What Are Fasteners? Types, Uses, and how to choose the Right One 

If you’ve ever started a construction, manufacturing, or DIY project and found yourself staring at a drawer full of bolts, nuts, brackets, and connectors wondering which one actually does what — you’re not alone. Fasteners are the components that hold structures together, and choosing the wrong one for your application is one of the most common and costly mistakes in any build. 

This guide answers the questions people search for most: what are fasteners, what types exist, how nut and bolt fasteners actually work, and how the fastener category goes far beyond what most people picture when they hear the word. 

What Are Fasteners? 

Fasteners are hardware components designed to mechanically join or affix two or more objects together. They create connections that range from fully permanent — like a rivet — to fully adjustable and reusable, like the T-nut and bolt systems used in modular aluminium extrusion framing. 

The term covers an enormous range of products. In the context of modular construction and industrial building systems, fasteners include not just traditional nut and bolt fasteners but also internal connectors, anchor assemblies, bracket systems, pivot joints, and variable angle components — all of which serve distinct structural purposes depending on how the joint needs to behave. 

When people ask “what are fasteners?” they’re often starting from a general hardware context. But in modular framing, the answer is more specific: fasteners are the engineered connection components that allow aluminium profiles to be joined cleanly, precisely, and reconfigurably — without welding, without drilling into the profile, and in most cases without special tools. 

Key nut and bolt components in the 8020 range include: 

T-Nuts — the critical interface between the bolt and the extrusion channel. Available in roll-in (slide-in anywhere along the slot) and drop-in (inserted from the end) configurations, and in both M6 and M8 thread sizes to match different profile series. 

T-Slot Studs — stud fasteners that sit within the T-slot channel and accept nuts from the outside, used where a bolt-from-one-side configuration isn’t possible. 

Stainless Steel Bolts — for applications where corrosion resistance matters: outdoor structures, food processing environments, and marine-adjacent installations. 

Steel Bolts — the standard choice for the majority of indoor industrial and commercial framing applications.

Types of Fasteners in Modular Extrusion Systems 

The fastener category in modular framing extends well beyond nut and bolt combinations. The connection type you need depends on where in the frame the joint sits, what load it needs to carry, and whether it needs to be adjustable or fixed. 

Internal Fasteners 

Internal fasteners sit inside the aluminium profile and create connections that are largely hidden from view. They’re preferred where a clean external finish is required — machinery enclosures, retail displays, workstations, and any application where visible hardware on the surface isn’t desirable. 

The internal fastener subcategories cover distinct joint types: 

Anchor fasteners — used to join two profiles end-to-face. The assembly inserts into an access hole drilled in one profile and anchors against the internal wall of the cross profile, drawing the connection tight. A common choice for frame corners and structural joints where internal engagement is preferred over external brackets. 

End fasteners — connect profiles end-to-end or end-to-face using a threaded engagement into the end of the profile. Standard end fasteners are available in M6 and M8 configurations to suit 25 Series and 30/40 Series profiles respectively. 

Butt fasteners — similar to end fasteners but designed for perpendicular connections where the cross-profile doesn’t have a machined access hole, using the T-slot channel of the receiving profile to anchor. 

Bolted connectors — high-load internal connections for joints that need to carry more significant shear or tension forces than a standard anchor or end fastener. 

Milling connectors and inside corner connectors complete the range for right-angle internal connections. 

External Fasteners and Brackets 

External hardware sits on the outside of the frame and provides visible, load-bearing connections. This is the right choice when fast assembly, easy repositioning, or higher load capacity is the priority over a clean finish. 

The external range includes: 

Inside corner brackets — L-shaped brackets that span the inside corner of two perpendicular profiles. Available across all series (25, 30, 40) with hole count and profile varying by load requirement. The 2-hole lite bracket is suited to light-duty connections; the 8-hole inside corner bracket is appropriate for heavier structural joints. 

45-degree supports — triangular bracing components that reinforce frame corners and prevent racking. Essential in taller frames and overhead structures where lateral rigidity matters. 

Joining plates and gussets — flat or L-profile plates that span the outside of a joint for added stiffness or to join profiles in a flat (co-planar) configuration. 

Variable Angle Connections 

Not every joint in a frame is 90 degrees. The variable angle connection range handles joints from 0 to 90 degrees and beyond, including: 

Pivot joints — allow two profiles to be connected at a fixed angle during assembly, with the angle set and locked before tightening. Available across 10/25 Series, 30 Series, 40 Series, and 45 Series profiles. 

Adjustable clamps — allow fully continuous angular adjustment, useful in ergonomic workstation arms, display frames, and machinery guarding where the angle needs to remain adjustable after assembly. 

Structural pivot assemblies — complete pivot kits for 25 and 40 Series profiles, available in 0-degree, 90-degree, and universal configurations with straight or L-arm variants. 

How to Choose the Right Fastener for Your Application 

The right fastener depends on three things: the profile series you’re using, the load the joint needs to carry, and whether appearance matters. 

As a general starting point: 

For a clean, professional finish where the frame will be visible — use internal fasteners (anchor, end, or bolted connectors). They require an access hole in the cross-profile but result in a joint with no external hardware. 

For fast assembly, easy reconfigurability, or higher structural loads — use external brackets (inside corner brackets, gussets). They’re quicker to install and can be repositioned without machining. 

For standard nut and bolt fasteners that engage with the T-slot — start with M6 T-nuts and M8 x 12mm button head socket cap screws for 25 Series profiles, and M8 T-nuts with M8 x 16mm bolts for 30 and 40 Series. 

For joints at non-standard angles — use the variable angle or pivot joint range.

If your project is in Sydney and you’re unsure which fastener series matches your profile, 8020’s technical team at Seven Hills can assist with component selection and provide instant quotes for both standard and custom requirements. 

Why Fastener Selection Matters More Than Most People Realise 

In modular framing, the fastener is often where projects go wrong. Using the wrong thread size, the wrong T-nut type, or the wrong bracket for the load means joints that loosen over time, frames that rack under lateral load, or assembly that simply doesn’t work as intended. 

The 80/20 fastener range is engineered to work together with the corresponding aluminium profiles — meaning the thread engagements, hole patterns, and T-slot dimensions are matched across the system. This matters whether you’re building a small workbench in a Sydney workshop or specifying a multi-cell automation enclosure for an industrial facility. 

With 552 fastener products across internal, external, hardware, and variable angle categories, 8020 Australia stocks the components for everything from a basic two-profile butt joint to a fully articulated multi-axis pivot assembly.