Rivets in Sheet Metal Fabrication(deburr Heloise)

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Rivets are a popular and versatile mechanical fastener used in many sheet metal applications. They provide a strong and permanent method for joining two or more sheets of metal together. Here is an overview of rivets and how they are used in sheet metal fabrication.
What is a Rivet?
A rivet is a mechanical fastener consisting of two main parts - a smooth cylindrical shaft and a head. The shaft is inserted into holes drilled through the materials being joined. The excess length of the shaft extends out the other side where the head is formed to lock the rivet in place. This creates a permanent joint.
Rivets come in many sizes, shapes and materials. Some common types include:
- Solid/Blind Rivets - The head is formed on one end of the pre-assembled rivet. As it is set, the head pulls the shaft tail, expanding the rivet body to form a second head.
- Drive Rivets - Has no pre-formed head. They require access to both sides of the workpieces during installation. As the tail is upset, it expands the body.
- Split Rivets - The shaft has a pre-formed head on one end and splits along its length. As it is set, the splits flare outwards to lock in place.
- Structural Rivets - Used in high-strength structural applications. Made from aluminum, steel, nickel and other alloys.
- Self-Pierce Rivets - Designed to pierce and join sheet metals without pre-drilled holes.
Benefits of Rivets in Sheet Metal
Rivets offer unique benefits that make them a versatile fastening method for many sheet metal applications:
- Permanent Joint - When properly set, the mechanical locking action of the deformed rivet shaft creates a permanent joint that will not loosen over time.
- Vibration Resistant - Rivet joints can withstand high levels of vibration and shock loading without coming loose. This makes them well-suited for equipment and machinery.
- Easy to Install - Setting most rivets is a simple operation using only simple hand tools. Minimal training or expertise is required.
- Variety of Materials - Rivets come in a wide range of materials including aluminum, steel, stainless steel, copper, and more to suit the application.
- Accommodates Varied Thicknesses - Many rivet styles can join disparate thickness combinations from thin sheet metal to thick plate.
- Leakproof Joint - When set properly, the mechanical deformation of the rivet shaft creates a tight joint that will not allow leakage of gasses or liquids.
- Corrosion Resistant Options - Stainless steel and aluminum rivets provide good corrosion resistance while still offering high strength.
Common Riveting Applications
Thanks to their versatility, rivets are very commonly used in sheet metal fabrication across many industries including:
Aerospace - Rivets are extensively used in aircraft assembly to join the aluminum skin to the internal structure. The vibration resistance and leak proofing of rivets make them ideally suited for these applications.
Automotive - Self-piercing rivets are often used for auto body panels and attachments where a waterproof and permanent joint is needed.
Appliances - The thin metal housings of appliances often utilize rivets at the seams and to attach components. Their permanent nature prevents loosening from vibration.
Electronics - Small aluminum and steel rivets provide durable fastening inside electronic devices and cabinets where screws may loosen over time.
HVAC Ductwork - Rivets are commonly used to assemble sheet metal duct sections into ductwork systems. Their permanence prevents leaks at joints.
Plumbing/Roofing - Rivets securely join sheet metal used in roofing, flashing, downspouts and other building applications where water-tightness is crucial.
Lighting - Rivets fasten sheet metal light fixture housings. Riveted seams maintain electrical grounding between fixture components.
Guide to Riveting Sheet Metal
When riveting sheet metal, following proper procedures is key to achieving secure, leakproof, and permanent joints:
- Hole Size - For most rivets, holes should be 1/16" larger than the shaft diameter. This allows the rivet to be inserted through the sheets but still deform and fill the holes when set.
- Hole Spacing - Rivets should be spaced between 2 to 4 times the rivet diameter apart. Closer spacing can split the surrounding material.
- Hole Alignment - Holes in all stacked sheets must be well aligned to allow straight rivet insertion. Offset holes will produce a weak joint.
- Rivet Length - The rivet length should be slightly greater than the total thickness of the material being joined. Approximately 1/16" grip length is ideal.
- Setting Force - Apply sufficient force when bucking or upsetting the tail to deform the rivet body and fill the holes. This expands the rivet to grip the sheets.
- Bucking Bar/Set - Use an appropriate bucking bar or rivet set that matches the rivet head shape to avoid damaging it when setting.
- Rivet Fill - A properly set rivet will completely fill the hole and be flush with the material surface. Minimal gap between the head and material indicates good fill.
- Workpiece Support - Support the material being riveted with a bucking bar or heavy backing plate during setting to prevent bending or warping the metal.
Properly drilling holes, selecting and setting rivets will result in long-lasting sheet metal joints. Rivets form secure connections while still allowing some flexibility to account for thermal expansion and contraction. Their versatility ensures rivets will continue to be a trusted fastening method for all types of sheet metal work. CNC Milling