A drill is an essential part of a tool kit, along with a hammer and a set of screwdrivers, nails, screws and glue. Drills can be used to make holes but can also be used to turn screws, depending on the bit that you are using. Most drills can spin in a clockwise or counter-clockwise direction, which makes it possible to screw and unscrew and to easily remove and retract the drill from a hole.
A drill has a shank, which is the part of the device to which a drill bit is attached by fixing it to the chuck of the drill (so that the cutting side of the drill bit is facing one way, and the end of the drill bit is attached to the machine).
The twisting rate of a bit depends on the part of the bit that is called the spiral. This spiral is responsible for the amount of chip removal when drilling. Drill bits for metal with a low spiral count are used to make holes in difficult materials such as metal and copper. These materials can cling on to the bit or clog the hole that is being drilled and a special drill bit for metal helps to deal with this problem.
The angle that you will find at the very tip of the bit for metal is different every time, depending on the type of material that you are drilling into. Very tough materials need a stronger pointed angle but soft material needs a sharpened angle on the bit. This tip of the bit enables you to drill a hole in the material and stops the material from ‘ wandering’ at the same time, whilst controlling the shape of the hole that is being drilled.
Of course the length of drill bits for metal is very important. If you want to be able to control the shape and depth of the hole that is being drilled without much effort, it is often better to choose a stub or screw machine length bit. The longer the drill bit is, the more prone it is t bending in the process of drilling. Longer or very long bits for metal are referred to as taper or long bits.
What are drill bits for metal made of?
Drill bit can be made from a range of strong materials. The most inexpensive bits are usually made of soft steel with a low carbon content. These bits often do not hold edges and must be sharpened before drilling. They are best used for drilling in soft wood and are not suitable for drilling in metal at all. High carbon steel bits are much stronger and durable because they have undergone a tempering and hardening process during fabrication. The downside with these bits is the fact that they can become overheated when drilling for a longer period of time and may lose their shape as a result of this. High carbon bits can be used for drilling in metal or wood.
Stainless steel can be drilled into with high speed steel (HSS) metal drill bits. These bits are very tough, maintain their shape and are mostly used for drilling in metals and different types of hard wood. The best drill bits for metal are cobalt steel bits. These bits can even be used to drill in stainless steel, but because of the hardness of the bits, they can be brittle and prone to cracking or breaking when drilling, especially if a lot of pressure and weight are applied to the drill.
Tungsten drill bits for metal can basically take on any type of material when drilling. These bits are often quite expensive but last a lifetime if kept in good condition. There are bits for metal on the market with a tungsten tip, making the bit suitable for multi-purpose drilling.
Choose the right drill bit …
There are specific types of bits for metal, such as center bits. These bits are used to create a starter hole after which a larger bit is used to continue boring. More often than not a center bit for metal is used to make a starter hole for a lathe center bit. A spotting can be used for this same task.
Another type of drill bit for metal is a spade bit. This type of bit is made out of two parts, a tip (insertable) and a holder. The tips used with these metal drill bits are called inserts. Often these bits have some type of cooling agent running rough them and are mostly used for creating so-called stepped holes. If you want to drill in brass or copper materials, which are softer than for example stainless steel, it is important to use a bit for metal without a helical twist. The best thing to use is a fluted bit, as this type of bit does not dig into the soft metal like a regular bit would.
The first thing you need to know is exactly what type of material you are going to use. Based on that knowledge you can start picking the right drill bits for metal. Is it a softer metal? Pick a fluted drill bit. Are you cutting in tough steel? Go with HSS bits. Some times it is even possible to rent a full drilling kit from a store. If you decide to rent a drill, make sure to explain that you will be using metal in your project, or you might end up with the wrong bits!
If you know for sure that you will be working with metal on a regular basis it is a good idea to buy one or two high quality bits to add to your tools. Make sure to keep them dry and clean them with a dry cloth after use. Keep a separate case just for your drill bits and organize them so that you know exactly what bit to use for any type of material that you work with. This way you’ll easily be able to fid the exact piece you are looking for.