Drill Chuck Sizes - What Chuck Key Do You Need for Better Work (2023)

To know about the drill chuck sizes is very important to every DIY lovers. Have you ever lost the chuck key of the drill machine? If so, you know that finding something more unpleasant is very difficult.

The drill chuck key is one of the most important things in the drilling process, and if it is not there then the workflow is stopped. Why?

Because you cannot change a drill bit. When the drill chuck key is lost without a trace, there is only one thing – to buy a new one.

How Does Drill Chuck Work?

Before we understand why everyone beats the alarm when they lose the key of the cartridge, let’s understand what task the cartridge performs.

So, the chuck is a special mechanism, which fixes a bit in the drill machine between the jaws (the cartridge has jaws).

In this regard, distinguish several types of the chuck.

You can meet split-frame chuck, jaw chucks (2 pieces, 3 or 4 pieces).

Those chucks that have jaws work the same regardless of the number of jaws. The chuck directs the movement of the jaws towards each other or in different directions.

The nut rotates and is blocked by teeth on the jaws. When it happens, the jaws move forward or backward. So, the chuck moves the jaws, and the jaws move the shell.

The movement of the jaws occurs when you turn the chuck. If you turn the chuck clockwise, the jaws are assembled, and the bit is fixed.

Conversely, if you turn the chuck counterclockwise, the jaws open and release a bit.

The key gives a greater torque to the chuck, as it clamps the jaws tightly and gives a good grip with a bit that does not slip and does not feel free between the jaws.

What is Drill Chuck Size?

Drill Chuck Sizes - What Chuck Key Do You Need for Better Work (1)
If you have a drill or a drill press, then probably you already know what the size of the chuck is. It is the diameter of the shank that holds the chuck.

It is important to know that this diameter is the maximum.

The shanks are hexagonal and are measured by squares. You can measure the diameter of the shank from any point along the circumference.

As for the capacity of the chuck, it is the maximum shaft of the drill that is between the open jaws of the chuck.

Both capacity and size will be useful to you when choosing a bit. The size of the bit must match the size and capacity of the chuck so that the chuck will hold the bit.

So, if we proceed from standard indicators, a 13 mm chuck will hold a bit with a shank size of 13 mm (or 1/2 inch).

What Chuck Size Do I Need?

When choosing a chuck of the right size, one must proceed from a simple rule:

The larger the size, the bigger the shank.

If you plan to use large bits, then choose a larger chuck.

Generally, a chuck does not have a wide range of sizes, but only two: 10 mm (3/8 inches) and 13 mm (1/2 inch).

But what if you need to drill a hole whose diameter will be larger, say 20 mm?

For this, you can do boring to expand the hole.

How to Size Chuck Keys

Determine the size of the chuck keys is also not difficult. It can be done in three steps.

Step 1:

Look at the cartridge and the bit and the engraved figures. The bit size will vary between 1/4, 3/8, 1/2 inches and so on.

Step 2:

Now measure the diameter of the hole on the chuck. You can do this with a ruler.

Step 3:

Now write down the bit size and the size of the cartridge hole and go with these measurements to the store to buy the required key.

What Chuck Key Do You Need

To choose a chuck you need to consider the size, durability, and type.


Size is important for several reasons.

For example, you use a 3/8-inch chuck and it will work for weak and not very strong drills.

A chuck of the same size cannot hold a bit larger than 3/8 inch. The problem is that most drives require a 1/2-inch chuck, but this cartridge size requires a powerful drill.

Therefore, if you choose a drill and you need a powerful drill, it is better to choose in favor of a 1/2-inch chuck.


Size is an important indicator, but it does not mean anything when the chuck is not durable. The length of the service will tell you the design.

Look at what material the chuck is made of. Some parts can be metal or plastic, sometimes you can meet a symbiosis.

Plastic parts are not always bad, it can be a quality ABS.

In addition, some chucks have several teeth to keep the bits (usually 3 teeth). Teeth can also fail you, especially if it moves or breaks.

But even the broken teeth of the chuck will work, but it began to hold a bit (especially under high pressure). It will be careful with the material and teeth when choosing a cartridge.

Keyless Chuck?

Many people say:

“In order not to lose the key of the chuck, buy a keyless chuck.”

What is it?

It is a small tool that is used to change bits into a chuck.

Most of the drills of any type are keyless and it is good because you can change the bit without additional tools and quickly.

All you need is to rotate the chuck with your hand, loosening or tightening your teeth to remove or insert a bit.

A couple of turns and you can get to work.

Why do people still choose a chuck with a key? Therefore, it is intended for super-powerful tasks, where the keyless chuck cannot cope.

The Most Common Types of Drill Chucks

Drill Chuck Sizes - What Chuck Key Do You Need for Better Work (2)

Chuck Key

It is what we are talking about today. It requires the use of regular bits, and the key is used to open and close the cartridge.

The key is used to tighten a bit. But you must be careful not to lose the key.

Keyless Chuck with Double Sleeve

This type does not require the use of a key but uses conventional drills. And the chuck control requires two hands because it has a double sleeve.

Single-leaf Keyless Chuck

This type also does not require a key to set the bit. And in my opinion, this is the most convenient option for installing a bit. You only need to turn the chuck to open and close the jaws.

SDS Chuck

Such a chuck works only with drills bits SDS. It is useful in working with wood and metal. But you need a special SDS cartridge adapter. This adapter will allow you to use ordinary bits.

Sliding Frames

This chuck has sliding frames on the brackets. A similar frame of the bracket is divided in half in the place intended to hold the bit.

To tighten a bit into the chuck you need a knurled screw (sometimes a nut).

It is enough to pat the clamp, turn the head (or nut) clockwise. Then the bit will be free. And vice versa, turn the bracket counterclockwise to fix the bit.

With this type of chuck, you can use Auger bits, which have square shanks.

Auger bits will help ease the grip since the sliding frame cannot grasp the round shank.

2 Jaws Chuck

This chuck has 2 jaws that hold a bit. The jaws have a cut-out notch that looks like the one that the sliding frame has.

A chuck with 2 jaws is also designed for square bits.

3 Jaws Chuck

This chuck has 3 jaws and is the most popular type. The reason is that the 3-jaw chuck is suitable for fixing square and round bits.

4 Jaws Chuck

That is also convenient to use because 4 jaws can hold both square ones, as well as round bits.

What is a self-centering cartridge?

Perhaps you have often heard of a self-centered bullet. This chuck has jaws that are inside and have the same speed.

“Self-centering” means that the bit is fixed in the center of the chuck. The difference is that usually a bit is kept from the center of the chuck.

Hand drills always have a self-centering chuck, regardless of the number of jaws.


Maybe the keyless drill chuck is more convenient, but we are here to discuss the chuck with the key. It is also convenient, but the key tends to get lost. This is the main problem. So you should have deep knowledge about drill chuck sizes.

Therefore, you must find a place to store the key of the chuck. The drill is not a suitable place, and locked chucks always require the use of a key to make a turn of the sleeve.

Determine the place where the key will always be and then the chuck with the key will lose the main minus.

Also Read:

1. How to Make Money from Woodworking in Your Own Garage
2. Must have Apprentice Electrician Tools List


  • How Does Drill Chuck Work?
  • What is Drill Chuck Size?
    • What Chuck Size Do I Need?
    • How to Size Chuck Keys
    • What Chuck Key Do You Need
    • The Most Common Types of Drill Chucks
  • Conclusion


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