flow drilling

Threading for
Thin-Walled Tube Applications

Flow drilling and tapping provides a highly effective way to create strong, reliable threaded connections in thin-walled tube and hollow sections. By forming threads directly within the parent material, the process eliminates the need for welded bosses, threaded inserts and additional components. As a result, manufacturers can reduce costs, improve consistency and streamline assembly processes.

At Listertube, flow drilling forms part of our comprehensive range of tube processing services and is widely used across manufacturing and fabrication applications. We apply the process to steel, stainless steel, aluminium, copper and other alloys, helping customers create durable threaded connections where conventional threading methods are limited by material thickness. The result is a clean, strong fastening solution that delivers excellent performance and long-term reliability.

What is Flow Drilling?

Flow drilling is a thermal forming process that uses a high-speed rotating tool to generate heat through friction. As the tool penetrates the material, the displaced material is formed into an elongated bush around the hole.

The resulting bush typically provides up to 300% greater depth than the original wall thickness. This creates sufficient material for threaded connections that would otherwise be impossible or unreliable using the parent material alone.

Following the flow drilling process, threads can be tapped directly into the formed bush to create a strong and durable fixing point.

Material Compatibility

MILD STEEL

Well suited to flow drilling applications, providing strong threaded connections and excellent durability across a wide range of industrial uses.

STAINLESS STEEL

Flow drilling creates clean, reliable threaded bushes in stainless steel, making it ideal for demanding environments where corrosion resistance is essential.

ALUMINIUM

A lightweight material that responds well to flow drilling, allowing secure threaded connections without the need for additional inserts or fixings.

COPPER

Flow drilling can be used to create robust threaded features in copper components while maintaining material integrity and assembly efficiency.

COPPER Alloys

Suitable copper alloys can be flow drilled and tapped to produce strong, reliable threads for specialist fluid transfer and engineering applications.

Beyond threaded connections, many components also require additional manufacturing features to support assembly and functionality. Alongside flow drilling and tapping, we can incorporate slots, holes and cut features using our in-house tube cutting services. As a result, multiple processes can often be completed within a single manufacturing workflow, improving consistency, lead times and overall efficiency.

Advantages of
Flow Drilling

Benefits over conventional fastening and joining methods:
  • No access required to the rear of the workpiece for attaching a secondary nut
  • Creates a strong threaded connection within the parent material
  • Suitable for a wide range of thread diameters and material thicknesses
  • Eliminates the need for weld nuts, rivet nuts and inserts
  • Reduces component costs and assembly time
  • Creates a clean, reliable and repeatable fastening solution
  • Supports higher loading due to the homogeneous material structure

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