Key Locking Thread Inserts

4.1 Product Introduction

Key locking thread inserts are professional fasteners developed to solve the problems of easy loosening and damage of threaded connections in industrial equipment. Featuring a core mechanical interlocking structure of locking keys and external grooves, different from the single connection mode of ordinary thread inserts, the locking keys will be directly clamped into the wall of the base threaded hole after installation, forming an irreversible locking effect. It fundamentally solves the problem of thread loosening caused by vibration, impact and sudden temperature changes, and is suitable for both static and dynamic load working conditions.

This key locking thread insert adopts a composite processing technology of cold heading and precision turning, with accurate internal and external thread profiles and uniform groove positioning. The locking keys are made of high-toughness alloy steel, seamlessly connected with the insert body, with excellent compression, bending and wear resistance, without deformation or falling off during long-term use. The product is divided into two series: standard wall thickness and ultra-thin wall thickness, and non-standard specifications can be customized according to customers' base material, installation space and load requirements to meet personalized industrial needs.

Core Advantages

• Mechanical rigid anti-loosening: Locking keys are clamped into the base to form interlocking, without gluing or elastic loss. The anti-loosening effect is durable and stable, suitable for equipment working conditions with long-term vibration.
• Multi-scenario thread repair & reinforcement: It can not only repair stripped, damaged and worn internal threads, but also be pre-installed on newly manufactured workpieces to strengthen the threaded connection strength, achieving two functions in one product.
• Strong material adaptability: It can be installed on base materials of different hardness such as steel, aluminum alloy, copper and engineering plastics without additional surface treatment of the base.
• No gap after installation: High precision of thread meshing, seamless fit with the base after installation, effectively reducing the shaking and displacement of the connection part and improving the operation precision of equipment.
• Excellent weather resistance: Multiple anti-corrosion treatments on the surface, applicable to harsh environments such as humidity, high temperature and corrosive media, without rust or aging.

4.2 Product Parameters 

Core Technical Parameters of Key Locking Thread Inserts

Dimension Table of Main Specifications for Metric Standard Wall Thickness Key Locking Thread Inserts

Dimension Table of Main Specifications for Metric Ultra-thin Wall Thickness Key Locking Thread Inserts

4.3 Product Installation

Standardized Installation Steps

1. Pre-machining Preparation

 According to the selected specification of key locking thread insert, match a special drill bit for pre-drilling, ensuring the hole wall is smooth without burrs and the verticality ≤0.05mm; if the base material is high-hardness steel, the drill bit speed can be appropriately reduced to avoid edge chipping of the hole wall.

2. Tapping with Special Tap

 Use the special non-standard tap matched with this product to tap the pre-drilled hole. Cutting fluid can be applied during tapping to ensure the integrity of the thread profile; after tapping, clean the iron chips in the hole with compressed air, and proceed to the next step only when there is no residue.

3. Insert Clamping and Positioning

 Sleeve the key locking thread insert on the positioning shaft of the special installation tool to ensure the coaxiality of the insert and the tool is consistent, with the locking key end facing down to avoid installation failure caused by clamping skew.

4. Screwing in and Locking

 Align the installation tool vertically with the base threaded hole, screw the insert in clockwise at a constant speed until the top of the insert is flush with the base surface; continue to apply a constant torque clockwise to make the locking key clamp into the base hole wall under pressure. Stop applying force when a "click" sound is heard, indicating the completion of locking.

5. Post-installation Inspection

 Inspect the accuracy of the internal thread of the insert with a plug gauge, and shake the insert by hand to confirm no loosening. If installed in a through hole, check the clamping state of the locking key on the other side of the base to ensure qualified installation.

Installation Taboos and Notes

1. Forbid tapping with ordinary taps: Special taps are precisely matched with the external thread of the insert. Ordinary taps will lead to excessive thread meshing gap, affecting the connection and anti-loosening effect.
2. Forbid reversing the tool during the entire installation process: Even if the insert is found to be skewed, the insert must be completely unscrewed and re-clamped. Reversing will cause the locking key to bend and the insert to be scrapped.
3. When installing the ultra-thin wall thickness series inserts, the torque must be controlled within the specified range. Excessive torque will cause the insert to deform, and it is recommended to use a torque wrench for operation.
4. After installation in corrosive environments, a small amount of anti-rust sealant can be applied at the joint of the insert and the base to improve weather resistance without affecting the thread connection function.
5. For batch installation, it is recommended to calibrate the installation tool regularly to ensure the coaxiality of the positioning shaft and avoid the decrease of installation accuracy caused by tool wear.

4.4 Product Application Introduction

Industrial Applications and Scenarios of Key Locking Thread Inserts

With the dual characteristics of mechanical rigid anti-loosening and high-strength connection, key locking thread inserts have become the preferred solution for threaded connections in industrial manufacturing. They not only solve the industry pain point of easy loosening of traditional threaded connections, but also realize the rapid repair of damaged threads, greatly reducing equipment maintenance costs and downtime. They are widely used in various industries with high requirements for connection reliability and stability.

In the field of transportation equipment manufacturing, they are applied to automobile engines, gearboxes, chassis suspensions, bogies and body connections of rail transit vehicles, ship engines, deck equipment and other parts, resisting the continuous vibration during vehicle driving and ship navigation, and avoiding safety failures caused by thread loosening. In the field of aerospace and military industry, they are matched with aero-engine parts, aerospace equipment structural parts, core components of military equipment, maintaining absolute stability of threaded connections under extreme working conditions such as extreme temperature, high pressure and strong vibration. In the field of precision machinery and intelligent manufacturing, they are used in CNC machine tools, robot joints, automated production line equipment, improving the operation precision and stability of equipment, and reducing equipment deviation caused by thread gaps. In the field of new energy and engineering machinery, they are adapted to wind power equipment, photovoltaic brackets, hydraulic systems of engineering machinery, mining machinery parts, achieving long-term anti-loosening in harsh outdoor and field environments and reducing the frequency of later maintenance.

In addition, key locking thread inserts can also be applied to electronic communication equipment, medical precision instruments, heavy building components and other scenarios. Whether it is the pre-installation of thread reinforcement for new products or the thread repair of old equipment, they can provide highly adaptable and reliable solutions to meet the threaded connection needs of different industries and working conditions.