drill bit

Drill bit is a tool used to drill holes in various materials such as metal, wood, stone, concrete, etc. It is widely used in industrial manufacturing, construction, machinery maintenance, home decoration and other industries. Its performance directly affects drilling efficiency, accuracy, and surface quality.

1、 Basic structure of drill bit

Regardless of the type, drill bits typically consist of the following core components:

Handle: The part where the drill bit is connected to a drilling rig (such as an electric drill, bench drill, impact drill, etc.), used to transmit torque and secure the drill bit. The common types of shank include straight shank (cylindrical, suitable for small diameter drill bits) and tapered shank (conical, matched with the drill spindle through friction, suitable for large diameter drill bits).

Neck: The transition area connecting the handle and the working part, where some drill bits will be labeled with specifications, materials, and other information.

Work section: The core functional area of the drill bit, including the cutting and guiding parts:

Cutting section: located at the front end of the drill bit, consisting of a main cutting edge, a secondary cutting edge, and a transverse edge, responsible for directly cutting materials.

Guiding part: equipped with spiral grooves (or straight grooves), used to guide the drill bit to feed in the correct direction and discharge the debris generated by cutting out of the hole, while also supporting the drill bit and maintaining the straightness of the drilling hole.

2、 Main types and applicable scenarios of drill bits

According to different processing materials and structural designs, drill bits can be divided into various types, commonly including:

1. Fried Dough Twists bit

Structural features: It is a commonly used type of drill bit, with a spiral working part and two spiral grooves, suitable for most general drilling scenarios.

Applicable materials: metal (steel, cast iron, etc.), wood, plastic, etc.

Classification:

High speed steel Fried Dough Twists drill: low cost, good toughness, suitable for low-speed drilling of general metal and non-metallic materials.

Cemented carbide Fried Dough Twists drill: with good hardness and performance, it is suitable for high-speed drilling and hard metal processing (such as stainless steel and quenched steel).

2. Impact drill bit

Structural features: The head is embedded with a hard alloy blade, and the handle is mostly round or hexagonal, suitable for use with impact drills.

Applicable materials: brittle building materials such as concrete, brick walls, and stone, which rely on the dual effects of impact and rotation to break materials.

3. Flat drill (flat drill)

Structural features: The cutting part is flat, with a simple structure and low manufacturing cost.

Applicable materials: Mainly used for drilling wood, but can also be used for softer metals such as aluminum, but with lower drilling accuracy.

4. Center drill

Structural features: The front end is a conical cutting part used to drill a central hole on the surface of the workpiece.

Function: To locate subsequent drilling, turning and other processes, prevent drill bit displacement, protect machining accuracy, commonly used for shaft parts in mechanical machining.

5. Deep hole drill bit

Structural features: Large aspect ratio (usually exceeding 10:1), with special chip removal and cooling channels.

Applicable scenarios: Used for machining larger scale holes (such as machine tool spindle holes, gun barrels, etc.), requiring a dedicated cooling system to avoid overheating and damage to the drill bit due to poor chip removal.

6. Step drill bit (hole drilling bit)

Structural features: It has a stepped shape with different diameters for each step, allowing for drilling or expanding holes of different diameters at once.

Applicable materials: metal sheet (such as steel plate, aluminum plate), can complete multi-scale drilling without replacing the drill bit, with good efficiency.

7. Woodworking drill bit

Classification and characteristics:

Woodworking Fried Dough Twists drill: similar to metal Fried Dough Twists drill, but with wider spiral groove and good chip removal ability.

Woodworking flat drill: with sharp cutting edges, suitable for drilling large diameter wood.

Countersink drill: used to drill countersunk holes on the surface of wood, allowing screw heads to be embedded inside the material and maintain a flat surface.

3、 Material of drill bit

The material of the drill bit directly determines its hardness, performance, and service life. Common materials include:

High speed steel (HSS): containing alloying elements such as tungsten, chromium, and vanadium, with high hardness (HRC62-65), good toughness, and the ability to withstand certain impacts. It is suitable for processing general metal and non-metal materials and has a moderate price.

Hard alloy: It is sintered from hard phases such as tungsten carbide (WC) and bonding phases such as cobalt (Co), with high hardness (HRA89-93) and much higher performance than high-speed steel. However, its toughness is poor and it is afraid of impact. It is suitable for processing hard metals, high-temperature alloys, stone, etc. and needs to be used with high rigidity machine tools.

High speed steel hard alloy composite: The cutting head is made of hard alloy, and the handle is made of high-speed steel, which balances performance and toughness, and is commonly used for processing medium hardness materials.

Ceramics: High hardness and performance, high temperature resistance (based on actual reports), suitable for processing high hardness alloy materials, but high brittleness and narrow application range.

4、 Selection and usage techniques of drill bits

1. Principle of selection

According to the selection of processing materials: high-speed steel or hard alloy drill bits are selected for metal, woodworking drill bits are selected for wood, and impact drill bits are selected for concrete.

Select according to the drilling diameter and size: straight shank Fried Dough Twists drills are used for small diameter holes, taper shank drills or step drills are used for large diameter holes, and special deep hole drills are used for deep holes.

According to the type of machine tool, ordinary electric drills use straight shank drill bits, bench drills and drilling machines can use tapered shank drill bits, and impact drills need to be equipped with impact drill bits.

2. Usage skills

Reasonably control the speed and feed rate: materials with good hardness (such as quenched steel) should reduce the speed and increase the feed rate; Soft materials can increase the rotational speed, reduce the feed rate, and avoid overheating of the drill bit or rough surface of the workpiece.

Cooling and lubrication: When drilling metal holes, cutting fluid (such as emulsion or engine oil) should be used to reduce temperature, friction, and wear; Wood drilling generally does not require cooling, but attention should be paid to timely chip removal.

Regular inspection and sharpening: After the drill bit wears out, problems such as decreased drilling accuracy and efficiency may occur. It is necessary to sharpen the cutting edge in a timely manner to maintain sharpness; Severely damaged drill bits should be replaced to avoid affecting machining quality and safety.

Anran operation: When using, it is necessary to fix the workpiece and wear protective glasses to prevent debris from splashing and injuring people; The installation of the drill bit should be firm to avoid detachment during high-speed rotation.

5、 Maintenance and upkeep

Clean the debris and cutting fluid on the drill bit in a timely manner after use, keep it dry, and prevent rust.

When storing, it should be classified and placed in the drill bit box or toolbox to avoid collision and compression, and to prevent damage to the cutting edge.

Long term unused drill bits can be coated with rust proof oil to prevent oxidation and corrosion.

In short, selecting the appropriate drill bit and using and maintaining it correctly can effectively improve drilling efficiency and quality, extend the service life of the drill bit, and reduce production costs. In practical applications, it is necessary to comprehensively consider factors such as materials, structure, and machine tools according to specific processing requirements in order to fully utilize the performance of the drill bit.