Riveting Sheet Metal - A Guide to Proper Technique(nylon vs delrin Bishop)

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Riveting is a crucial skill for anyone working with sheet metal. Properly installed rivets create strong, long-lasting connections between metal parts. However, poor riveting technique can lead to weak joins or damage to the metal itself. In this article, we'll cover everything you need to know about riveting sheet metal successfully.
What is a Rivet?
A rivet is a mechanical fastener used to join two or more pieces of material. Rivets consist of a cylindrical shaft and a head on one or both ends. The rivet is inserted into pre-drilled holes in the materials being joined. The rivet shaft is then deformed to create a second head, clamping the materials together.
Rivets for sheet metal typically have domed heads on both ends of the shaft. They are installed by squeezing the rivet between two bars or pressing the rivet against an anvil using a hammer or rivet gun. This deforms the rivet shaft, spreading it outward to form the second head.
Benefits of Riveting Sheet Metal
Rivets offer several advantages over other fastening methods for sheet metal:
- Strong, permanent joints - Properly installed rivets do not loosen or deteriorate over time. The deformed shaft provides a tight clamping force.
- Vibration resistance - Riveted joints can withstand vibration and shock better than fasteners like screws or bolts.
- No threading required - Riveting avoids the need to thread holes or fasteners. This simplifies installation.
- Works for overlapping or multi-layer joints - Rivets can clamp several layers of material together.
- Allows for material differences - Dissimilar metals can be riveted together. Rivets accommodate differences in thermal expansion.
- Quick installation - Automated riveting tools allow very rapid fastening. Hand riveting also tends to be faster than bolting or screwing.
Proper Rivet Selection
Choosing the right rivet design and material is critical for any application. Here are key factors to consider:
- Sheet thickness - Rivet length must be adjusted for the combined thickness of the materials being joined. The rivet shaft should be 1.5-2x the sheet thickness.
- Rivet diameter - Larger diameter rivets are stronger but may deform the sheet if too big for the hole size. Match rivet size to hole diameter.
- Material strength - Rivet material must be stronger than the sheet metal to allow proper deformation. Softer rivets will fail before deforming fully.
- Corrosion resistance - Select rivet material that is compatible with the sheet metal to avoid galvanic corrosion.
- Rivet head style - Countersunk, round head, or flush rivets are common choices depending on clearance needs.
Proper sheet metal prep is crucial for rivets to function as designed. Drilling precisely aligned, clean holes of the correct size allows rivets to slide in smoothly and grip effectively. Here are key steps for prep:
- Mark hole locations using a template or measurements. Transfer marks using an center punch.
- Drill perpendicular pilot holes slightly smaller than the rivet diameter. A stepped drill bit helps reduce burrs.
- Increase pilot hole size incrementally to reach the optimal diameter. Check rivet fit often to avoid oversizing.
- Deburr holes thoroughly after drilling using a deburring tool, file, or fine grit sandpaper. Rivets should slide through smoothly.
- Clean sheet surfaces and holes to remove metal chips, dirt, oil etc. These can interfere with rivet bonding and strength.
Riveting Technique
With suitable rivets and properly prepared holes, you can move on to installation:
- Insert the rivet into the holes, ensuring the manufactured head sits flush against one side of the sheet.
- Position riveting dies or bucking bars against the rivet tail. For hand riveting, a heavy hammer is required.
- Strike the rivet head or activate the riveting tool while applying pressure from the die side. This deforms the rivet shaft outward to form a second head.
- Continue striking until the rivet head forms completely and pulls the materials tightly together. The shaft will deform across its entire length.
- Check that the set rivet head is tightly clinched against the sheet without cracking or loosening. Tap the rivet to check for any movement.
- For large projects, work systematically across the sheet to avoid warping. Apply rivets to opposite corners first to pull the sheets into alignment.
- For hand hammering, use smooth, controlled strikes. Excessive force can damage the surrounding metal. Let the hammer weight do the work.
- Use a rivet spacing of at least 2x the rivet diameter between adjacent rivets. Rivets need sufficient material around them to clench properly.
Inspection and Troubleshooting
Always inspect your work thoroughly after riveting. Watch for these potential defects:
- Loose rivets - Rivet never deformed fully to clinch the sheets. Try re-striking with more force.
- Rivet cracking - Brittle or poor quality rivets can crack during installation. Replace with a rivet made of forged material.
- Sheet dimpling or distortion - Rivet is enlarged more on one side, distorting the metal. Use smooth hammer blows and quality rivets.
- Rivet rotation - Rivet head is misaligned due to rotation during installation. Hold it firmly in place when striking.
- Scratched or gouged metal - Hammering has damaged the surrounding material. Use less force or a rivet buffer tool.
Mastering proper riveting technique allows you to create incredibly strong sheet metal connections quickly and reliably. Follow the guidelines above during material prep, rivet selection, and installation to achieve professional quality results. With practice, you'll be riveting like an expert in no time. Let us know if you have any other questions! CNC Milling