grained drilling dust
Perforated brick Hollow spaces can be felt when drilling, light red drilling dust
Plasterboard Hollow space behind the boards, fine white drilling dust
Sand-lime-brick Fine-grained, sandy white drilling dust
Cleaning the drilled hole
Cleaning the drilled hole is something that many people often underestimate: It is a key factor when installing mounting elements, since drilling dust in the drilled hole can reduce retention forces by more than 50%. Therefore, Georg von dem Bussche from Festool recommends cleaning the drilled hole before installing further mounting elements.
When drilling, the rotational movement of the drill bit guides drilling dust backwards but fitting a drilling dust nozzle considerably reduces exposure to dust for users. The solution is the dust nozzle.
“For example, our D 27-BSD drilling dust nozzle is very practical and clean. This keeps the drilled hole clean, and dowels benefit from better grip,” von dem Bussche suggests.
The right choice of drill bit is key
In addition to the hammer mechanism principle, physical force and drilling quality are primarily dependent on the choice of drill bit.
For construction materials such as plastic, and especially composites, the experts recommend special drill bits. For hardwood, chipboard, plywood or MDF boards, spiral wood drill bits are perfect. When drilling in wood, the rule of thumb is: The harder the wood and the larger the drilling diameter, the lower the speed – and vice versa.
Plastics can be worked using wood drill bits, but steel drill bits are better. For plastics, drilling must be performed particularly slowly and carefully to prevent overheating. It is therefore advisable to keep removing the drill bit and remove any chips.
Hazards can arise when drilling. Using a tool with a fitted kick back stop can reduce the risk of the drill suddenly jamming in the material, thereby minimizing the risk of twisting your wrist. Always wear ear protection and safety glasses when drilling.
Use and function of a percussion drill
The hammer action works in the axial direction for percussion drills. Here, however, the function is generated by two tooth and notch discs, which come into contact with each other and “slide” on each other.
This process transfers hammer actions to the tool chucks, which acts on the material via the drill bit. During percussion drilling, many small hammer actions act in the axial direction of the drill bit. Thanks to the notch discs, a higher stroke rate is generated than with a hammer drill, but the impact energy is lower.
A hammer drill works at a lower stroke rate, but with significantly greater impact energy than a percussion drill. This enables work to be completed more quickly. Hammer drilling in concrete requires less force than percussion drilling.
However, for softer materials/panel materials, von dem Bussche recommends working without using hammer action; such as with fibre cement panels, plasterboard, gypsum fibreboard, stone with porous joints (aerated concrete, pumice concrete) and masonry made of perforated brick.
Diggers’s expert tip
Every tradesperson knows that ease of use is necessary on the construction site. Professionals and serious DIYers appreciate it when functions and attachments can be changed quickly. I prefer the Festool united CENTROTEC tool chuck and bit holder as it is half the size and 80% lighter than comparable chucks.
It fits all Festool cordless drills and cordless percussion drills with the FastFix interface, enabling users to change tools in a matter of seconds. In addition, the TPC cordless percussion drill and the TDC cordless drill, using the electronic KickbackStop, minimise the safety hazard.
Last edition’s competition: A Tork Craft Tork Craft Angle Grinder AG 115B -TC20110
The winner is Michiel of Stellenbosch
In his extensive competition entry, Michiel reminds us what a great philosopher said when it comes to rotting wooden door and window frames:
“The Chinese philosopher and politician Kong Qiu Confucius (who lived between 551 and 478 BC) said: ‘Rotten wood cannot be cured’. So, if such frames are rotten, whether caused by fungus or by wood-destroying insects like beetles, borers, termites or carpenter bees (the insects which you reported on elsewhere in this issue of TO BUILD) replace the wooden frames!
“Such a Tork Craft Angle Grinder with its interchangeable Li-ion batteries will certainly do the trick, saving me time and thus money. The latter because time is money – or so they say. But it will certainly be saving me buckets full of the stuff which I, sad but true, seem to lack nowadays – elbow grease!”
With his further extensive and entertaining account of what use the Tork Craft Angle Grinder can be used for, including some of our advertisers’ products, Michiel wins the prize.
Congratulations, this magnificent cordless tool will be on its way to you shortly, compliments of Vermont Sales.