Drilling in metal requires preparation of proper tools and a bit of experience. Processing of this material can be difficult, especially for less experienced DIY enthusiasts. So, how to effectively drill holes in metal and what drill bits will work best? In today's article, we will describe this process in detail and present appropriate technological solutions.
METAL DRILL BITS – TYPES, USE
- Universal drills – a very popular type of drill, mainly due to its versatility and low price. They can be used for drilling not only in metal, but also in plastics and wood. They are perfect for drilling in copper, aluminium or other soft metals.
- Widia drills – made of cemented carbide. They are successfully used for processing stainless steel and steel with higher hardness (including railway and alloy steel). They will also work well when drilling in cast iron and titanium alloy elements.
- Cobalt drills – also have some universality. They are perfect for processing both soft and hard materials. They are characterized by several times higher strength than traditional steel drill bits. This type of drill bit has a special cobalt coating, which makes it more resistant to abrasion and blunting. The main material used in their production is chrome-vanadium steel. Cobalt drills are most often marked with the symbol HSSCo or HSS-Co.
- HSS high speed steel drills – another popular type of drills. They are perfect for drilling in metal, stainless steel and hard steel. They will also work well when processing other materials, such as wood or plastic elements. HSS drill bits are characterized by high drilling precision.
- Titanium (TiN) drills – quite specific, but also a popular group of drills among more experienced DIY enthusiasts. These drill bits are coated with a special titanium nitride coating. They are characterized by considerable resistance to abrasion and are used for drilling ,e.g. in hard steel, stainless steel and hard metal. Overall, titanium drills are tougher than the previously discussed cobalt drills. Finally, an important note! When processing aluminium alloys with this drill, adequate cooling must be used.
- Diamond drill bits – contrary to general opinion, these drill bits are not entirely made of synthetic diamond. It is only used to strengthen the drill tip. Thanks to this, the greatest resistance to blunting and abrasion is achieved. Diamond drill bits are used for processing hard metals and iron.
DRILLING IN SOFT METAL – WHERE TO START?
You will need a drill and a metal drill bit to make a hole in soft metal. While the type of drill practically should not make difference, not every drill bit is suitable for drilling in this material. Well, you should get a special metal drill – even the cheapest. Carbon steel or high-speed steel is most often used for their production. In the case of soft metals, polished or rolled drills are perfect.
HOW TO DRILL IN SOFT METAL?
We already know what equipment should be used for drilling in copper, brass, aluminium or other soft metal. The second question is how to drill. Surprisingly, it is not so simple. The drill bit may slip on the surface at first and jam when drilling. So, how can you make your job easier and avoid drilling problems?
Just stick to a few important tips:
- Before drilling, take exact measurements of the diameter of the drill bit and mark the drilling location.
- Use the maximum rotation speed of the drill to make the hole in the shortest possible time.
- If the metal surface is slippery, you can punch the drilling area with a centre punch or use a smaller drill bit. It will minimize the problem of the drill bit slipping.
- Do not use too much pressure when drilling.
DRILLING IN HARD METAL – IMPORTANT TIPS
In order to effectively drill in harder materials, the most important thing is to choose the right type of a drill. In this case, it is recommended to use more expensive cobalt, titanium or diamond units. When drilling in hard metal, it is very important to put a slightly higher pressure on the drill than for soft metal alloys. Too little pressure will cause the sliding of the drill bit over the material and it will generate heat excess, which can burn the walls of the hole or even permanently damage the drill.
WHAT ROTATIONAL SPEED FOR DRILLING IN METAL?
As a general rule, the harder the material is, the slower the drilling speed should be. In fact, in the case of metal processing, this rule can be considered correct, but from a practical point of view, the correct setting of the drilling speed will be a bit difficult.
It depends not only on the hardness of the element, but also on the diameter of the drill – the smaller the diameter, the higher the cutting speed. Due to the fact that maintaining and giving a specific rotational speed in handheld drills is almost impossible, the success of drilling will be largely determined by skilled hands and operator experience.
OVERHEATED DRILL BIT – HOW TO DISSIPATE HEAT WHILE DRILLING?
The high temperature generated when drilling into metal should be effectively dissipated. Otherwise, it can drastically reduce the durability of the drill or even lead to its destruction. During drilling, heat is dissipated by the escaping shavings and is absorbed by the drill bit and the material being processed.
While in the case of thin metal layers, a short-term increase in temperature in the drilling area should not be a problem, in the case of hard alloys, it can be problematic. Then it is a good idea to use the appropriate coolant. However, regardless of the type of metal being processed, plain water coolant, which can cause corrosion, should be avoided. For this purpose, special oils and lubricants are used, which not only effectively dissipate heat, but also reduce friction.
