Best Drill Bits for Metal

In this article I will review what we believe to be the best drill bits for getting through metal.

I am sure that you are aware, there are many different types of metal that include iron, steel, brass, chrome, copper, lead, tin, titanium, zinc, aluminium etc. In many cases though, the most popular type of metal that needs to be drilled though, is some variety of steel.

Most of the metals are classed as hard materials, and as such they require special drill bits to be able to get through them easily. There are plenty of choices available.

In this article I will take you through what I believe to be the best drill bits, and drill bit sets for getting through the different types of metals.

Understanding Drill Bit Speeds for Metal

There are a number of considerations to examine when it comes to drilling at the right speed through metal. The one thing you should remember that drilling too fast, will cause your drill bits to burn out very quickly.

That is one of the main reasons why it is vital to have a variable speed setting on the drill that you are using. Most drills will come with a manual and in there you should find the recommended speeds for the different materials including the metals.

With a softer metal like aluminium you can go faster, but in my opinion slower is always best to stop ruining your drill bits.

Hole Size

 What should really guide your speed is the actual size of the hole that you are drilling. The bigger the diameter of the hole, the slower that you need to go, is always the golden rule.

At the bottom of the page I have included a Drill Bit RPM Guide for Metals

Best Drill Bit Sets for Metal

There are some very good general purpose drill bit sets, that are ideal for drilling a variety of different sized holes in most metals. The beauty of these types of sets, is that you have a good wide range of different sized bits.

You will always get the most commonly used sizes, and also some at the lower size, and some at the higher size values. The beauty of the sets is that you will almost always get much better value for money, than if you were buying them as individual bits.

The downside is that you usually end up with some bits that you will never, or hardly ever use. It is question of deciding if these are the better value choice for you.

For most people though a drill bet set for metal is a very good idea. I have shown below a few of my favorite sets, that sell really well and get very high ratings from those who have bought and used them.

Best Drill Bit Sets for Steel

Likewise you can also buy drill bit sets that are designed to be able to drill through many of the steels that are available on the market. These include normal steel and stainless steel.

This is the metal that most people have to drill through. Normal bits that I have shown below will be able to drill through steel very well.

Hardened steel is a different metal, and I have included a section just below just on that material. If you need to drill through that, then check out the section below.

Best Drill Bits for Hardened Steel

Hardened steel is a particularly tough metal to get through. These require a special type of drill bit. I have done a more detailed article on the types of drill bit required to get through this very tough metal.

When steel is hardened it is heated to very high temperatures. It can however only be hardened and tempered if the steel contains high quantities of carbon.

When steel is heated it becomes quite brittle, and the tempering process then reduces the hardness slightly, to remove this brittle nature. It is one of the more tough metals to drill through.

Best Drill Bit Sets for Brass

Brass is an interesting metal, and one that I really do enjoy working with. Most of the general metal drilling bits will go through brass, however there are drill bits that are better for drilling through brass.

The set to the right seems to be a very popular choice with buyers. This is a set of titanium coated HSS step drill bits, a good choice for making different sized holes.

Drilling Through Metal Problems and Solutions

Below I have listed some very common problems that people discover when they drill through metal. I have provided what the problem is likely to be and how to resolve that.

Problem - the drill bit is making a high pitched squealing noise

Solution - Most likely the drill bit is running too fast. You can either slow down the speed, or if you don't have a variable speed, drill in short bursts, leaving time in between each drilling session

Problem - The drill bit becomes very hot

Solution - This can be caused by one of two things. Like the problem above the drill bit is going too fast. If that is the case, then the same solution as shown above will help solve that problem.

Secondly the drill bit may require some lubrication. You can buy spray tins of drilling and cutting oil to help resolve this problem. You can also use water to help keep the drill bit cool.

Be careful with water though especially if you are using a power drill plugged into an electricity supply.

Problem - your drill bits get blunt very quickly

Solution - the solution to this is that your drill bits are over heating and you should use lubricant as explained above. Just be aware though that if the drill bits have been over heated a lot, they are practically useless and may need replacing.

Most drill bits can be sharpened, but that takes some skill, and it is always better to buy a drill sharpener machine.

Problem - the drill bit is wobbling

Solution - The bit may not be centred in the chuck, so always check that first. That is always a big problem when using very small bits, such as when you are drilling a pilot hole. Often the drill bit gets caught in just one jaw of the chuck, and it is off center.

The other problem could be that the drill bit has been damaged, and is bent or even slightly warped. If that is the case, then it will need to be replaced.

Problem - the drill bit slips and skids across the metal surface

Solution - No matter what type of metal you are drilling, there should always be a pilot hole drilled first. Usually this is done using a very small drill such as a 3 mm drill bit.

However before that, a center punch should be used to make a dent in the metal, that will accommodate the pilot hole drill bit. Makes sure that you do that, and that it is deep enough to allow the small metal drill bit to grab the metal.

Problem - Drill Bit Jams in the Chuck at the end of the drilling

Solution - this is one of the most common problems when drilling through metal. The honest answer is that this is usually caused by our impatience. It is all too easy when getting near the end of the hole, to force it through.

Too much pressure or weight on the drill bit will cause the drill bit to jam or lock up in the chuck if we try to force it through. Go easy on the pressure and allow the drill bit to cut all the way through the metal.

‚ÄčDrill Bit RPM Guide & Chart for Drilling Speeds

As mentioned earlier in the article, I have included a speed drilling guide for metal.

Please note the drill bit size is shown in inches, and the RPM is shown as the maximum RPM the drill bit should be used when drilling.

Drill Size

Aluminum

Mild Steel

Cast Iron

Stainless Steel

1/32"

36600

13446

12224

8557

3/64"

24448

8964

8149

5705

1/16"

18336

6723

6112

4278

5/64"

14669

5379

4890

3423

3/32"

12224

4482

4075

2852

7/64"

10478

3842

3493

2445

1/8"

9168

3362

3056

2139

9/64"

8149

2988

2716

1902

5/32"

7334

2689

2445

1711

11/64"

6668

2445

2223

1556

3/16"

6112

2241

2037

1426

13/64"

5642

2069

1881

1316

7/32"

5239

1921

1746

1222

15/64"

4890

1793

1630

1141

1/4"

4584

1681

1528

1070

17/64"

4314

1582

1438

1007

9/32"

4075

1494

1358

951

19/64"

3860

1415

1287

901

5/16"

3667

1345

1222

856

21/64"

3493

1281

1164

815

11/32"

3334

1222

1111

778

23/64"

3189

1169

1063

744

3/8"

3056

1121

1019

713

25/64"

2934

1076

978

685

13/32"

2821

1034

940

658

27/64"

2716

996

905

634

7/16"

2619

960

873

611

29/64"

2529

927

843

590

15/32"

2445

896

815

570

31/64"

2366

868

789

552

1/2"

2292

840

764

535

Hopefully I have provided you with enough information to allow you to pick the best drill buts for drilling metal. Thankfully most home owners will have very little need to do this.

For those that do I hope this article has helped you out.

Enda McLarnon
 

Enda McLarnon is now retired and is now enjoying writing about his love of power tools. All types of these tools are now available and they make working on projects and DIY jobs around the home a great deal of fun