Centre Drill Bits

Centre Drill Bits Explored

Centre drill bits are made primarily from high-speed steel (HSS) or carbide, and they are specifically designed to create small, accurate pilot holes in a workpiece which are then ideal for a cutting drill. By doing so, they guide larger drill bits and cutting tools, helping you to get a smooth and error-free machining process as a result. But how do you know which centre drill bit is right for you?
Well, in this drill bit guide to Centre bits, we will give you an in-depth look at centre drill bits, their types, uses, and benefits, to help you understand their role in various applications and, importantly, which one is right for you and your tool kit, and how to get the most out of them as well.

What Are Centre Drill Bits?

Definition: Centre drill bits are specialised cutting tools used in metalworking to create precise pilot holes or starting points for larger drills. As a result, they have a short length and a double-ended design with a conical tip and a small cylindrical portion.

The conical tip then helps you in creating accurate positioning, while the cylindrical part creates the pilot hole. Consequently, this design reduces wandering and helps you get the best alignment when drilling deeper holes.

Centre drill bits are then often used to prepare workpieces for turning operations on a lathe by creating a conical hole, which can then accommodate the lathe's live centre - which rotates with the drill bit - or dead centre - which does not - for example.

Types of Centre Drill Bits

Not all centre drill bits are equal; for instance, there are several types of these drill bits available, each of which is well suited to specific applications and materials.

For example, here you can have:

HSS Centre Drill Bits

HSS Drill bits are made from High-Speed Steel, a strong and durable material that can easily withstand high temperatures without losing hardness. As a result, these are suitable for general-purpose applications and are resistant to wear as well - making them a very cost-effective choice for many machining tasks as a result.

HSS bits are also very adaptable and can handle a variety of materials, including mild steel and aluminium to name just two for example.

Carbide Centre Drill Bits

Carbide Centre Drills are then ideal for working with harder materials like stainless steel and cast iron, as these are made from a compound of carbon and tungsten. As a result, these drill bits give you a lot more improved durability and precision as a result of this.

They also maintain their sharpness for longer than HSS bits do as well, but are more brittle - requiring careful handling to prevent breakage due to this.

Combination Centre Drills

Combination centre drills can then incorporate both a drill bit and a countersink in one tool. This design, for example, allows you to perform multiple operations with a single tool, making them great for various applications as a result.

They are also particularly useful when you need to create a pilot hole and a chamfered edge simultaneously - thanks to their specific countersink angle.

Micro Centre Drill Bits

Micro centre drill bits are then more perfect for fine, detailed work where precision really is needed. As a result, these can be more commonly used in jewellery making and intricate machining, as these tiny drill bits allow for accurate drilling in small or delicate components.

Applications of Centre Drill Bits

As you can see centre drill bits are then ideal in various industries due to their ability to provide you with a lot of precision and alignment.

For example, these can consist of:

Creating Pilot Holes

Centre drill bits are primarily used to create pilot holes for larger drill bits, ensuring accurate positioning and alignment can then occur.

Lathe Operations

These drill bits also help to prepare workpieces for lathe machining by creating conical holes to hold live or dead centres.

Reducing Drill Wander

They are also ideal to help to reduce the wandering of larger drill bits by providing you with a more precise starting point.

Countersinking

Centre drill bits can be used for shallow countersinking in metal and other materials as well.

Engraving Setup

These bits create starter points for engraving or precision milling operations to then continue.

Sheet Metal Drilling

Centre drill bits are also ideal for marking starter holes in sheet metal without deformation.

Bolt Hole Preparation

They can also help you in accurately starting holes for bolts and threaded fasteners as well.

Design Features of Centre Drill Bits

Centre drill bits come with some very unique features that really help with how effective they are.

For instance, here, these features can consist of:

Body Diameter

The body diameter of a centre drill bit will then determine its overall strength and rigidity. For example, a properly chosen body diameter for the application you need it for will help you to get the most stability during your drilling - while also reducing vibrations and improving precision in the process at the same time.

The body will also affect the compatibility with the drill chuck and the workpiece material being machined as well.

Size

The size of a centre drill bit will then influence what applications it can be used for and the type of holes it can create. For example, choosing the correct size here will give you the best overall performance, help to prevent tool breakage, and maintain its alignment when transitioning to larger drill bits for deeper drilling operations as well.

Cutting Diameter

The cutting diameter is then key for achieving the desired hole size, as this parameter will then determine how much material the drill removes, and it will also impact the accuracy of the pilot hole that is created as well.

A proper cutting diameter selection will then give you a precise start for subsequent machining processes as well.

Pilot Diameter

The pilot diameter size then affects the alignment of larger drill bits by providing a guiding hole for them. Consequently, this helps any subsequent drilling operations proceed smoothly and with a high level of accuracy, preventing errors such as misaligned or off-centre holes from being created.

Body Diameter

The body diameter of the bit then helps with the strength and durability of the centre drill bit that you then get. A larger body diameter, for instance, will give you a much better resistance to deflection during use, all while giving you more accurate and consistent results in various machining tasks as well.

Overall Length

The overall length then determines the reach and usability of the drill bit in different applications. For example, here, a properly chosen length gives you the accessibility you need in tight spaces while maintaining your stability as it does so during your drilling operations. We also list these out in both imperial and metric sizes above for you as well.

An excessive length can also lead to excess vibrations, while too short a length limits the drill bits' use cases as well.

Flute Design

The drill bits flute design is also ideal in centre drill bits as it determines your chip evacuation and cutting efficiency. For example, properly designed flutes reduce heat buildup and ensure that you get smooth material removal as well, which in turn improves your overall precision.

Here, optimised flutes also improve the bit’s lifespan as well by minimising the drill bits' wear and enabling clean, consistent cuts in various materials to then occur.

Body Shape

Another feature to consider is the body shape of a centre drill bit, as this then influences its stability and especially its durability during drilling. For example, a sturdy, short body will reduce the amount of vibrations it produces, giving you a lot more accurate pilot holes in turn and reducing the risk of wandering as well.

The design here will also support better torque transmission as well, making it even more reliable for high-precision machining tasks like lathe operations, for example.

Point Angle

The point angle of the drill bit is also used to determine the bit's cutting performance and suitability for specific materials. A properly chosen point angle, for example, will give you a more efficient penetration, while it reduces the thrust force required - preventing material deformation from then occurring.

Different angles are also optimised for various tasks as well, such as creating clean pilot holes or countersinking, for example.

What Are The Different British Standards (BS)?

When it comes to these drill bits, they come with a number of different BS certifications. For example, these are important to know, due to:

BS 00 - Small Drill Bit Dimensions

BS 00 standard, for example, defines specifications for small drill bits, ensuring that they give you accurate dimensions and functionality for more fine, precision drilling tasks, especially in delicate materials where consistency is critical.

BS 1 - Basic Dimension Standards

BS 1 then specifies the fundamental dimensions for centre drill bits, ensuring that you get ones that are compatible across various applications, preventing errors in machining setups caused by mismatched tools to then occur.

BS 2 - Materials and Composition

BS 2 then governs the materials used in the manufacturing of centre drill bits, ensuring they are consistently durable and give you the performance you need by requiring high-quality steel or alloys that can withstand stress and wear.

BS 3 - Thread Standards

This standard then covers threading specifications, which are important for drills used in conjunction with threaded components, as this helps to give you the correct fit and functional reliability during use that you would expect.

BS 4 - Conical Angle Specifications

BS 4 then defines the conical angles for centre drill bits, meaning that you are sure of the precision it will give you in your machining processes and compatibility with standard lathe centres or other components as well.

BS 5 - Tolerances and Accuracy

BS 5 then sets out tolerances for drill bits, ensuring that they are consistent in size and accurate across batches as well. This is really ideal for achieving precise machining results.

BS 6 - Surface Finish

BS 6 then specifies the required surface finish for centre drill bits, which in turn helps to reduce friction and improves your performance during operation - which prolongs your tool life as a result.

BS 7 - Performance Testing

This standard then outlines the testing procedures to evaluate the performance of centre drill bits, ensuring they meet the necessary criteria for strength, durability, and precision.

BS 8 - Safety Requirements

BS 8 then establishes the safety standards for the manufacture and use of centre drill bits - which in turn minimise the risks during you using it and also helps to promote safe handling practices as well.

How Do Centre Drill Bits Differ from Regular Drill Bits?

Unlike regular drill bits, centre drill bits are shorter and more rigid, as they are designed specifically for creating pilot holes.

Their sturdy construction then reduces drill wander — a common issue with longer, more flexible drill bits. This precision then gives you more accurate alignment, making centre drill bits really indispensable in high-precision machining. Thanks to this, even minor deviations can lead to significant errors.

They also differ in their cutting-edge design and point angle as well, as these are more optimised for starting holes rather than drilling to depth.

Materials Used in Centre Drill Bits

The choice of material used in the construction of the centre drill bits will also impact its performance and suitability for different tasks as well

For instance, here, you have to factor in the following:

High-Speed Steel (HSS)

HSS bits are cost-effective and adaptable, and they are suitable for general-purpose drilling in softer metals. For example, they offer you a good balance between toughness and hardness here.

Carbide

Carbide bits are then harder and more wear-resistant, which is ideal for heavy-duty and high-speed applications involving hard materials, especially as they maintain a sharp cutting edge for longer but are more brittle.

Coated Centre Drills

These drill bits can also be coated with materials like titanium nitride or cobalt, which then improves their durability and heat resistance properties - which in turn extend the tool's life and performance, especially in demanding applications.

How to Choose the Right Centre Drill Bit?

As you can see, there is a lot of consideration when asking this question. Consequently, selecting the appropriate centre drill bit depends on several factors such as:

Material Compatibility

Here, you want to make sure that the bit material is suitable for the workpiece to prevent premature wear or damage.

Size Requirements

You also want to choose a bit that matches the desired pilot hole size to achieve the correct alignment. For example, sets like a Centre Drill Set or multi PC Set offer you a range of sizes to choose from, over being reliant on the one-bit size.

Coating Options

You also want to consider coated bits for added durability, especially when working with abrasive materials or at high speeds.

Hand Orientation

Some applications may also require left-hand or right-hand drill bits, particularly when dealing with specific machinery or techniques we should note.

Series Length

Long series centre drills are also available for applications requiring deeper pilot holes as well if required.

Steps to Use a Centre Drill Bit Effectively

Choosing the right drill bit is one thing; using it is another. Consequently, we have put this section together to help you get the best results from a centre drill bit.

For instance, here you should:

Prepare the Machine

Firstly, you want to make sure that your drilling machine or lathe is properly set up and that all components are tightened and aligned. Check that your power tools or hand tools are in good working order.

Secure the Workpiece

Use clamps or a vice to hold the workpiece firmly, preventing movement during drilling.

Select the Correct Chuck

You also want to use a suitable collet chuck or drill chuck to hold the centre drill securely.

Drill with Care

When you start, you also want to start at a low speed to maintain your control and then gradually increase when necessary, but make sure that you apply steady, moderate pressure throughout.

Monitor Progress

You also want to watch for signs of overheating or misalignment that may be showing, and when they do, pause if adjustments are needed.

Follow Safety Protocols

You also want to wear the correct Personal Protective Equipment (PPE) gear like safety glasses and gloves, and keep your workspace clear of obstructions as you do so.

Can Centre Drill Bits Be Used For Wood?

They are primarily designed for metals. For wood, you should consider using standard wood drill bits or pilot drill bits as these may give you much better results here.

How Do I Help to Prevent a Centre Drill Bit From Breaking?

You can use the correct drilling speed, apply moderate pressure, and ensure proper alignment to help prevent breakage. You should also avoid side-loading the bit and ensure the workpiece is securely clamped as well, where needed.

What Size Centre Drill Bit Should I Use?

You want to select a size based on the desired pilot hole diameter for your specific application really.

Are Carbide Centre Drill Bits better than HSS?

Carbide centre drills are more durable and better for hard materials, but they are also more expensive. HSS centre drills on the other hand are more cost-effective as well we should note.

---

Centre Drill Bits Overall

As you can see in this centring guide to the right bits for you here, centre drill bits are indispensable tools for achieving precision in machining tasks, no matter if you are looking for a Dormer A225 hss centre drill or a solid carbide one. As a result, we hope that you now understand their different types and applications and how to use them effectively, as this can significantly enhance the quality of your work when you do.

So, whether you are a professional machinist or a hobbyist, choosing the right centre drill bit for you and then maintaining it properly will ensure accurate results and prolong the life of your tools as a result, if you are still not sure, give our customer service team a call, and we will be happy to help you find the right bit for your application. After all, our friendly team is here to help.

Contact Customer Support

If you are still not sure which centre drill bits is right for you or you need help, then for further information please contact our team, and we will be happy to help you understand which ones are perfect for you and your team.

Standard Delivery Options

We have also extended our delivery service and ordering hours to offer you free next-working-day delivery, making your shipping experience even easier.

Place your order online by 7 p.m. and choose the delivery charge that suits you - including next-day dispatch - to ensure you get a timely, UK mainland hassle-free delivery of your products.

Standard free UK delivery is also available for all products ordered within the specified time, with free shipping and a good returns policy for certain items as well.

Who Is MSC Industrial Supply Co.?

Here at MSC Industrial Supply Co., we are a leading supplier of industrial tools, equipment, and maintenance supplies across the United Kingdom. We offer trade accounts, a vast selection of new products, and free next-day delivery on eligible orders.

Our extensive range includes everything from hand tools and power tools to specialised hole-making equipment like blacksmith drill bits, core drills, and machine reamers, to name just a few.

As a result, we can provide you with a comprehensive selection of products, including:

• Blacksmith Drill Bits
• Countersinks
• Step Drill Bits
• Masonry Drill Bits
• Hand Tools
• Indexable Insert Drills
• Cutting Tools
• Abrasives
• Power Tools
• Reamer Tools
• Safety Equipment

As a result, we serve a wide range of industries, from manufacturing and engineering to maintenance and beyond. Consequently, our commitment to providing quality products and exceptional customer service makes us a trusted partner for all your industrial needs.

With our knowledgeable customer support team and technical assistance available Mon-Fri, we ensure you have the support you need to succeed.