What Size Countersink bit do I need

What Size Countersink bit do I need

What is a countersink? What size countersink bit do I need? Today you will get all the answers. A countersink is known as a conical hole into an object. It is mostly used to insert the head of a screw or bolt.

It can also be used to separate an unwanted piece of material. Also, you can see the improvement in the finished product as well. Do not get confused with counterboring, both are different. Sharp edges can be easily removed by countersinking.

Once you have placed the screw in the countersink, you can either leave it to reveal or hide it using wood putty.

When you want to countersink a screw, you need to make sure that you are using a flat head screw so you can simply place it. It is important to mark the place you are about to drill with a pen or pencil.

The point will help you not to slip when you are drilling. Some people also use lubricants to flush the screw but it’s all up to you. Safety glasses are important to keep your eyes safe.

You need to look into other details as well. When drilling, it is important to be very careful not to go over. If the countersink is too large, the hole will be visible around the head of the screw.

How bad will it look? All the hard work will be wasted. Likewise, if the countersink is too small, the screw head will be partly visible on the surface, which will obviously don’t look good.

What is a countersink bit?

What is a countersink bit?

Any portable or press drill is attached with a tool that is called a countersink bit. It makes a conical hole into the material to allow the screw kept hidden.

The form of the hole is of the same shape as the screw. They are depth adjustable and their bits are removable.

It is important to measure the diameter of the bolt and countersink bit, both should be equal. If you’re drilling into softwood and don’t have the same diameter as the screw, you can make a smaller countersink.

The hole should be neat and do not have rough edges. There are many different sizes of countersink bit but what size countersink bit do I need is the right question.

What are the types of Countersink Bit?

What are the types of Countersink Bit?

Flute-less countersinks are used for drilling. Although, if you want to make more space than you can use single or multiple flute countersinks.

Fluted countersinks come in different sizes. They should be sharped to cut faster. Cross hole countersinks result in very smooth finishing. It does not have any flutes.

They are a bit costlier than fluted countersinks. No doubt, fluted countersinks does have cutting edges however, cross-hole countersinks have a tip with an angled hole to cut the edges.

There are countersinks which have different angles on their heads. 82 and 90 are the frequently used angles. There are some basic types of countersink bits that are mostly used are as follows.

• Tapered bit

The most common type of countersink that is used is the tapered countersink. It has a V-shaped tip. The screw head’s bottom should also be V-shaped. Less effort is applied to use this bit. Most people recommend using this bit rather than a straight bit. It is a little difficult to handle it when you have to control the hole depth.

• Flat bit

It is an old and light type of drill bit. It is of a cylindrical shape. The tip of the bit is flat. Also, the bottom of the screw head is flat. Hexagonal or cylindrical screws can be used for this bit to flush with the surface.

It has two main cutting edges and a centre point. They are quite cheap but does not give a fine look.

• Fixed bit

This countersink bit is not a new bit. It is fixed and hence cannot be moved or replaced.

• Collard bit

This type of bit is very useful because it can be matched with the screw length by moving it up and down. When it is worn, it can be replaceable.

What size countersink bit do I need?

What size countersink bit do I need

What size countersink bit do I need? Well, it depends on the work, which screws you are using, and other details.

There is a large variety of sizes and styles of countersink bits available in the market. Countersink bits are available in various measurements like 40 mm, 35 mm, 20 mm, and 16.5 mm.

For British Standard, almost 230 sizes ranging from 0.2 mm to 25 mm. Measure the screw head with the countersink to get a perfect hole. A simple method is to get a countersink one size larger than the screw size of the hole.


Now, you all got to know that countersink bit is a tool to get a cone-shaped hole in any material. The hole should be enough to place the screw firmly otherwise it will be partially visible.

There are various types of countersink bits coming in different sizes, so what size countersink bit do I need? It depends on different projects.

When you are purchasing them, you must keep in mind the material you would be working with and how deep should be the countersink. Hence, select the bit according to the work for a neat and finish the look.

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