Riveting in Sheet Metal Fabrication(what is climb milling Horace)
- source:ZIEG CNC Machining
What is a Rivet?
A rivet is a short metal pin that has a head on one end. The end without the head is called the shank. To join materials, the shank is inserted through aligned holes in two or more pieces of sheet metal. The shank end is then hammered and forms another head to clamp the materials together.
Rivets are commonly made from aluminum, steel, copper, or monel. They come in a variety of head shapes and sizes to suit different applications. Some common head shapes are round, brazier, countersunk, and universal. Rivet diameters range from 1/16 inch to over 1 inch. The material and head shape depends on the type of metals being joined and the strength required.
Benefits of Riveting
There are several advantages to riveting over other mechanical fastening methods:
- Strong Joint - The force created when the rivet shank is hammered outward creates a tight clamping force between materials. This makes a solid, permanent joint.
- No Heat Needed - Riveting can join dissimilar metals without heat, avoiding potential warping or damage from high temps. It also allows riveting of pre-painted or sensitive materials.
- Vibration Resistant - Rivet heads increase surface contact area, allowing the joint to better resist shock and vibration forces.
- Quick Installation - Riveting is generally faster than welding or screwing. It just requires drilling holes and hammering the rivets.
- Less Skill Needed - Basic training is all that's needed for rivet installation. Welding requires more operator skill and training.
- Inspection and Repair - Installed rivets are easy to visually inspect. Defective rivets can be drilled out and replaced. Welds typically require more work to re-do.
Uses of Riveting
Riveting has traditionally been used in aircraft and shipbuilding. It is still the preferred method for assembling airplane fuselages and boat hulls from aluminum sheets. Rivets allow flexibility in these structures while providing strong, reliable joints.
In manufacturing, riveting is common for joining sheet metal fabrications like:
- Automotive panels, doors, and hoods
- Truck cabs and trailers
- Building roofs, siding, and HVAC ducts
- Electronic enclosures and chassis
- Storage tanks and pressure vessels
- Furniture frames and shelving
- Appliance housings and panels
Rivets are also used to attach hinges, brackets, handles and other hardware to sheet metal assemblies.
Rivet Joint Design
Proper rivet spacing, edge distance, and hole size are important design factors for a strong joint:
- Rivet Spacing - Rivets along a seam are spaced 3-4 times the rivet diameter apart for single row joints. Double row staggered spacing reduces to 2-3 times diameter.
- Edge Distance - Distance from rivet hole to sheet edge should be at least 1.5 x rivet diameter to avoid edge tearing.
- Hole Diameter - Drill sheet holes 0.05-0.1mm larger than rivet shank to allow easy insertion. Rivet fills hole during hammering.
- Material Thickness - Maximum grip length of rivet shank should be 4 times the thinnest sheet thickness. Use smaller rivets for thinner materials.
While some hand riveting is still done, most riveting today is automated using pneumatic squeezers or impact rivet guns. The basic process steps are:
1. Sheet Preparation - Sheets are cut to size and holes are punched or drilled along the joint pattern. Deburring removes sharp edges.
2. Hole Alignment - Sheets are aligned and clamped to ensure rivet holes match up.
3. Rivet Insertion - The correct length rivet shank is inserted through the sheet holes.
4. Rivet Hammering - The protruding shank is hammered using the rivet gun to form the second head.
5. Inspection - The riveted joint is checked to ensure head formation is correct with no cracking.
6. Finishing - Any minor burrs are removed. The joint may be cleaned and sealed if needed.
For large rivets, a bucking bar is held against the rivet head while hammering the shank to prevent sheet distortion. Access limitations may require one-sided blind rivets instead of solid shank rivets.
Here are some tips to achieve good results riveting sheet metal:
- Use the recommended drill size based on rivet diameter for easy insertion.
- Make sure sheets are clean and free of burrs before riveting to prevent poor fit-up.
- Clamp sheets securely and check alignment before inserting rivets.
- Make sure rivet gun foot is perpendicular to rivet head during hammering.
- Apply heavy pressure when starting to buck rivets to prevent bending the shank.
- Stagger rows for multiple row rivet patterns to maximize joint strength.
- Always use the shortest length rivet that will fit the material thickness.
- Inspect each rivet after hammering and re-work any poorly formed heads.
Riveting remains a reliable and efficient method for fastening sheet metals in manufacturing and construction. With attention to proper joint design and riveting technique, strong and durable riveted connections can be consistently achieved. The simplicity and flexibility of riveting ensure it will continue being a go-to joining process. CNC Milling CNC Machining