Sharpening drills - this is how it works!

The basic tools in every workshop of a do-it-yourselfer and professional inevitably include a drill and the associated drill bits. They are essential when drilling in different materials such as wood, metal or stone. However, after a certain period of use, a drill reaches a state in which it is too worn to carry out precise work. However, this does not necessarily mean that you have to buy a new drill immediately. Similar to pencils or colored pencils, worn drill bits can also be restored to a sharp condition. Depending on the type of drill, there are different methods to achieve this.

Why is sharpening drills important?

Not only are blunt drill attachments annoying and imprecise in their function, they also pose a number of risks. These range from drills breaking off in the drill hole to potential dangers from flying pieces of metal. Additionally, using worn attachments can cause overheating, which can leave unwanted burn marks on the wood or even damage the drill.

To prevent such problems, it is advisable to regularly check the sharpness of the drilling tools and sharpen them if necessary. Both metal drills and stone and wood drills can be sharpened several times to make them functional and safe again.

How and with which tools different types of drills are sharpened?

There are basically three types of drill bits that can be sharpened:

• Twist or metal drill
• Stone drill
• wood drill

They differ in their material and shape, which is why they are sharpened in different ways. Twist drills can be prepared using either a file, a bench grinder or a special drill sharpener. Masonry drills have rather simple cutting surfaces and can be made sharp again with a file or bench grinder. Wood drills are more complex due to their special drill tip.

Manual sharpening with certain files is recommended for do-it-yourselfers. Although sharpening wood drill bits by hand is more labor-intensive, it typically produces more accurate results.

Tip

Diamond abrasives are required for sharpening HSS drills (high-speed steel or high-speed steel). This is due to the exceptionally hard alloy of these drill bits, which is too hard for traditional key or needle files. Some special drill sharpeners are already designed for this and do not require any additional tools.

What needs to be taken into account when sharpening different types of drills?

When sharpening, the aspects to be considered vary depending on the geometry and material of the respective drill.

Metal drill bits have a tip that tapers at a precise 118° angle. If this angle is made too acute or too shallow during sharpening, it can cause problems when drilling - either the tip gets too hot and melts, or the drill doesn't penetrate deep enough into the material. Therefore, the angle should be maintained as accurately as possible. A drill jig, a small metal tool with precisely punched angles, makes sharpening easier. A special drill sharpener can also make this task easier.

Stone drills are less often sharpened because of their particularly hard tip. Eye protection should always be worn, as metal parts of the drill bit can chip off during sharpening and pose a risk. For accurate sharpening, a sharpener with preset angles is useful to achieve optimal results.

Sharpening wood drill bits is a little more difficult compared to the other two types of drill bits due to the complex center point. Although there are professional grinders with devices for sharpening wood drill bits, the high cost makes them less attractive to amateur DIY enthusiasts. A cheaper alternative is manual sharpening using a vice and file. Although this may take more time, it also allows for accurate grinding of the cutting surfaces and tip.

Sharpening challenges

Aspects such as the shape of the drill tip, the angle and the material influence the sharpening process of a drill. Taking these factors into account can make grinding much easier and produce an excellent result.

When using a bench grinder, it is particularly important not to press the drill too hard. Under no circumstances should the tip glow, as this negatively changes the material properties and makes the drill unusable. You can tell whether the tip has glowed by the bluish discoloration of the tip when it has cooled down.

Final thoughts: Should you grind it yourself, have it grinded or buy a new drill?

If a drill is severely damaged due to intensive use or improper handling, re-sharpening is usually no longer possible. In this case, the only option is to buy a new drill. However, if the drill bits have only become slightly dull, regrinding is definitely worth it as it is both cost-saving and environmentally friendly. DIYers who already have experience with diamond files and other tools and have both skill and time can sharpen their old drill bits by hand.

For those looking for a quick solution to sharpening twist drill bits, a drill bit sharpener is the answer. It also enables less experienced do-it-yourselfers to quickly re-sharpen the cutting tools. To ensure that the drill is sharpened evenly on both sides, turn it once. This way it regains its full sharpness and is ready for renewed use.