Rivets in Sheet Metal - A Guide to Proper Installation and Use(machining tolerance standards Evan)
- source:ZIEG CNC Machining
When properly installed, rivets create durable and secure sheet metal assemblies. However, the process requires care and the right tools to ensure rivets function as intended. This guide will cover the basics of riveting sheet metal, including proper rivet selection, hole creation, rivet setting, and best practices.
Choosing the Right Rivet
Many factors determine the ideal rivet for an application, including:
- Sheet thickness - Thicker materials require longer rivets. The rivet length should be at least 2 times the combined thickness of the materials.
- Rivet head style - Options like flat head, round head, and countersunk head rivets suit different aesthetics.
- Material - Rivet material should match the sheet metal. Steel and aluminum are common.
- Strength - The rivet strength rating should match the demands of the application.
When in doubt, consult a rivet manufacturer's specifications before purchase. This ensures you select a properly sized and styled rivet for the sheets you plan to join.
Drilling Rivet Holes
With the right rivets on hand, the next step is to drill holes for rivet placement. Here are some tips:
- Use a drill bit slightly smaller than the rivet shaft diameter. This allows the rivet to slide through the hole while still fitting snugly.
- Ensure holes align precisely on both sheets so the rivet shafts insert cleanly from one side through to the other.
- Drill straight, perpendicular holes - angled holes make rivet setting difficult and weaken the joint.
- Add a chamfer around the hole edge to help guide rivet insertion.
- Space holes appropriately based on rivet size, sheet thickness, and application loads. Follow any relevant building codes.
- Deburr holes thoroughly after drilling to remove sharp edges.
Proper hole placement and drilling prevents problems when setting rivets. Now the sheets are ready for assembly and permanent joining.
Setting the Rivets
With aligned holes drilled in the sheet metal pieces, it's time to install the rivets. This requires a riveting tool, rivet set, and bucking bar. The basic process is:
1. Insert the rivet into the aligned holes from one side of the sheet assembly. The rivet head should rest flush against the metal.
2. Position the rivet set against the rivet head. Place the bucking bar on the protruding shaft end.
3. Compress the tools toward each other using the riveting tool. This expands and locks the rivet in place.
4. Check that the set rivet head is tight against the sheet and the shaft end is deformed outward for a solid setting.
5. Repeat for the remaining rivet holes.
For best results:
- Use the properly sized rivet set and bucking bar for the rivets. Improper tools can damage rivets.
- Set rivets straight and avoid bending the protruding shaft.
- Set rivets in a star pattern rather than one area at a time. This evenly spreads force across the metal sheets.
- Take care around hole edges to prevent cracking or deforming the sheets.
- Set each rivet fully until the heads on both sides are tight against the metal.
Proper technique and quality riveting tools are critical for securing rivets that will last.
Riveted Sheet Metal Assembly Best Practices
Beyond proper hole drilling and rivet setting, a few additional tips will produce professional, durable sheet metal assemblies:
- Clean metal joint areas to remove grime and achieve maximum rivet adhesion.
- Use washers under rivet heads and shafts where necessary to reinforce the joint and distribute load.
- Apply sealant around final riveted areas if the assembly will be exposed to moisture. This prevents corrosion around rivets over time.
- Inspect the finished assembly and test for rigidly - adjustments may be needed to tighten up loose joints.
- Touch up scratches, gaps, or other imperfections around rivets using appropriate paint or other coatings.
Though riveting requires practice, when done correctly, the result is an incredibly strong yet reversible mechanical connection. Rivets allow sheet metal fabricators and technicians to construct products and structures that withstand hard use and last for years. By understanding proper rivet selection, precision hole drilling, controlled setting, and best practices, anyone can achieve expert-level riveted sheet metal assemblies. CNC Milling CNC Machining