While drilling wood is fairly easy, drilling metal is tougher. Actually, drilling metal is not especially difficult, as long as you know what you are doing. Here is some basic advice for drilling metal.
Having the right tools is very import. Most modern drills will be powerful enough for metal drilling. While all drill bits will make a hole in wood, you can’t use drill bits meant for wood when drilling metal. HSS drill bits that are coated with titanium nitride work for most metals. Cobalt steel bits, also known as just cobalt bits, may be needed for very hard metals.
Drilling metal requires that you use both hands to keep the drill steady. So unless the metal object is very large and heavy, for example a wall, you need to secure the piece with a vise or something similar. Wearing goggles is highly recommended, hot pieces of metal may hit your face. Gloves are not necessary but do protect your hands from hot slivers of metal.
Mark the center of the hole, using a nail and a hammer. Make sure that you make a small indentation in the metal. It is very easy for the drill bit to slip on the metal. But be careful if you are working with thin metal, if you use too much force you may create a large dent. Put something under the metal to prevent denting a large area.
Hard metals, like steel, require slow speeds, and the larger the hole, the slower the speed. Check your manual for advice. For example, a 4 millimeter hole in steel should be drill at around 1200 RPM. But if you are using an 8 mm drill bit, the speed should be around 800 RPM. For softer metals, for example aluminum, a 4 mm drill bit can be used at about 2600 RPM.
Lubrication is generally needed when drilling metal. The drill bit will get hot and sometimes sparks will fly. Drilling metal takes time, but patience is very important. Also, once you have reached the desired depth, keep the bit spinning while you remove it from the medium.
If you are drilling a large hole, it may be necessary to drill a smaller hole first. This is especially useful if you don’t have a powerful drill. If you require a hole of 10 millimeter, first drilling a pilot hole using a 6 millimeter bit can make the task easier. Sometimes you may find that the quickest way is to use three drill bits, first a small bit, then the medium bit and lastly the drill bit you really need.
It is very important to have sharp drill bits, so if necessary sharpen your bits before you start drilling metal.