Black Double Straight Knurl Flanged Cylindrical Insert Nut

Core Features

Double Straight Knurl External Surface – Two straight knurl sections are formed on the cylindrical body, providing increased surface contact with the host material compared to single knurl configurations. The dual knurled sections create mechanical retention that resists axial pull-out and rotational movement when pressed into the host material.

Integrated Flange – A circular flange is formed at one end of the cylindrical body, serving as a positive stop to control insertion depth during installation. The flange provides a load-bearing surface that distributes clamping force across the workpiece.

Internal Threaded Bore – The central bore contains pre-formed internal threads that accept standard bolts or screws, enabling component attachment after the insert nut is installed into the base material.

Black Finish – The black surface treatment provides a uniform appearance with defined corrosion resistance and wear protection properties.

Product Characteristics

The fastener is manufactured with a cylindrical body and two straight knurled sections on the external surface. The straight knurl pattern consists of parallel ridges formed along the length of each knurled section. The outer diameter is dimensioned to provide an interference fit with standard hole sizes in the host material. The double knurl configuration increases the total retention area compared to single knurl designs.

The integral flange extends outward from the body at the insertion face. The flange underface provides a bearing surface that contacts the workpiece when the insert is fully seated. The flange thickness and diameter are dimensioned to provide load distribution and resist pull-through forces.

The internal thread is produced with thread dimensions and tolerances following standard metric or imperial thread profiles. Material composition is controlled to meet specified strength requirements. Carbon steel grades are available for general applications, with material selection affecting press-fit characteristics and retention performance. The black finish is applied through a coating or conversion process, providing a consistent surface appearance with defined thickness and corrosion resistance properties.

Application Scenarios

Wood and Composite Assembly – Used in furniture manufacturing, cabinetry, and woodworking where insert nuts are pressed into pre-drilled holes to provide threaded attachment points for components. The double knurl provides increased retention in wood materials and the flange prevents over-insertion.

Plastic Enclosure and Molded Parts – Applied in electronic enclosures, plastic housings, and molded components where insert nuts provide threaded receptacles in plastic materials. The double straight knurl increases the retention surface and prevents rotation.

Sheet Metal Applications – Used where a threaded hole is required in sheet metal that is too thin to tap, and where press-fit installation provides a permanent threaded insert.

Electronics and Precision Equipment – Employed in electronic enclosures and instrument casings where inserts are required for board mounting and mechanical attachments. The flange provides a positive stop for consistent installation depth.

Customization Options

Specifications and configurations can be adjusted based on application requirements. Outer diameter, flange diameter, length, and thread size are customizable according to application geometry. Material grades include carbon steel for general applications, brass for decorative and corrosion-resistant requirements, and stainless steel for enhanced corrosion resistance. Surface treatments include black oxide, zinc plating, nickel plating, and phosphate coating.

Frequently Asked Questions

Q: What is the purpose of the double straight knurl configuration?
A: The double straight knurl provides increased retention surface area compared to single knurl designs. The dual knurled sections create multiple interference zones with the host material, enhancing resistance to axial pull-out and rotational forces.

Q: What is the purpose of the flange on this insert nut?
A: The flange serves as a positive stop during installation, preventing the insert from being pressed too deeply into the hole. It also provides a bearing surface that distributes clamping force across the workpiece and resists pull-through forces under load.

Q: What materials are compatible with these insert nuts?
A: Double straight knurl insert nuts are compatible with wood, plastic, and certain metal applications where the insert is pressed into a pre-drilled hole. The host material should be softer than the insert nut material to allow the knurl ridges to bite into the surrounding material.

Q: Can these nuts be removed after installation?
A: The insert nut is intended for permanent installation. Once pressed into the host material, removal typically damages the surrounding material or the nut itself. For applications requiring removal or replacement, alternative fastening methods should be considered.

Q: What is the recommended installation method?
A: The insert nut is pressed into the hole using a press or hammer. Standard drills or drill presses may be used in small production runs, while automatic feeding systems are recommended for large volume production. The flange provides a positive stop for consistent insertion depth.

Q: What is the difference between this and single knurl insert nuts?
A: The double knurl configuration provides two separate knurled sections along the length of the cylindrical body, increasing the total surface area available for retention compared to single knurl designs.

Installation Considerations

The hole diameter should be dimensioned to provide the specified interference fit with the knurled body sections. Hole tolerance control is important for achieving consistent insertion force and retention performance. During installation, the insert nut should be aligned with the hole and pressed vertically to avoid angular misalignment that may damage the insert or host material.

The flange ensures consistent insertion depth when the insert is fully seated against the workpiece surface. The undercut at the flange-base junction allows the insert to sit flush with the host material. When installing into plastic materials, consideration should be given to material flow and potential stress cracking. For wood applications, pre-drilling to the recommended diameter should be performed without causing splitting or excessive material displacement.