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How to sharpen a drill bit? Review of the most effective drill bit refurbishment methods

A well-sharpened drill bit is the foundation of precise work. Over time, however, it becomes blunt or deformed. Instead of replacing it with a new one, you can use practical methods for sharpening drill bits. Find out which tools to use and how to do it properly. 

Restore or discard? Why is it worth sharpening drill bits?

Buying a basic drill bit costs a few zlotys. The hardest metal drill bits, however, can cost several dozen or even more than 100 PLN. It might seem that when such tools become blunt the best solution is to replace them. Indeed, with significant wear that may be the optimal choice. However, in many cases it is worth refurbishing high-quality specialist drill bits. For this you can use a professional drill-sharpening jig or other tools, e.g. a grinder. When looking for the best devices for sharpening drill bits remember that there are no universal drill bits. Each one is slightly different, so it requires a different sharpening method. We distinguish flat, spiral and twist (helical) drill bits. There is also a division according to the material they are intended for:
  • for wood
  • for metal with a steel cutting edge 
  • for sheet metal 
  • for concrete, with a carbide tip (so-called carbide/widia drill bits) 
  • multipurpose for metal or concrete with a carbide tip 
  • for plastics
As you can see, drill bits for different applications are made from different materials. This is one of the factors that affects the choice of sharpening method.

How to sharpen drill bits on a grinder?

If you don’t want to invest in a drill-sharpening jig, you can use a regular grinder. This tool is suitable primarily for most larger-diameter drill bits such as e.g. wood drill bits. Unfortunately, a grinder is generally not suitable for sharpening specialist bits – you can easily damage your drill bit that way. How to sharpen a drill bit on a grinder? Choose the appropriate abrasives. It’s best to use aluminium oxide grinding wheels. Hold the drill against the grinding wheel and slowly rotate it in the direction of drilling. Remember to frequently pause the sharpening process – otherwise it may overheat and become damaged. A popular method to increase strength, hardness, wear resistance, but also to raise yield and elasticity, is the so-called hardening of the drill bit. It involves rapidly cooling the material after it has been heated to a high temperature during sharpening. This procedure does contribute to giving the steel the expected properties, but it requires caution. To do it correctly, the duration of the water quench must be chosen appropriately. This requires, among other things, knowledge of the chemical composition of the material being hardened. Improper hardening can lead to deformations or even cracks in the drill bit. 

Grinder-sharpener, i.e. the so-called drill-sharpening machine

Somewhere between a drill-sharpening jig and a grinder used for this purpose is the grinder-sharpener. Importantly, this type of drill-sharpening machine is also suitable for small components – specialist bits. Grinder-sharpeners resemble bench grinders in appearance. However, they are equipped with an additional drill-sharpening holder. They allow smooth and efficient adjustment of rotational speed, which greatly facilitates precise work on bits with different parameters. A drill guide and a special vibration-damping construction provide greater accuracy. This type of device allows you to adjust the sharpening angle of the drill to your needs. Additionally, it is equipped with a small coolant reservoir.

Drill-sharpening jig

If you often need to sharpen drill bits, the most cost-effective solution is to purchase a specialist drill-sharpening jig. It takes the form of a holder mounted, for example, to a grinder, with a built-in support that ensures stability. Simply place the drill bit in the holder, bring it to the correct angle to the grinding stone, set the sharpening depth for metal, glass, etc. according to the enclosed instructions, and finally grind it on each side. This specialist drill-sharpening attachment is essential if you plan to refurbish not only metal drill bits but also, for example, carbide (widia) bits. Sharpening drill bits for concrete and glass must be very precise – it requires maintaining the correct angle and grinding depth. A drill-sharpening jig helps maintain that accuracy, and at the same time is comfortable and easy to use. Such a device is also suitable for small-sized tools. 

When should you entrust drill sharpening to a professional?

Even if you are an expert in your field, in some cases you should entrust work related to drill sharpening to professional workshops specialized in this. This is important, for example, when sharpening step drills. Their specific, conical design significantly complicates DIY sharpening, e.g. with a grinder. Attempting to refurbish such bits, as well as some small specialist bits, on your own may result in damaging them. 
30-day returns

30-day returns

Extended warranty up to 4 years

Extended warranty up to 4 years

Free shipping from 199 zł

Free shipping from 199 zł