Black oxide drill bits are highly recommended for soft metals such as aluminum, 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 it is good to use the black oxide drill bit for metal.
What is a Black Oxide Drill Bit?
Black Oxide drill bit is a magnetite (Fe3O4) coated drill bit. Black oxide can be coated on the HSS and Cobalt drill bits in order to improve performance and reduce the friction between the material and the drill bit. It can transfer the heating quickly. Black oxide coatings are mainly 3 types those are,
- Hot Black Oxide – Convert the surface into magnetite (Fe3O4) using sodium hydroxide, nitrates, and nitrites at 141 °C (286 °F).
- Mid-Temperature Black Oxide – Using low temperatures 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.
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 vapor after 550 to 560 Celsius insulation treatment. Most of the black drills currently on the market are the only black in color. The quality of black varies according to the brand.
What Metals Can be Drilled Using Black Oxide Drill Bits?
Using Black Oxide drill bits you can drill below 30 metals.
- Stainless Steel
- Mild Steel
- Cast Iron
- High Alloy Steel
- Tool Steel
What Materials Can be Drilled Using Black Oxide Drill Bits?
Black oxide drill bits can be used for drilling soft metals such as aluminum, steel, copper, and brass with lower carbon steel. Black oxide is a thin coated layer around the HSS drill bits. Hence it can be used to drill metals with lower friction and lower thermal resistance, and the layer can increase the durability of the drill bit.
Black oxide drill bits can be used to drill the below materials,
- Soft metals
Black oxide bits have longer 50% durability than the standard HSS bits.
What Drill Bits are Good for Metals?
The most used drill bits are TiN, TiAlN, TiCN, HSS, Black Oxide, Cobalt, and Titanium. These drill bits can be used on specific metal types. Below are the metal types and suitable drill bits for each metal types.
|Metal types||Suitable Drill Bits|
|Aluminum||HSS, TiN, TiCN|
|Stainless Steel||Cobalt, Titanium, TiAlN|
|Cast Iron||HSS, Black Oxide|
|Bronze||HSS, Black Oxide|
|Nickel||Titanium, TiN, HSS|
|Carbon Steel||TiAlN, HSS|
|Alloy Steel||Cobalt, TiCN|
|Mild Steel||Black Oxide, HSS|
|High Carbon Steel||Cobalt, Titanium|
|Tool Steel||TiAlN, TiCN|
|Chrome||Cobalt, Black Oxide|