Are Black Oxide Drill Bits Good for Metal? [Ultimate Guide]


Drill bits are made with different materials, coatings and structures. These are used for specific material drilling processes. The drill machine and drill bit should be compatible for a successful drilling process. Among the types of drill bits, black oxide drill bits are specially used for metal and wood.

Black oxide drill bits are highly recommended for soft metals such as aluminium, steel, copper, brass, low carbon steel and hardwood such as maple, oak, beech, birch etc. The black oxide coating provides heat resistance and lubricity to the tool and it is a highly corrosion-resistant coating.

Black oxide is a coating that we can apply on the regular drill bit. It can add special characteristics to the drill bit. So let’s see is it good for using the black oxide drill bit for metal.

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What is Black Oxide Drill Bits?

Black oxide drill bits are made with a magnetite layer coated in the regular drill bit (HSS). Black oxide is a conversion coating for ferrous materials, stainless steel etc. The black oxide layer is more important as thermal resistance, heat resistance, and corrosion resistance. When we use black oxide as a drill bit all these are really important. Additionally, it can increase the life of high-speed steel.

High-speed steel (HSS) drill bits are coated with black oxide in order to maintain the above characteristics of the drill bit. When we search more there are three types of black oxides. According to the application method on the surface, it has named.

Hot Black Oxide – Convert the surface into magnetite  (Fe3O4) using sodium hydroxidenitrates, and nitrites at 141 °C (286 °F).

Mid-Temperature Black Oxide – Using low temperature than hot black oxide, surface metal is converted to magnetite (Fe3O4).

Cold Black Oxide – This is an oxide conversion coating. It can be done at 20–30 °C (68–86 °F). This is less abrasion resistance. This is less performance than hot or mid temperature black oxide.

In order to add more properties to the drill bits, it has been subjected to many treatments.

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Where to Use Black Oxide Drill Bits?

The black is the nitride drill bit. It is a chemical method used to improve the tool by placing the finished tool in a mixture of ammonia and water vapour, after 550 to 560 Celsius insulation treatment. Most of the black drills currently on the market are the only black in colour. The quality of a black varies according to the brand.

Some drills are made of very poor carbon steel so it leads to anneal and rust easily. So it is important to do a blackening treatment. 

Black oxide bits are most versatile when it comes to drilling materials. Bits made with black oxide coating are suitable for,

  • For steel
  • copper
  • wood,
  • brass
  • nylon,
  • PVC
  • maple
  • hardwood
  • MDF
  • Polycarbonate
  • ABS
  • Nylone

Black oxide bits have longer 50% durability than the standard HSS bits and if offers speed compared.

Is Black Oxide Drill Bits Stronger Than Titanium?

Black oxide, titanium and cobalt drill bits are the best variant among the drill bits. So you must be pretty confused to choose one.

Out other three cobalt drill bits are harder and also in first place for durability.

Titanium drill bits are only coated with a thin layer of titanium nitride which erodes quickly.

When talking about black oxide, So it is not as hard as titanium. Being affordable and pocket-friendly, black oxide is the right to toys it’s for a handy amateur person as it can use as general-purpose bits. Being hard and tough, cobalt drill bits are used for industrial purposes. If you engage in moderate drilling purposes, a titanium drill will cater for your needs.

Which Drill Bit is Good for Metal?

Usually, drill bits that are for metal can be distinguished by their black colour and sometimes gold in colour. The gold ones are usually coated for extra durability. They are usually made from tungsten, carbide, cobalt or titanium. Checking the drill point is also another way to identify a metal drill from a conventional bit drill.

If you have a wide-angled point it is the metal drill bit you are searching for. Metal bits are also known as high-speed steel (HSS) or twist bits. There is another metal drill bit known as the core drill bit. It has two major works in drilling. One is that can enlarge a hole that already exists and as the other work, it can make an annual cross-section while cutting a hole.

The indexable drill bits are also another kind of metal drill bit and they are very expensive in price. The indexable drill bits have two inserts. You have to use one insert for the outer radius of a hole and the other one is for the inside radius.

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Drilling into a hard surface requires the use of specialized drill bits. Since the metal is harder than other surfaces regular drill bits cannot go through metal.

So you need hard drill bits. HSS, black oxide, cobalt steel and titanium can use to drill metal surfaces. If you want to drill small holes in the metal surface black oxide is enough as it is cheap but if you work engage much energy on metal it’s better to go with a titanium drill or a cobalt drill.

Titanium drill bits are high-speed steel drills with (HSS) as there’s a titanium oxide coating. They are harder and corrosion resistant than black oxide drills. They last much more than regular HSS drill bits and they are good for cutting through any metal including metal sheetings.

All the titanium drill bits are harder than cobalt. They can’t be sharpened because they are coated. Cobalt drill bits are made out of cobalt steel and can be sharpened. If they dissipate heat quickly and high resistance to abrasions they are ideal for drilling through stainless steel, cast-iron, metal and titanium other than black oxide drills and titanium drills. 

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Tom Mackenzy

I am Tom, I am really interested in DIY projects. I have my own workshop and I spend my free time with so many projects. So I would like to share my experience with you regarding power tools, woodworking, metalworking, etc.

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