Using the right drill is very important but you also need good drill bits. Needless to say, no drill bit is perfect for all jobs. Knowing what drill bit to use can be difficult to find out. Drill bits are available in numerous forms, material and coatings. What kind of drill bits you need depends on what kind of drilling you are going to do.
Just to make sure that your drill bits are performing optimally, remember some rules of thumb.
– Use slow drilling speed when working with hard material
– Use fast drilling speed when working with soft material
– Lift the drill frequently, to clear the flutes of the drill bit and to increase air flow
– Always let drill bits cool naturally, don’t use water to cool them quickly
Drill bits are made of a lot different material but most of them are made of steel. The cheaper drill bits are generally made of low carbon steel. They are softer than drills bits made of high carbon steel. The low carbon steel drill bits are not suitable for drilling in metal instead they are used for drilling in wood. In order to increase their life span they need to be sharpened regularly. The main advantage of low carbon steel drill bits is low price. High carbon steel bits are more expensive but can be used for both metal and wood drilling.
High Speed Steel (HSS) is a type of tool steel that can withstand high temperatures. This means that HSS drill bits can be used for most materials. HSS drill bits are available with various coating material. Thanks to its superior qualities, HSS drill bits have become the choice of the professionals.
Other materials used for drill bits include cobalt steel alloys, which is similar to High Speed Steel. The advantage of cobalt is that it is less susceptible to high temperatures than HSS. The main disadvantage is that it is more brittle than HSS. Tungsten carbide is very hard and is suitable for extremely hard materials. Due to high cost and brittleness, they are often used as drill bit tips. Polycrystalline diamond (PCD) is extremely hard and used for drill bits or drill bit tips in special cases there downtime for replacing or sharpening drill bits is extremely expensive, for example in automotive industries.
Numerous coatings exist for drill bits. The cheapest of the most common coatings is black oxide. It provides heat resistance, lubrication and corrosion resistance. Black oxide coating is used to increase the life span of steel drill bits. Titanium nitride, sometimes together with aluminium or carbon, is an extremely hard ceramic material. It is often used to coat HSS bits to increase their life time.