What are the main characteristics of a key?

In this article, we are going to explain what keys are, how they're made, common applications for keys, as well as the benefits of using them. Whether you're an engineer, technician or just curious about how these small parts work, you're in the right place! Let us show you around the fascinating world of keys.

What is a key?

Keys are an essential mechanical part for transmitting motion in various industrial applications. They are used to rotate two parts, such as a shaft and a pulley or a gear, allowing the transmission of force and movement. There are several different types of keys, such as rounded-end keys (type A), straight-end keys (type B), keys with one straight end and one round end (type C), as well as gib head keys and Woodruff keys.

Choosing a material for producing keys

The process of manufacturing keys can differ according to the needs and technical specifications of each application.

Most keys are made from resistant materials such as carbon or stainless steel, but they can also be made from non-ferrous metals such as brass or bronze.

The material grade and sizing depend on what's needed for the application, e.g.:

• Size of the shaft
• Size of the pulley or hub
• Forces to be transmitted
• The application environment.

Here at Gardette Industrie, we manufacture our keys from materials such as:

• Medium-hard steels
• Heat treatment steels
• Stainless steels
• Exotic materials (high-alloy steels, complex stainless steel, Hastelloy/Monel/Inconel nickel alloys...)
• Or any other material that could meet the client's needs.

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How are keys made?

Cold drawing

The first step in manufacturing keys is choosing a material. This will depend on the application you have in mind.

At Gardette, we are the only manufacturer in the world with our own cold rolling, cold drawing and heat treatment plant. This equipment allows us to manufacture a wide variety of standard and special profiles in various materials such as steel, stainless steel, aluminium and copper / nickel alloys.

Cutting

Once the material has been chosen, we cut it to the desired length and begin machining keys using our special machines equipped with cutting tools such as saws or milling machines. Here at Gardette, this stage is carried out in our dedicated cutting department. Type B keys (straight-ended keys) are produced using cutting or sawing machines. In the case of type A keys, or any other keys with complex shapes at their tips, machining is used to achieve the two rounded ends and the desired length using special shaping tools and our unique technologies developed specifically for this purpose.

The perfect finish

At Gardette, we also offer a wide range of finishing processes. Our fleet includes numerical control (NC) machining centres, robotic systems, as well as a dedicated grinding area (flat surface and double disc grinding) in order to ensure highly precise tolerances or roughness, depending on the client's specifications.
Moreover we have a very long calibration area that enables us to carry out operations such as stock squaring, shoulders and gradients on the parts.

Tribofinishing

We also operate a fleet of state-of-the-art vibratory finishing machines to carry out various deburring finishing processes and ensure that our products are of an optimal quality.

Vibratory finishing is an important step in improving the quality and surface finish of parts. It can be used to:

• Get rid of burrs
• Improve surface finish / roughness
• Stretch out sharp edges, improving their appearance and functionality.

Here at Gardette, we use two vibratory finishing techniques: vibration via vibrating bowls and centrifuging via spinning bottoms. The choice between vibration via vibrating bowls and centrifuging via spinning bottoms should be made based on the characteristics of the parts to be treated, your desired finish and the requirements of the manufacturing process.

The different treatments

Once the key has been manufactured, it can undergo a surface or heat treatment to improve its appearance, as well as its resistance to corrosion and wear & tear.
At Gardette, we offer customers a wide range of surface and heat treatments.
The most common surface treatments are:

• Zinc coating
• Burnishing
• Phosphatising
• Painting

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We also offer the following heat treatments:

• Quenching
• Tempering
• Annealing.

We are committed to providing tailor-made solutions to meet the needs of our customers, using cutting-edge techniques and ensuring optimal treatment processes to ensure customer satisfaction.

Quality

The final step in our process is to thoroughly assess the key. During production and once the manufacturing operations have been completed, we ensure through meticulous checks that the key meets the utmost quality standards. Our qualified technicians use state-of-the-art, high-precision measurement tools to check dimensions, tolerances, and other critical specifications to make sure that every key that leaves our workshop is fully compliant. At Gardette, quality is at the core of what we do.

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What are keys used in?

Keys are commonly used to transmit the power of rotation from a shaft to a rotating part, such as a pulley, a gear, or a gear wheel. They are used in various industrial machines, such as motors, machine tools, manufacturing equipment and more. Keys can also be used in specific applications such as power transmission systems for conveyors, lifting equipment, lifting equipment, transport equipment, agricultural machinery, etc.

At Gardette, we work closely with industries such as the automotive sector, civil and military aeronautics, nuclear, mould manufacturers, motors and pumps.

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What advantages do keys offer?

Keys have many advantages compared to other mechanical fasteners such as cable ties or welding. These advantages include:

• High torque transmission: Keys are designed to transmit high torques in mechanical assemblies. For example, a 25mm-wide key can transmit a torque of over 700 Nm, making it a solid option for applications where high torque transmission is required.

• Robustness & stability: Keys provide a robust, stable connection between the assembled elements, which can be important in applications requiring high precision and dimensional stability.

• Durability: Keys are typically made of treated or stainless steel, making them resistant to corrosion, wear & tear and other types of damage, which can contribute to extended assembly life.

• Ease of installation: Keys are relatively easy to install and replace within an assembly, with simple and well-established assembly procedures.

• Widely available: Keys are commonly used and available in many different sizes, shapes and configurations, making them an easily accessible option on the market.

• Standardised design: Keys are manufactured according to official design and manufacturing standards, making it easy to integrate them into existing assemblies or new designs.

In short, keys are essential components in mechanical systems to ensure that forces are transmitted efficiently and safely. Appropriate use, regular monitoring and adequate maintenance are required to ensure they function correctly and to prevent any potential failures.