How To Drill Into Granite Rock

According to the MOHS hardness scale, granite is one of the hardest materials in the world! It’s no wonder, then, that it is used for so many applications; after all, you won’t find much else with this amount of durability.

But, while it is robust, this can make granite incredibly difficult to work with, especially when it comes to drilling into it.

Your normal drill bits probably won’t have the strength and resistance needed to tackle this tough material, so what can you do? Let’s take a look at how to drill into granite rock.

The best option for drilling granite rock is to use a carbide-tipped masonry bit. It is possible to use a diamond bit but these are typically reserved for drilling granite countertops and the like.

What Is Granite?

Granite is a type of igneous rock that has large grains which is one of the things that makes it so appealing; it has a very unique appearance. This rock is formed below the surface of the earth as a result of magma crystallisation.

As it happens, granite is not a material of its own but is rather a combination of feldspar and quartz. Although there are trace amounts of some other minerals such as mica.

Depending on the level of other minerals, granite may take on a variety of colours including white, pink, grey and even red.

Granite can be problematic in some areas as it is so common all over the world. Many people find that their gardens are ridden with granite and this can make landscaping and other work much more challenging.

In the UK, the majority of granite is found in the south. There were a lot of granite quarries in Devon and Cornwall where there are as many as five huge granite masses.

What’s The Best Type Of Drill For Drilling Into Granite Rock?

One of the most important things to think about when considering how to drill a hole into granite rock is the type of drill you’ll be using.

The problem is that granite is quite brittle, despite being incredibly hard. Now, if you’re drilling through rocks that you simply want to get rid of then it won’t matter much if they crack or split.

In fact, that’ll more than likely work in your favour. However, if you were drilling through a granite countertop, for example, you would need to be very careful.

In this case, you’d want to use a normal drill as the vibrations from a hammer drill would cause too much damage. The key to success lies in choosing the right drill bit and we’ll look at that in a little more detail in the next section.

However, if you’re drilling into a thick slab of granite then a hammer drill or a rotary hammer drill are the obvious choices. This is because of the superior power but what’s more important is that this power is consistent so that you can steadily and evenly drill through the rock.

What’s The Best Drill Bit For Drilling Into Granite Rock?

If you want to successfully drill through granite rock then you’ll also need to think about the type of drill bit you’ll be using. This is almost as, if not more important than choosing the correct drill so pay special attention to this.

Generally speaking, you’d need to select either a tungsten carbide bit or a diamond bit but again, they’re both suited to different applications involving granite.

First and foremost, you’ll need to consider that diamond drill bits are quite a bit more expensive than their carbide-tipped counterparts. But, if you want something that’s going to last a long time, they’re an excellent option. When they’re well maintained, you can expect to get hundreds of uses out of a diamond bit.

That said, these are usually better for drilling through thinner pieces of granite such as a worktop. If you’re drilling through raw granite rock then you’d be better to select a tungsten carbide tipped bit.

While they aren’t as long-lasting, they are efficient and what’s more, they’re a lot more affordable. In fact, you could go through several of these bits and still not fork out as much as you would for a single diamond-tipped bit.

Popular Tungsten Carbide Bits

Popular Diamond Tipped Drill Bits

The Key To Successfully Drilling Through Granite

While having the right tools and equipment to drill through granite is a must, that’s not the only thing you’ll need to consider. You see, one of the biggest problems that people face when drilling through granite is that the drill bit overheats.

Speak to an expert and they’ll tell you that keeping it cool is one of the most essential parts of this process. One of the best ways to do this is to regularly apply cold water to the drill bit. Now, you could keep stopping to do this but there is an alternative method that saves you the hassle.

You’ll need to use an aquarium pump and a bucket of water. Connect the pump to a flood line that is pointed at the drill bit. This way, you can have a consistent stream of cold water on it so there’s no chance of it heating up.

Of course, you’ll need to be careful not to get water into any of the electrical components of your drill otherwise it will become damaged.

Surprisingly, it isn’t the power or the torque that is mainly responsible for successful granite rock drilling. It’s all down to keeping it cool!

Does It Take Long To Drill Through Granite?

Since granite is such a tough material, one could be forgiven for thinking that it’ll take an age and a day to drill through. The good news is that provided you use the right equipment and keep the drill bit cool, you will be able to drill around ¾ inch in about sixty seconds.

Conclusion

Granite is a super hard rock that is found on every continent in the world. However, there are some areas where it is more prevalent and in the UK, this is in the southwest.

Whether you’re trying to drill through granite rock as part of some outdoor work or want to put a hole in a piece of indoor granite, you’ll need to have the right tools.

Using a regular drill bit will not be enough so you’ll need to make sure you choose a carbide tipped or diamond bit.

Moreover, it’s essential to make sure that you choose the right type of drill according to what type of granite you’re drilling. Not doing this could damage the material.