High Quality Rivets for CNC Machined Parts(removing broken tap Hardy)

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Rivets are a critical component in many CNC machined parts and products. Selecting the right rivets is essential to ensuring strength, durability, and quality in the final product. This article will examine the characteristics of high quality rivets for CNC machining and provide recommendations for choosing the best rivets for your application.
What are Rivets?
A rivet is a mechanical fastener that consist of two main parts - a smooth cylindrical shaft and a head. The shaft is inserted into holes in the materials being joined. The rivet head engages the material on one side while the end of the shaft is peened, pressed, or upset against the other side. This creates a solid joint that is highly resistant to shear forces and vibration.
Rivets come in a wide range of styles, sizes, and materials to accommodate different applications and joint requirements. Some common types of rivets include:
- Solid/blind rivets - tubular rivets with a head on one end. The opposite end is expanded and flattened to create the second head.
- Split rivets - have a pre-cut split at the tail end so they can expand as the tail is flattened to form the second head. Easy to install in hard-to-reach places.
- Drive rivets - designed to be installed in soft materials like plastic and sheet metals. They have a small center hole that allows installation with a hammer rather than specialized rivet equipment.
- Structural rivets - used for critical structural joints and high-strength applications. Made from high strength alloys like steel, titanium, and aluminum.
Benefits of Rivets for CNC Machining
Rivets offer unique benefits for CNC machined parts and products:
- Durable, permanent joints - When installed correctly, the formed heads create solid, permanent joints that maintain clamp load over time.
- Even load distribution - Rivet joints evenly distribute shear and tensile loads across the joined materials. This prevents stress concentrations that could lead to fatigue and failure.
- Allows for dissimilar materials - Rivets can join different metals, plastics, composites, etc. Other fasteners like welding would damage or distort some material combinations.
- Quick, easy installation - Automated riveting equipment allows for fast, efficient rivet installation in mass production environments like CNC machining.
- Non-threaded - Rivets form solid joints without threading or other complex geometry. This makes them suitable for automated processing.
- Lightweight - The small footprint of rivets adds negligible weight versus other mechanical fasteners. This is ideal for products where low mass is critical.
Characteristics of High Quality Rivets
With an understanding of the advantages of rivets, selecting the optimal rivet design and material is key to performance and durability. Here are key characteristics to look for in high quality rivets for CNC machining:
- Tight dimensional tolerances - Diameter, length, head dimensions, and other specifications should adhere tightly to standards to ensure consistent fit and installation.
- Optimized hardness - The rivet must be strong enough to withstand installation and in-service loads without failing or deforming excessively. Hardness should be optimized for the application.
- Tensile strength - Adequate tensile strength is required to prevent the joined materials from pulling apart under load. Verify rated tensile strength meets or exceeds the demands of the particular application.
- Shear strength - High shear strength enables the rivet joints to resist lateral and offset loads without failing.
- Ductility - Ductile materials like certain aluminum alloys allow the set head to form properly rather than cracking during installation.
- Corrosion resistance - Rivets should resist corrosion damage when exposed to weather, chemicals, salt spray, etc. Stainless steel and aluminum are common choices for corrosion resistance.
- Fatigue resistance - Properly designed rivets will remain intact through extensive cyclic loading without cracking or loosening. Verify rated fatigue life meets expected service life.
- Consistent quality - Reputable manufacturers will supply rivets with certified specifications, quality control testing, lot traceability, and minimal defects.
Leading Materials for CNC Machined Rivets
The material used to manufacture the rivet plays a critical role in the fastener’s performance and service life. Here are some of the most common and effective materials for rivets in CNC machined components:
- Aluminum - Lightweight, corrosion resistant, and ductile. One of the most versatile and widely used rivet materials. Ideal for aircraft and other weight-sensitive applications.
- Stainless steel - Offers very high strength along with excellent corrosion resistance. More expensive than aluminum but required for critical high-strength joints.
- Titanium - Extremely strong yet lightweight. Provides top level fatigue resistance combined with corrosion resistance. Used in demanding aerospace and racing components.
- Monel - Nickel-copper alloy with strength approaching steel along with outstanding corrosion resistance. Frequently used in marine and other wet environments.
- Brass - Corrosion resistant and electrically conductive. Used for electronics housings and decorative applications.
- Steel - Strong, durable, and inexpensive. Carbon steel provides high shear strength at low cost but can rust over time.
Proper Rivet Selection and Usage
Choosing the optimum rivet design and material for each unique application requires attention to detail. Always check required mechanical properties versus rivet specifications. Installation method must match rivet style - solid rivets require high force presses while soft materials may allow hammer sets.
Use industry standard best practices for hole sizing, material spacing, and joint design. Consult experts and rivet manufacturers when designing critical assemblies and receiving custom CNC machined components. Validate your selected rivets through prototype builds and testing before full-scale production.
With an understanding of rivet characteristics and materials along with sound design and testing practices, engineers can take full advantage of rivets in CNC machined parts. The result will be products with durable, high-quality riveted joints that withstand the demands of their operating environment. CNC Milling