CNC drills are tools designed to create accurate holes in various materials, including metals, composites, wood, and masonry. Analyzing the application where the drill will be utilized is essential to start the design process effectively. This means not only identifying the material you will be drilling into but also considering crucial factors like the desired size of the holes and the operational conditions—such as optimal speed, feed rate, and the use of coolant. Analyzing and researching industry standards and competitive tools can provide valuable insights that help ensure superior performance while addressing any unique challenges you might face.

At Baucor, we bring our extensive expertise to assist you throughout the design process. Our team's deep understanding of material properties, drill geometry, and finishing options ensures that we can guide you in selecting the appropriate material, geometry, and coating for your application, exceeding your expectations and delivering superior performance.

2. Defining the drill’s specifications:

The next step is to define the key geometric features that determine the drill’s performance: 

1. Drill type:
   Selecting the appropriate drill type is crucial as it will define the base design of the drill and what it can do. For example, gun drills are ideal for deep-hole drilling due to their superior chip evacuation capabilities, while step drills allow for drilling multiple diameters in a single operation. Other options, such as masonry drills, are designed to manage abrasive materials like concrete and brick. At Baucor, we offer a wide range of drills. For more details, check the section below titled “Drill types‎.”
   
   
2. Point angle:
   The point angle affects the drill’s ability to penetrate the material and influences chip formation. Standard angles include 118° for general-purpose drilling and 135° for more rigid materials. Split points are beneficial for reducing wandering and improving accuracy, especially when starting a hole.
   
   
3. Flute design:
   Include flute length and helix angle for optimal chip removal and coolant flow. Helical flutes are ideal for softer materials as they efficiently evacuate chips, while straight flutes are better for brittle materials like glass or ceramics. The helix angle (30° to 45°) should match the cutting forces and material properties.
   
   
4. Diameter and length:
   Define the diameter and length to ensure compatibility with CNC machines and the intended application. Extra-long drills are designed for deep holes but require added rigidity to prevent deflection. Reduced shank drills allow for larger-diameter cutting with smaller tool holders.
   
   
5. Cutting edge configuration:
   The cutting edge geometry determines the drill’s performance in cutting force, heat generation, and surface finish. For example, chamfered cutting edges provide a smoother entry, while sharp edges ensure efficient material removal in softer materials.
   
   
6. Core thickness – The core thickness affects the drill’s strength and resistance to breakage. Thicker cores are suitable for rigid materials but may compromise chip evacuation, requiring adjustments to flute design.
   
   
7. Margin Design:
   Margins are the narrow bands of contact between the drill and the material. An adequately designed margin minimizes friction and improves hole quality by stabilizing the drill during operation.
8. Drill mounting:
   The mounting mechanism ensures stability and secure operation during high-speed machining. Features like clamping, bolting, and quick-change capabilities enhance efficiency while maintaining precision. Robust mounting geometries withstand operational stresses and are compatible with diverse CNC machine setups. Refer to the table below (Tool mounting) for more details.
   
   
9. Drill material:
   Choosing the right material is crucial for performance and longevity. High-speed Steel (HSS) offers versatility and cost-effectiveness for general applications, while carbide excels in high-speed operations on hard materials due to its superior wear resistance. Powdered metal balances toughness and wear resistance, making it ideal for demanding environments.

Drill types: 

Baucor provides various CNC drilling tools, each designed for a specific application.

Below are the drills grouped by type:

A. General Purpose Drills

1. Jobber Length Drills: A versatile option for general drilling tasks, suitable for various materials.
2. Screw Machine Length Drills: Shorter overall length for increased rigidity and precision.
3. Stub Length Drill Bits: These compact drills are ideal for shallow holes and tight spaces.
4. Extra Long-Length Drill Bits: Designed for deep drilling applications with enhanced rigidity.
5. Taper Shank Drills: Suited for heavy-duty industrial applications requiring secure fit.
6. Reduced Shank Drills: Allows larger-diameter drilling using standard tool holders.
7. Large Diameter / Oversized Drills: These are oversized bits for bigger holes where specialized equipment or reduced‐shank designs are not required.

B. Special Drills (Flute Variation & Micro)

1. Double Margin Straight Flute Drills: Enhanced stability and reduced deflection 
2. Straight Flute Drills: Optimal for brittle materials like ceramics and glass.
3. Micro Drill Bits: Designed for precision drilling in delicate and small components.
4. Three Flute Drill Bits: Improved material removal rates and smoother operation
5. Twist Micro Drills: Suitable for high-speed drilling in fine applications.

C. Wood Drills

1. Auger Drill Bits: Effective for drilling deep, clean holes in wood and softer materials.
2. Forstner Drill Bits: Creates smooth, flat-bottom holes with minimal tear-out.
3. Plug Cutter Drill Bits: Creates plugs for concealing screws and other applications.
4. Spade Drill Bits: Wide blades for rapid material removal in softer materials.
5. Spur Point/Brad Point Drill Bits: Excellent for clean, precise holes in wood

D. Masonry & Tile Drills

1. Masonry Drill Bits: Built to withstand abrasive materials like brick, concrete, and stone.
2. Glass/Tile Drill Bits: These bits are designed for drilling through brittle materials such as glass and ceramics without cracking.

E. Deep‐Hole Drills

1. Deep Hole Drills: Engineered for extended reach and high accuracy in deep drilling applications.
2. Gun Drills: Ideal for high-precision deep-hole drilling

F. Hole Preparation Drills

1. Spot Drills: Designed to start holes with precision and accuracy
2. Center Drill Bits: Creates accurate pilot holes for lathe operations.
3. Pilot Point Drills: Ensures precise starts and reduces wandering.

G. Hole Finishing Drills

1. Step Drills: Multiple-diameter holes in a single operation.
2. Countersink Drill Bits: Used for creating beveled edges for screws.
3. Counterbore Drills: Precision cutting for creating flat-bottom holes.
4. Drill Chamfer Tools: Combines drilling and chamfering in one operation.

Before manufacturing, confirming the design is essential. Techniques like finite element analysis (FEA) or rapid prototyping (e.g., 3D printing) help ensure the drill’s geometry and material selection are fine-tuned for performance. Iterative testing and adjustments based on feedback improve durability, functionality, and efficiency.

Designing drills involves precise attention to geometry, material, and coatings tailored to specific applications. Following this design guide, you can achieve a drill design that maximizes performance, extends tool life, and meets industry standards. Contact Baucor today to develop the perfect CNC drill for your machining needs.