Drilling steel - That's how it works

Having to drill holes in steel can be a difficult task. Which tool is the right one for you and how to proceed correctly is explained in detail in this article. In addition, what you have to pay special attention to individual types of steel.

Important requirements for drilling

First of all, you should take a close look at where you want to drill the hole:

  • steel grade
  • Thickness of the workpiece that needs to be drilled
  • Diameter of the hole

These facts are important for a start. Then you should start to choose the right tool.

Suitable drills

For steel are best suited carbide drills. If you particularly want to pierce stainless steel, hardened steels or thick, stainless steels, you should definitely resort to high-quality drills. Such drills are either alloyed with cobalt or coated with titanium. Diamond coatings are also available. For such purposes only suitable hard drills are suitable. They are often referred to as HSS drills (high performance, high speed steel). But always pay attention to the appropriate coating.

However, if you want to pierce steel sheet, there are special metal drills that have a center point like a wood drill. This helps center the drill bit before drilling. However, you should not use these drills for other steel workpieces.

cutting oil

To cool the drill, which heats up when drilling, you need to cool it. There are appropriate cooling agents (cooling oil). Coolants simultaneously lubricate the drill and make drilling easier. Water-miscible (or water-mixed) cooling lubricants dissipate the heat even better from the drill. As a result, a more precise machining is possible at the end, and there is less burr formation.

centrepunch

In order to prevent the drill from slipping, you should definitely graze the drill site beforehand. Use a hammer and a metal grit for this. When drilling sheet metal, you can avoid graining by using special drills with a center point.

Properly drill

Under no circumstances use the hammer drill function!

  • The drilling speed should definitely be reduced, sufficient cooling of the drill is a matter of course
  • In the meantime, ventilate the drill again and again, which also extends its service life
  • Pre-drill holes larger than 6 mm in diameter with a thinner drill.

As a rule of thumb for the correct drilling speed, use the 6,000 / drill diameter. The harder the steel, the more you should reduce the speed.

Tips & Tricks

Also check the grade of steel before drilling to see if it is prone to strain hardening. In this case, you will need to drill very slowly, as too high drilling speeds harden the steel by itself and make it much more difficult to drill. Some types of steel have this property.

Video Board: Best Drill Bits For Metal, Stainless Steel and Hardened Steel