In addition to the correct choice of drill in the work activity, it is also very important to choose the drills to be used, because for each type of material there are more suitable drills, promoting better drilling without unnecessarily forcing your drill or damaging your drills early.
In the case of drills, there are a multitude of models, applications, materials, fittings, tips or tools, combined drills, among others. In this article, we will highlight the most usual ones that serve a large percentage of the universe of professionals such as carpenters, carpenters, electricians, mechanics, and civil construction.
- Drills for concrete
Concrete drills are produced in steel in a helical shape that has the function of extracting dust from inside the hole. At the end, intended for drilling, there is a glass tip that has the necessary hardness to cut concrete, masonry, ceramics.
The drills have different sections and lengths and the use depends on the application. The most common ones are used for fixing dowels and anchors on walls, floors or slabs and these are shorter in length and have the most commonly used diameters up to 10mm. There are drills with longer lengths, with 25 to 30 cm, used to go through walls, the most found diameters are between 1/4 ″ and 1 ″.
Concrete drills are used with hammer or impact drills to both speeds up and decrease the user’s effort when drilling. It is advisable at the beginning of the drilling to mark the point to be drilled with a punch and not to use the drill in hammer mode, thus, with the smoothest rotation, there is less risk of the drill going out of the direction of the point to be drilled. When the bit is already inserted in the wall enough to ensure that the tip of the bit will not go out of direction (around 1 cm) change the key to the impact position and continue drilling.
- Drills for wood
Drill three tips.
The most common drills used in the wood are three-pointed drills, made of carbon steel. The central tip is used to position the drill bit in the correct location and guide the hole, the other two tips promote a precise edge cut. They are helical drills with a longitudinal thread along the edge allowing the drill to be aligned in the hole but promoting perfect ventilation and cooling of the drill. The helical design allows the chip to be expelled when drilling. These types of drill bits are usually found in sections up to 10mm.
For larger sections between 1/2 ″ and 1.3 / 8 ″ (35mm), flat drills are used more. They also have three tips with the same functions described for the helical, but the flat blade produces larger chips and because the drill has a larger hole, the rotation of the drill already expels the chip and promotes the cooling of the drill.
Another type of wood drill is the Forstner type, widely used to drill holes for hinge drums, they also have the three tips, but they are not as prominent as flat drills, since these are not used to pass through sheets of wood. wood.
It is not uncommon to see metal drills being used to drill holes in wood. For less dense or soft woods these drills have satisfactory performance, for hard or higher density wood the use of metal drills may lose the cut or overheat in the friction of the drill body with the hole walls, losing the necessary temper for cuts in metal. A slower drilling speed must be respected or drilling in stages by removing the chips from the groove of the high-speed steel drills to allow the drill to cool and thus prevent it from breaking.
- Drills for metal
They are produced in high-speed steel in helical format. They are sharp with the right angle for a perfect cut in metals. For cutting metals, care must be taken with the rotation speeds and the axial (drilling) speed. The lower rotation speed of the drill (between 300 and 900 rpm) allows the drill to cool, normally a fluid is used to enhance the heat exchange. The cooling of the drill must be constant. In case the drill overheats and causes cooling with a volume of cold water, for example, and doing this several times will “unscrew” the drill, reaching the point where it is no longer possible to drill holes. Axial speed is important because if you force the drill too hard against the metal to be drilled, the drill is very sharp, it may sink and fail to produce a thick chip which causes the drill to lock and may break it. Because it is built with a metal alloy that gives it a characteristic hardness, when drilling the hole, any misalignment of the drill in the direction of twisting the drill will break it.
- Drills for mixed-use
A versatile use drill found on the market is a multipurpose or mixed-use drill, which can be used for metal, wood and concrete. For those who do not want to increase volume and weight in the tool, bag is a good option.
Regardless of the drill and the material to be drilled, the use of this tool should only be in the axial direction. Forcing the drill and drills in the lateral direction to open the holes is an incorrect way of working, bringing risks, such as starting to drill and having this projection on the operator’s face. Very important the proper use of PPE such as gloves, glasses, and ear protectors.