A step drill bit is used on metal at a slower speed. The right drill bit makes all the difference between good and bad work. Only a small amount of pressure is needed with an appropriate and sharp bit.
The range of drill bits results from the vast range of materials that need to be drilled. The bits cost more or less depending on the material used, its coating, and its purpose.
Types of Drills
Wood drills are cheap, as they are made of steel. High speed and titanium coated bits are harder and more durable, while cobalt or carbide tipped drills are even more so as well as being the most expensive.
How a Step Drill Works
The step drill bit drills holes by rotating in a clockwise direction, through metal sheets of up to ¼ inch thick. Each step in the drill enlarges the original hole. The smallest bits are self-starting in that they need no pilot drill to start off the hole.
Larger Step Drill Bits
Larger bits require a pre-drilled hole to the diameter of the smallest step on the bit. A center punch is used to make a central dent where the hole will be. This helps the drill not to drift when you first start drilling. Cutting fluid is needed on the bit to prevent overheating. The smaller step drill is run right through the metal. It is then replaced with the larger drill, which is drilled through to the size of the hole needed.
Using the correct drill bit is not only important for getting the job done, but for getting it done safely as well.