Inside the Tube: The Secret Technique Turning Ordinary Steel into Super-Strong Structures

In the realm of metal fabrication, the simplest challenges often demand the most ingenious solutions. When Jer Schmidt faced the daunting task of securing sturdy bolts inside long, narrow steel tubes - where traditional methods fell flat - he didn’t reach for high-tech gadgets or expensive specialty tools. Instead, he reimagined the humble nut and bolt, devising a method that’s as accessible as it is effective. His inventive approach is now sparking conversations among makers and engineers alike, shining a light on the overlooked art of making strong connections in the trickiest of places.

Fast Facts

• Standard thread tapping isn’t strong enough for thin-walled steel tubing.
• Jer Schmidt developed a method to weld nuts inside inaccessible metal tubes using plug welds.
• The technique only requires basic hardware store parts and simple homemade tools.
• This method is ideal for projects requiring multiple strong threaded holes in long or closed tubes.
• Alternatives like rivnuts exist, but Schmidt’s approach avoids specialty parts.

Cracking the Case: How to Weld a Nut Where No Hand Can Reach

Schmidt’s dilemma was a classic one: how to create reliable, load-bearing threaded holes inside a slender steel tube, when the walls are too thin for conventional threading and the inside is out of reach. The common workaround - using a rivnut - wasn’t an option for his project, which demanded a more robust, scalable solution without resorting to specialist supplies.

The breakthrough came with a deceptively simple process. First, Schmidt drilled a central hole for the bolt, then two smaller holes on either side. A standard nut is inserted into the tube and positioned behind the main hole using a straightforward homemade tool - just a stick of scrap wood cut to size. Holding the nut in place, he performed plug welds through the small side holes, fusing the nut securely to the inner wall of the tube. After a quick grind to smooth the exterior, the result is a hidden, ultra-strong threaded anchor, all accomplished without ever touching the inside surface directly.

Not only does this technique sidestep the need for expensive hardware, it also empowers hobbyists and professionals to create durable joints in places previously considered inaccessible. The method’s beauty lies in its adaptability: no special equipment, no proprietary fasteners - just off-the-shelf nuts, bolts, and a welder. Schmidt’s solution is a testament to the power of hands-on ingenuity, and it’s quickly gaining traction in workshops where creativity meets constraint.

Looking Forward

As more makers discover this method, it’s likely to become a staple in the fabrication toolkit - especially for those working on custom frames, robotics, or any project where strength and stealth are required inside a metal tube. Schmidt’s approach reminds us that sometimes, the best hacks are born not of high technology, but of a willingness to rethink the basics. In the world of metalwork, even the most hidden connections can hold the greatest strength.

WIKICROOK

• Plug Weld: Plug welding joins two metal surfaces by filling a hole with molten metal, creating a strong, durable bond without needing access to both sides.
• Threaded Hole: A threaded hole is an opening with internal threads, designed to accept a screw or bolt for secure fastening in hardware assemblies.
• Rivnut: A rivnut is a fastener combining a rivet and a threaded insert, enabling bolts to be used in thin or soft materials.
• Square Steel Tubing: Square steel tubing is a hollow, square-shaped steel section used in construction and fabrication for its strength, versatility, and ease of welding.
• Grinding: Grinding in cybersecurity means repeatedly attempting to breach systems, often by systematically testing passwords or vulnerabilities to gain unauthorized access.