Can I Sharpen a Cobalt Drill Bit?

Cobalt drill bits are one of the best drill bits you can use for custom steel operations and many other challenging materials. 5% or 8% cobalt percentage altogether with hot-work steel makes cobalt drill bits incredibly heat resistant and strong, increasing their longevity. In order to make drilling perfect and convenient, it is necessary to have edgy drill bits. Even though cobalt drill bits are highly resistant to heat and durable, the cutting edges get blunt and require sharpening after using them for a while. 

Can you sharpen a cobalt drill bit?

You can sharpen a cobalt drill bit when it is blunt and dull. When you see smaller chipping and lower feeding rate with high heat generation, it is time to sharpen the cobalt drill bit. You can easily sharpen a cobalt drill bit when it is not coated by any material. If you sharpen a coated cobalt drill bit, its coating will remove, and its characteristics will reduce.

Primarily, cobalt drill bits do not have a coating, and sharpening them will be a piece of cake when you have the right tools. Some cobalt drill bits come with Tin, TiCN, and TiAlN coatings, making sharpening problematic. Let’s find out the sharpening process and other crucial facts you must be aware of regarding this area.

Many tend to go for new drill bits and stop using old ones when the edges get dull, which is an absolute waste of money and tools. Bench grinders are ideal for sharpening cobalt drill bits. You can sharpen them on your own, and it is even easier to sharpen cobalt bits using standard cutting fluid. Consequently, you can regain the edginess of the drill bit and save money in the long run.

When Should I Sharpen A Cobalt Drill Bit?

Like any other drill bit, cobalt drill bits gradually wear off each time you use them, and it is inevitable no matter how well you use them. Following are a few noticeable signs you can identify when it is high time to sharpen your cobalt drill bits.  

  • Drill bits that require sharpening do not operate efficiently. The drilling process will become slow.
  • When your drill bits do not make clean, perfect holes anymore, understand that they are dull and require sharpening.
  • When you notice that you have to apply a lot of pressure and force to get the work done than before.

Please ensure that you always sharpen your drill bits when they get dull. If you keep drilling with a blunt drill bit, it will harm the drill bit and the workpiece.

Cobalt Drill Bit Sharpening Angle And Sharpening Tools

Drill Bit Sharpening Angle

The sharpening angle of the cobalt drill bit depends on the drilling material; You can drill wood, metal, plastic, PVC, and many more materials using a cobalt drill bit. For the hard material, the drill bit angle should be 135°, and for the soft material, it should be 118°.

Drill Bits Sharpening Tool

You can use a hand grinder, file, bench grinder or oil stone as a sharpening tool for the cobalt drill bit. When you sharpen manually, you must have a good user experience because cutting edges should be sharpened well and symmetrically.

If manual sharpening is difficult, you can use a drill bit sharpening gadget. Drill Doctor is one of the drill bit sharpeners and it is available for 3/32″ to 1/2″ twist drill bits. But it can’t use for the left-hand drill bits.

Why Does A Cobalt Drill Bit Break While Drilling?

One disadvantage of cobalt drill bits is unlike HSS drill bits, they are brittle and break when they are not properly maintained. Blunt drill bits do not deliver maximum efficiency while drilling and cause various problems, such as bit breakage.

Cobalt drill bits are vastly used on hard materials rather than soft ones, which can take a lot of time to drill through compared to soft materials. Therefore, When you continuously drill into a hard material using a dull drill bit, they are prone to damage, particularly the center of the flute. Moreover, cobalt drill bits can break if they fall on the ground as they are too brittle.

How To Sharpen A Cobalt Drill Bit?

Using a bench grinder cobalt drill bits can be sharpened
Bench Grinder can be used for cobalt drill bit sharpening

When you use a cobalt drill bit on metal you need to sharpen it frequently. Actually, are cobalt drill bits are good for metal? here is what you should know about it.

The following chart showcases the steps of sharpening cobalt drill bits.

  • Step 01 – Wear a pair of safety glasses to protect your eyes. Do not wear gloves.
  • Step 02 – Turn on the bench grinder and set a low speed.
  • Step 03 – Using your fingers, hold the drill bit from the smooth end at a 60-degree angle.
  • Step 04 – Fasten your hold on the drill bit and bring it towards the grinder. 
  • Step 05 – Let the bit gently contact the grinder with the sloped side of the conical top and start sharpening.
  • Step 06 – Take back the bit from the grinding wheel once you finish with one side. 
  • Step 07 – Repeat this process by sharpening all the sides of the conical top.

Finally, check whether the edges are well-sharpened. You can touch the edges of the drill bit mildly to ensure that it is adequately sharpened. 

Can You Sharpen A Coated Cobalt Drill Bit?

The coating improves the longevity of the drill bit, controlling friction which produces heat while drilling. Yet, sharpening a coated cobalt drill bit can be inarguably disadvantageous, as it damages the coating.

Many tend to replace blunt drill bits with new ones, assuming there is no use in sharpening if it damages the coating. But wait! When it comes to cobalt drill bits, you do not have to worry about losing the coating because cobalt naturally has the ability to withstand heat and is hard enough to drill through rigid materials. So, unlike other drill bits, cobalt drill bits perform well for a considerable time, showcasing high performances without a coating.

When Should You Replace The Cobalt Drill Bit?

Usually, a cobalt drill bit can drill about 1,000 to 2,000 holes in the most challenging materials without a problem. Yet, if a particular drill bit does not make clean, perfect holes anymore, understand that they are dull and require sharpening. But you can not sharpen and reuse drill bits forever. They will either break or wears off eventually, and this is when you should replace your drill bit with a new one.

When the damage is apparent, you will indeed have to replace your cobalt drill with a new drill bit. For instance, you should refrain from using a bent drill bit even though you re-sharpened it. Do not try to use a drill bit once you notice minor breakages. Do not waste your time sharpening it, either! 

Tom Mackency

Tom Mackency

Hi, I am Tom Mackency. It has been 10 years that I have been working as a professional woodworker since 2013. I am really enjoying my carrier by creating many kinds of projects in my workshop. But mostly I like for home improvement projects. Home improvement and DIY projects are the most interesting things for me. More than that, the coolest things are power tools. Those are very precious and efficient than a decade ago. So I try to introduce so many things about power tools, woodworking, DIY projects, home improvement and many more interesting topics here.