Construcciones Yamaro: Hobson Engineering calls time on nonconforming allthread
Allthread may seem unremarkable, but when quality fails, the consequences are anything but. Hobson Engineering is urging the industry to take a closer look.
Allthread – also known as threaded rod or stud – is one of the most commonly used fasteners in construction, infrastructure and manufacturing. Its simplicity belies its importance: securing structural elements and supporting everything from columns to hanger systems.
But its widespread use comes with a catch. When allthread doesn’t meet specifications, the risks multiply. Structural failure, costly rework and safety incidents can follow. And yet, the issue of nonconforming allthread often flies under the radar. For Hobson Engineering, that’s not good enough.
The company has spent decades advocating for better awareness of fastener quality, from site supervisors to specifiers. Now, it is drawing attention to one of the most overlooked components on site.
Anchoring confidence
“Allthread is the most common anchor used for hold down bolts,” says Alex Sharp, senior engineer at Hobson Engineering. “A hold down bolt anchors structural elements – such as steel columns, timber posts or machinery – firmly to a concrete base. It resists uplift, shear and tension forces, helping to keep the structure in place.”
It’s also a backbone of support systems. Allthread is used to suspend strut frameworks that brace, support or stabilise components in construction, mechanical or electrical installations.
“These systems are especially common in building services like plumbing, HVAC and electrical work,” adds Sharp. “People often don’t think about allthread until it fails. And by that point, the cost and safety consequences can be severe.”
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Standards and steel
The reliability of allthread begins with standardisation. From Joseph Whitworth’s 18th-century thread forms to today’s metric and unified systems, thread profiles have long been governed by geometry. Most fasteners use a 60-degree thread angle to ensure compatibility and strength.
“Hobson Engineering carries a diverse range, with 14 different thread forms stocked, including Metric, Unified, Whitworth, ACME and BA,” says Sharp.
But adhering to standards is only part of the equation. Material quality and thread formation are just as critical, and just as vulnerable to shortcuts.
One common issue begins with the bar stock itself. Some manufacturers reduce the rolling diameter to save on material, creating an undersized thread that appears compliant but won’t achieve the expected strength. Others manipulate the thread angle – narrowing it to 30 degrees or less – allowing thinner stock to mimic a standard profile.
“Even small changes like this can significantly compromise strength,” says Sharp. “It might pass a visual check, but under load, the difference becomes very real.”
When standards slip
When threads are rolled – the typical method for mass production – steel is not cut away but extruded to shape. This is efficient and economical, but the input diameter is critical. Too small, and the material is overstressed, particularly at the thread roots. This can introduce brittleness and reduce fatigue resistance. By reducing the input diameter, manufacturers can save around 24 per cent of material. The consequences? Tensile strength losses of up to 34 per cent. Cracks under load. Failures in service.
“Allthread used to hold down a roofing system in a cyclonic area, for example, needs to achieve its stated strength,” says Sharp. “If not, the entire roof could detach during a cyclone event. That line of thinking applies to every use – from bracing pipework to securing plant.”
It’s a sobering reminder that not all fasteners are created equal. And yet, in a price-driven market, cost-saving measures continue to threaten quality standards.
A legacy of control
Hobson Engineering’s focus on quality dates back nearly a century. Company founder Ron Hobson was quick to spot the potential of threaded rod after a contact returned from the United States post-WWII. The company began producing allthread in-house, drawing, rolling and testing under one roof.
As local galvanising and plating declined, the company pivoted, importing selectively and expanding its own testing capacity. Today, Hobson maintains in-house testing capabilities and routine quality inspections of incoming batches in its NATA-accredited lab. For high-strength products, verification test reports are approved by the company’s quality team before stock is released for sale.
“The testing process depends on the thread form and material, but all follow similar principles,” says Sharp. “Thread inspection, proof or tensile tests, hardness checks, and for high-tensile grades, decarburisation testing.”
Hobson Engineering routinely tests heat-treated and high tensile rods, with random sampling for Class 4.6. Test reports are ILAC‑accredited and available to specifiers online for transparency. Each branch also carries thread inspection tools for random checks – a last line of defence before product reaches site.
Drawing the line
Despite these efforts, Sharp says the issue of nonconforming fasteners is still underappreciated, especially in allthread.
“Checking allthread is impractical for end users and is unlikely to catch all issues,” he says. “That’s why engineers, specifiers and procurement teams need to treat allthread as a safety-critical item. Specify trusted suppliers who can provide quality assurance documentation, including test certification.”
Sharp’s position is firm: No assurance in source means no certainty in strength.
“Nonconforming allthread won’t perform as intended,” he says. “As with any engineered system, meeting minimum requirements for strength, ductility and durability is essential to avoid failure. Fixing issues caused by substandard fasteners can be costly.”
For Hobson Engineering, quality is a responsibility it takes seriously. In an industry built on trust, the company continues to advocate for standards that hold fast.
For technical guidance or to request ILAC reports, contact the Hobson Engineering team at engineering@hobson.com.au
The post Hobson Engineering calls time on nonconforming allthread appeared first on Inside Construction.
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