Riveting in Sheet Metal Fabrication(anodized finish Aries)
- source:GAENOR CNC Machining
What is a Rivet?
A rivet is a mechanical fastener that consists of two main parts - the rivet body and mandrel. The rivet body is a head on one end and a shank on the other. The shank is inserted through pre-drilled holes in the materials being joined. The mandrel fills the hollow center of the rivet body and helps create the characteristic “shop head” when installed using a riveting hammer, rivet gun, or other riveting tool. Rivets work by permanently deforming the shank, which expands to lock the rivet in place. This creates a solid connection point that can’t be easily removed like a bolted or screwed joint.
Benefits of Riveting Sheet Metal
There are several advantages that make riveting a popular choice for joining sheet metal in fabrication:
- Strong and permanent - Rivets form a solid mechanical connection that won’t come loose over time like fasteners that can unscrew or untighten. The deformed shank tightly locks materials together.
- Simple installation - Riveting is generally quick and straightforward, only requiring access to one side of a joint to install. Minimal tools and training is needed.
- Versatile - Rivets can join a wide range of materials and material thicknesses. The same rivet can often be used in different applications.
- Smoother surface - Unlike screw or bolt heads, installed rivets have a relatively low profile that won’t interfere with material handling or other operations.
- Cost effective - Rivets themselves are inexpensive. Installation also requires minimal labor and tooling.
- Aid alignment - The close tolerances of rivet holes can help align sheet metal parts precisely before permanent assembly.
Types of Rivets for Sheet Metal
There are several types of rivets commonly used for sheet metal fabrication:
- Solid/blind rivets - These have a rivet body and mandrel as one solid piece. They are installed using a rivet gun or riveting tool from one side, making them ideal for assemblies where access is only available to one part surface. Blind rivets are available with flat or countersunk heads.
- Pull type blind rivets - These also can be installed from one side, but have a mandrel that is pulled off after setting the rivet. The mandrel stem is discarded afterwards. Pull types includeclosed end, open end, and multi-grip styles.
- Self-plugging/piercing rivets - Designed to punch through and join lighter gauge sheet metals without pre-drilling. Often used for auto body panels, appliance housings, electronics, and similar manufacturing.
- Structural rivets - Used for assembling structural metal products like truck frames, building beams, and bridges. They have high shear and tensile strength. Structural rivet styles include round head, countersunk head, and universal head.
- Tubular rivets - These have a hollow tubular body lacking a mandrel. Installed using two-sided dies to flare each end of the rivet body. Used for permanent sheet metal connections exposed to vibration.
- Drive rivets - Hardened steel rivets that are installed using hammer blows rather than pull force. Drive rivet styles include round head, countersunk, flat head, and modified flush.
Best Practices for Riveting Sheet Metal
To achieve safe, strong, and professional results riveting sheet metal, follow these guidelines:
- Select the proper rivet type and size - Match the rivet strength, head style, and grip range to your specific application. Consider factors like materials, thickness, and accessibility.
- Ensure parts are properly aligned - Any misalignment can compromise rivet strength or cause distortion. Clamp pieces with C-clamps, vise grips, or temporary fasteners to keep aligned while riveting.
- Drill accurate and clean holes - Use sharp drill bits suited for metal and the hole size required. Deburr holes so rivets can insert smoothly.
- Follow recommended hole spacing - Space rivets too close and the material can distort. Too far apart weakens the connection. Refer to rivet manufacturer specs.
- Use quality riveting tools - Well maintained and calibrated rivet guns, hammers, and other specialty tools are essential for proper rivet setting. Don’t use worn or damaged tools.
- Set rivets completely and consistently - Partial setting leaves a weak connection. Develop consistent technique and inspect set rivets.
- Use backup support - Back up the material on the blind side with steel bars, bucking bars, or heavy blocks to minimize distortion.
- Stagger rows of rivets - Offset rivets in adjacent rows so they don’t weaken the material in straight lines.
- Apply sealant when needed - Sealant/adhesive between riveted joints prevents leakage and improves corrosion resistance.
Following basic riveting principles and techniques leads to professional results assembling sheet metal components. With an understanding of the rivet options and how to properly install them, this simple yet versatile fastener can address a wide range of sheet metal fabrication needs. CNC Milling CNC Machining