How Long Do Drill Bits Last?

Drill bits can become dull over time due to extreme heat from drilling holes on rigid surfaces and due to improper use. Friction and extreme heat can wear down the bit's critical cutting edges, making drilling jobs more difficult and time-consuming.

So how long do drill bit last? Drill bits can wear out much faster than you think.  It will depend on various factors such as sharpness, drill speed, and the type of drill bit used. For example, a cobalt drill bit will last longer than regular high-speed steel (HSS). But, on the other hand, the tungsten carbide drill bit will last longer than the cobalt drill bit.

How long the drill bits last can also depend on the material being drilled. It is also affected by the thickness and type of material drilled. For example:

• You should expect to drill between 150 and 250 holes in concrete with each drill bit.
• High-speed steel (HSS) can drill from 150 to 450 holes in stainless steel, aluminum, structural steel, and low carbon steel. 
• A cobalt drill bit can drill as much as 1,000 to 2,000 holes on stainless steel, alloy steel, aluminum alloys, carbon steel, cast iron, structural steel, brass, and bronze.
• The tungsten carbide drill can drill 1,500 to 10,000 holes in aluminum, aluminum alloys, copper alloys, stainless steel, alloy steel, carbon steel, cast irons, and structural steel. 

But, of course, the harder the material, the fewer drill holes you can make. 

What causes a drill bit to break

Drilling into hard surfaces may cause the drill bit to break and, in some cases, become stuck. A drill usually breaks at the end of the flute due to radial force. On the other hand, high torque will cause the drill to break in the center of the flute.

One of the most common reasons for drill bit breaking is poor drill bit strength and quality. Cheaper drill bits tend to use lower-quality materials and are prone to damage. In addition, they will not resist high torque and radial forces, causing them to break. 

Extremely high temperatures are generated during drilling. If you drill for too long in one place without stopping, it will become too hot and break. You can use coolants and lubricants to keep the drill bit cool and lubricated. You can also pause in between drilling to let the drill bit cool down to minimize the risk of breaking.

When there is a substantial chip load, drill bit breakage can occur.  To reduce breakage, use the appropriate chip load. As specified by toolmakers, Chip Load is the distance the material is carried into the cutter at the tool's centerline.

If you're using a drill, make sure you have the right speed and feed rate so that the drill bit will not break. Check the cutting speed and adjust the speed and feed rate as needed. Because of different drilling conditions, it’s impossible to set strict rules for feeds and speeds. Always adhere to the manufacturer's recommended speed and feed rate.

Why isn't my drill making a hole

The most typical reason a drill will not penetrate is if it rotates in the wrong way. It will be tough to make a hole if your drill is set to turn in the opposite direction. Check the switch and see whether it's set to rotate clockwise for a forward motion. 

Check also if it is set at the proper speed. Depending on the type of materials, a slower or higher speed than recommended will cause it to reduce the drill’s performance which makes it hard for you to make a hole.

If your drill bit cannot drill through the surface and fails to penetrate it, it is likely a dull drill bit. Look for signs of chipping or damage on the surface. The issue should be fixed by replacing the drill bit with a newer one.

When should you replace drill bits

In general, you can continue to use the drill as long as your holes are within the tolerance level, which means the wear is less than half a millimeter. When you observe visible wear or drilling takes longer than usual, then it's time to sharpen, regrind or replace your drill bit. 

Keep an eye out for chipping in the drill bit. It is safe to regrind or sharpen if the chipping is even. However, if the damage to the bits is too apparent, the drill is no longer effective, and you should purchase a new one.

How to Sharpen a Drill Bit

Sharpening your drill bits can help them last longer and keep their edges sharp. Sharpening tools such as a grindstone jig, grinder, and drill sharpener can be used to sharpen them. A drill bit contains two cutting surfaces, one on either side of its center axis, both of which are cut at an angle of around 60 degrees.

Cobalt drill bits have strong heat resistance, making them ideal for frequent usage. However, the cutting edge gets worn out and needs sharpening after a while. You can sharpen the drill bits yourself if you have a bench grinder. Just follow the steps below:

1. Wear gloves and safety glasses and gloves to protect them from flying steel shards.
2. Check your drill bit for severe damage before sharpening it. If there is too much chipping, do not attempt sharpening and disposed of the drill bit immediately.
3. Set the bench grinder to a low rpm and turn it on.
4. Angle the drill about 60 degrees away from the grinder. Make sure the cutting edge is horizontal. 
5. Tilt the drill bit down about 60 degrees. Grind the cutting edge in until the opposite cutting edge is visible. 
6. Check if the entire edge was sharpened correctly.
7. Repeat the steps with the remaining cutting edge. Ensure that both have the same length and angle. 
8. Inspect both cutting edges and make any necessary improvements.

Feel free to take a look at our collection of drills, if you feel your drills are wearing out and need replacing. At Quality Tools UK we only offer the best type of drills on the market, so you can be certain they will sustain a lot of use. If you are still confused as to whether you need to replace your drills, feel free to get in touch with our team who will be on hand to offer advice.