Knocking-Undercut Anchor Manufacturers

Knocking-Undercut Anchor Manufacturer

As a Knocking-Undercut Anchor Manufacturers, we match product configuration to the application, operating limits, interfaces and acceptance criteria defined for each project.

Jiangsu Aozheng Metal Products Co., Ltd. is a direct Knocking-Undercut Anchor manufacturer and supplier in China. We produce the complete undercut anchoring range for stone cladding, precast concrete, and curtain wall applications. Our factory integrates raw material forming with CNC machining, stamping, and laser processing, giving us full control over dimensional accuracy, material grade, and surface finish. With an annual capacity of 8,000 tons of construction hardware, we supply project-specific anchor configurations to facade contractors, precast plants, and engineering teams worldwide.

The knocking-undercut anchor is a mechanical fixing that expands inside a drilled hole to create a positive undercut in concrete or masonry. It is specified where high pull-out resistance and seismic performance are required, particularly for natural stone, ceramic, and terracotta cladding. Our range includes drop-in and slab-type anchors, each engineered for a defined base material thickness and load class.

Product Range and Application Fit

We manufacture two primary knocking-undercut anchor types, each designed for a specific installation method and substrate condition:

• Drop-in undercut anchor – a continuous-structure anchor that expands on impact. It is used for pre-drilled holes in concrete and masonry where the anchor is set flush or below the surface. Common in structural connections, railing fixings, and heavy equipment mounting.
• Undercut anchor for natural stone slabs – a shallow-embedment anchor with a controlled expansion zone that prevents edge breakout in thin stone panels. It is the standard fixing for granite, marble, and limestone facades where visible mechanical fixings are not acceptable.

Both types are available in stainless steel grades suited to exterior exposure, including A2 (304) and A4 (316) for coastal or industrial environments. We also produce anchors in carbon steel with hot-dip galvanized or zinc plating for internal or temporary applications where corrosion resistance is less critical.

Engineering and Customization

Every project starts with a review of the substrate, panel weight, wind load, and edge distance. Our engineering team uses these inputs to define the anchor diameter, embedment depth, and expansion sleeve length. We routinely customize the anchor geometry to match a specific stone thickness or to fit a non-standard counterbore profile.

For large facade projects, we coordinate the anchor design with the complete undercut anchoring system, including the drilling template and setting tool. We can supply anchors pre-assembled with the required bolts or threaded studs, reducing on-site installation time.

Material and Specification Considerations

Selecting the correct anchor grade depends on the base material and environmental exposure. The following table summarizes our standard material options and typical applications:

We confirm the chemical composition and mechanical properties of each heat through our in-house spectrometer and tensile tester. For critical projects, we provide material certificates and test reports as part of the documentation package.

Quality Assurance and Testing

Our production process follows standardized procedures at every stage, from incoming raw material inspection to final dimensional checks. We operate our own laboratory equipped with a spectrometer, tension tester, and surface inspection tools. Each finished anchor is checked for dimensional accuracy, thread quality, and surface condition before packing.

For seismic or high-load applications, we can perform pull-out testing on representative samples to verify the anchor’s performance in the specified concrete strength. We also provide installation training and setting tool calibration guidance to ensure the anchor achieves its rated capacity on site.

Installation and Maintenance

Knocking-undercut anchors require a accurately drilled hole with a defined diameter and depth. We supply the matching drill bit and setting tool for each anchor size. The anchor is inserted into the hole, and a setting tool is used to expand the undercut. After installation, the anchor is ready for immediate loading, with no curing time.

Maintenance is minimal. For exterior facades, periodic inspection of the anchor heads and sealant is recommended. Stainless steel anchors do not require additional corrosion protection, but we advise avoiding contact with dissimilar metals to prevent galvanic corrosion.

Information We Use to Configure Your Solution

To prepare a precise quotation and technical proposal, we need the following project information:

• Base material type and compressive strength (e.g., concrete grade, masonry)
• Panel or fixture weight and dimensions
• Wind load or seismic design parameters
• Edge distance and anchor spacing
• Required material grade and surface finish
• Installation method (drop-in or slab-type)
• Quantity and delivery schedule

With these details, we can recommend the correct anchor size, provide load data, and supply samples for pre-production testing.

Frequently Asked Questions

What is the difference between a knocking-undercut anchor and a screw-in undercut anchor?

A knocking-undercut anchor is set by striking the setting tool, which expands the anchor sleeve into the undercut. A screw-in undercut anchor is threaded into the hole and expands by turning. Knocking anchors are faster to install and are often used for repetitive fixings in stone cladding.

Can you provide anchors for 30 mm thick granite panels?

Yes. We supply undercut anchors specifically designed for thin stone slabs, typically 20–40 mm thick. We adjust the anchor length and expansion sleeve to suit the panel thickness and the required load capacity.

Do you offer stainless steel anchors for coastal projects?

Yes, we manufacture anchors in A4 (316) stainless steel for high-corrosion environments. We also provide passivation and surface testing to ensure long-term durability.

What is the minimum order quantity for custom anchors?

For standard sizes, we can accommodate small trial orders. For custom-engineered anchors, we typically require a minimum quantity to cover tooling and setup, but we will discuss this based on your project volume.

How do you ensure the anchors meet international standards?

Our production follows ISO 9001 quality management practices. We perform in-house testing and can provide certificates from third-party labs such as SGS, BV, or TUV upon request.