Detailed Technical Guide

A brass barbed expansion insert is a threaded metal component fitted into a prepared hole in a host material. It provides a reusable threaded connection where directly cutting threads into the host material may not be practical.

The exact design on your linked product page determines how it is installed: some inserts use external barbs to grip the surrounding material, while expansion-style designs use a screw or other mechanism to expand the insert and improve retention.

Product construction and design

A. Internal thread

Accepts a matching metric or imperial screw. Thread size, pitch, engagement length and tolerance determine compatibility and load capacity.

B. External barbs or serrations

Bite into or engage the host material to resist axial pull-out and rotation. Their geometry must match the intended installation method and material.

C. Body, shoulder and lead-in

The body provides thread engagement. A shoulder, if present, controls insertion depth; a chamfer or tapered lead-in helps guide the insert into the prepared hole.

Typical materials and manufacturing specifications

Important: These are general engineering options, not verified specifications for the product at your link. The correct brass grade and geometry should be confirmed with the manufacturer.

How the insert works

4. Manufacturing process

For a brass insert manufactured from round bar stock, a typical production sequence is:

For higher production volumes, multi-spindle automatic lathes can improve throughput. The most economical process depends on the insert’s shape, tolerances, annual volume and whether the barbs can be machined in the same setup.

Quality-control checks

The following characteristics are especially important:

• Thread gauge: Verify the internal thread using the appropriate GO/NO-GO gauge.

• Outside diameter: Confirm the maximum and minimum dimensions of the barbed section.

• Overall length: Ensure the insert sits at the intended depth.

• Concentricity: Check alignment between the internal thread and external body.

• Pull-out resistance: Test retention in the actual host material.

• Torque resistance: Check whether the insert rotates when the screw is tightened.

• Burrs and cracks: Inspect thread entrances and barb edges.

• Material verification: Confirm brass alloy requirements and any applicable restrictions on lead content.

What determines the manufacturing cost?

The main cost factors are brass consumption, cycle time, tooling, thread size, machining complexity, finishing, inspection and order quantity.

For a reliable estimate, the manufacturer’s drawing should specify the thread, dimensions, material grade, tolerances and surface finish. A photograph alone is not sufficient to calculate an accurate production cost.