Riveting in Sheet Metal Fabrication(rivits Osborn)

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Rivets have been used since ancient times to join pieces of metal together in a strong and permanent way. In modern sheet metal fabrication, riveting is still one of the most common and effective techniques for assembling components.
What is a Rivet?
A rivet is a short cylindrical rod with a head on one end. The rivet is inserted through holes drilled in the parts to be joined and the protruding end is then hammered and compressed, forming a second head. This process is called riveting. The force of compressing the rivet shank creates a permanent joint by cold working and upsetting the material. This avoids the need for welding or any other heat-based joining technique.
There are two main types of rivets used in sheet metal fabrication - solid rivets and blind rivets. Solid rivets are one-piece and require access to both sides of the material. Blind rivets can be installed from one side by using a specialized rivet gun. The mandrel stem of the rivet is pulled through the rivet body, upsetting the rivet and forming the second head.
Advantages of Riveting
Compared to other fastening methods, riveting in sheet metal fabrication offers several benefits:
- Permanent Joining - Once installed, solid rivet joints are permanent and do not come loose over time. The upset rivet shank firmly joins the materials.
- Strength - Properly installed rivets create very strong joints, even in thinner gauge sheet metals. Riveted panels can handle significant loads and forces.
- Vibration Resistance - Riveted joints are resistant to shock, vibration, and fatigue stresses better than many other fasteners.
- No Heat or Sparks - The cold working process avoids heat input which could warp or damage the surrounding material. No sparks are created.
- Assembly Speed - Experienced riveters can quickly install many rivets to assemble components. Minimal equipment is required.
- Corrosion Resistance - The rivets can be made of corrosion resistant materials or coatings. Stainless steel and aluminum rivets are common.
- Lightweight - Rivets add very little weight versus welding or using bulkier fasteners. This aids the aircraft and transportation industries.
These advantages make riveting ideal for all types of sheet metal enclosures, ducts, panels, aviation and aerospace applications, machinery guards, electronic chassis, and any place where permanent, strong, lightweight joints are needed.
Rivet Materials and Styles
The most common materials for rivets include:
- Aluminum - Offers good strength at low cost but has lower shear strength than steel. Used for aluminum assemblies.
- Steel - Very high strength but more susceptible to corrosion. Often zinc plated. Used for high strength applications.
- Stainless Steel - Greatest corrosion resistance. Highest cost, but excellent for harsh environments.
- Monel - Corrosion resistant nickel alloy for marine and chemical applications.
- Copper - Good electrical and thermal conductivity. Easily worked when hot. Used in electronics.
- Plastic/Nylon - Insulating and lightweight. Used in electrical and interior applications.
The head styles can be round, countersunk, or flat head. Different head types suit different assembly needs.
Riveting Process Basics
Riveting in sheet metal requires a few basic steps:
1. Cutting or punching the rivet holes - Holes are cut or punched to match the rivet diameter. Deburring is needed to ensure fit.
2. Selecting the rivet length - Rivet length must exceed total material thickness but not be too long.
3. Inserting the rivet - Solid rivets are inserted through the aligned holes. Blind rivets are inserted into one side.
4. Setting the rivet - Solid rivets are bucked off using a hammer and bucking bar on the backside while the rivet stem is upset. Blind rivets are set using the rivet gun.
5. Inspecting the joint - Ensure the rivet has formed a solid head and clinched tight to materials. Check for any cracks.
Proper hole size and rivet length, solid pressure during setting, and inspection of the set rivet are critical to create a lasting quality joint. Workers must be trained on all steps.
Riveting Tools
Basic riveting requires only simple tools - rivet sets, hammers, bucking bars, and inspection gauges. But power tools can increase productivity and quality. Common power tools include:
- Pneumatic rivet guns - Fast pulling of blind rivets. Easy one-hand operation.
- Squeeze riveters - Hydraulic jaws compress solid rivets to form the second head.
- Impact riveters - Power hammering for solid rivets in high volume production.
- Orbital riveters - Spin/vibration system to quickly upset rivets. Minimal operator effort.
Automated tooling can install hundreds of rivets per hour consistently. This is ideal for mass production. But manual tools still play an important role in lower volume fabrication.
Riveting Tips
Follow these proven tips for successful riveting:
- Use the recommended hole size - Undersized holes can crack the material when set. Oversized holes reduce strength.
- Select a rivet length 1.5x the material thickness - Too short won't clinch properly, too long can split the rivet.
- Ensure rivet gun pressure is set correctly - Improper pressure leads to loose or damaged rivets.
- Use a bucking bar on the backside - Prevents distortion of thin materials during setting.
- Set rivets in the center of the hole - Offset placement will weaken the joint.
- Use washers for soft materials - Distributes force and prevents tearing around the rivet.
- Set specialty rivets following instructions - Different types have specific setting requirements.
- Conduct test sets first - Confirm hole size, gun pressure, and technique before production.
- Inspect each rivet after installation - Make certain both heads are formed and tight.
Proper training and procedure is vital to creating riveted joints that will withstand years of service. But when done correctly, riveting remains an economical, reliable, and robust fastening solution for all sheet metal assembly needs. CNC Milling