All About Aluminum Rivnuts: Types, Uses, Installation Methods

What Are Aluminum Rivnuts?

Aluminum rivnuts, sometimes called rivet nuts or nutserts, are tubular fasteners that combine the functionality of a rivet with the threaded hole of a nut. They consist of two pieces:

• The rivnut body: a flanged hollow cylinder that gets inserted into the material being fastened.
• An internal threaded insert: this sits inside the cylinder and provides machine screw threads for bolts.

During installation, the rivnut body gets deformed to create a blind head on the backside of the material. This secures it firmly in place while still allowing the bolt to engage with the internal threads.

Key Features and Benefits

Some of the notable features and advantages of aluminum rivnuts include:

• Lightweight - aluminum material reduces component weight.
• Corrosion resistant - protects against rust and degradation.
• Cost effective - more affordable than many alternate fasteners.
• Reusable - can be removed and replaced multiple times if needed.
• Vibration resistant - maintains tight clamp load despite vibration.

Types of Aluminum Rivnuts

There are a few main classifications of aluminum rivnuts based on their design and installation method:

Breakstem Rivnuts

These feature a breakable stem used to expand the rivnut body. Installation tools grip and pull on the stem, causing the body to flare out and create the blind head. The stem then snaps off flush with the fastened material.

No-Breakstem Rivnuts

Instead of a breakable stem, these rivnuts rely on the installation tool to directly flare the body. A hex head remains proud of the fastened material, allowing for easy removal. No-breakstem rivnuts are reusable.

Self-clinching Rivnuts

These rivets clinch into a prepierced hole during installation. Prongs on the tubular body dig into the hole’s walls securely locking it in place. Self-clinching rivnuts don't require access to the opposite surface.

Countersunk Head Rivnuts

Designed for flush surface mounting, these feature a low profile domed head that sits entirely within a countersunk hole. The rivnut body flares beneath the material's back surface to lock it in place.

Common Uses of Aluminum Rivnuts

Thanks to their secure fastening ability combined with light weight, aluminum rivnuts are extremely versatile. Some of their most popular applications include:

Automotive Manufacturing

Rivnuts securely fasten metal panels and enclosures across vehicle bodies and interiors. Their vibration resistance prevents loosening.

Appliances and Electronics

Aluminum rivnuts help assemble appliances, computers, machinery, and more. They withstand repeated assembly and disassembly for servicing.

Aerospace and Aviation

Extremely lightweight aluminum rivnuts meet the stringent demands of aircraft manufacturing. Rivnuts also better handle fuselage vibration versus screws.

HVAC Ducting and Piping

Rivnuts offer reliable fastening of HVAC system panels and enclosure hardware. Their reusability aids periodic duct access and resealing.

Installation of Aluminum Rivnuts

Properly installing aluminum rivnuts requires a few key steps - particularly for pop rivets needing flaring. While specifics depend on rivnut types, the general process is:

Drilling Holes

Appropriately sized holes get drilled through the materials being joined at fastening points. Hole diameters should closely match rivnut body dimensions.

Inserting Rivnuts

Rivnuts insert into predrilled holes with their flange or prongs resting against the near material surface. Take care to orient any breakstem correctly.

Flaring Rivnut Body

The specialized installation tool grips and pulls the breakstem or rivnut head. This force flares out the body, clamping materials together while forming a blind head.

Breaking Stem

Continued pulling force snaps off any breakable stem flush with the materials once flaring completes. This leaves just the rivnut body and threaded insert.

Bolting

Finally, bolts can screw into the rivnut’s threaded insert to complete the fastened joint. Take care not to overtighten and strip the internal threads.

Rivnut Installation Tools

A variety of hand, pneumatic, hydraulic, and battery powered tools install aluminum rivnuts. Tool selection depends on factors like:

• Rivnut type and size
• Installation access and force requirements
• Fastening application and quantities
• Budget

Common aluminum rivnut installation tools include:

Hand Riveting Tools

Inexpensive manual tools consisting of handles and interchangeable nosepieces to flare different sized rivnuts. Best for occasional use given significant physical effort.

Pneumatic Rivnut Tools

Leverage air pressure to generate installation force. Different nosepieces still accommodate various rivnut sizes. Provide increased power with less operator effort.

Battery Rivnut Tools

Rechargeable electric models offer the highest portability with no air hoses. Lower weight reduces operator fatigue. Limited runtime between charges.

Hydro-pneumatic Rivnut Tools

Combine air pressure and hydraulic power to produce extreme installation forces. Capable of setting heavy duty or extra large rivnuts. Higher equipment cost.

Aluminum rivnuts deliver versatile and robust fastening performance across countless applications. Their lightweight material combined with high strength makes rivets the ideal choice over alternate mechanical fasteners like nuts, bolts, and screws for bonding thin sheets of metal.

FAQs

What materials can you install aluminum rivnuts in?

Aluminum rivnuts reliably fasten into sheet metals, plastic panels, fiberglass, wood composites, and other solid yet penetrable materials around 1/16" to 1/4" thick. Not recommended for brittle glass or stone.

Do aluminum rivnuts loosen over time?

Properly installed aluminum rivnuts maintain consistent clamping force even despite vibration or thermal cycling. Their blind head and flaring keeps the rivnut body firmly embedded within the host material.

What size rivnut hole should I drill?

As a general rule of thumb, drill holes 0.1 mm to 0.5 mm larger than the specified rivnut body diameter. Smaller holes risk cracking the surrounding material during flaring while larger holes reduce clamping force.

Can you remove and reuse aluminum rivnuts?

No-breakstem designs allow non-destructive rivnut removal using standard hex tools. This enables multiple rivnut insertions and extractions for servicing or modifications. Other types must get drilled out for replacement.