Comparing Permanent and Nonpermanent Fastening Methods

 

 

Joint Characteristic

Cost

 

Articulation

Clamp load

Low profile

Vibration resistance

Hole fill

Aesthetics

Fastener

Machining

Equipment

Labor

Overall

Tenon + orbital
or spiral forming

Best

Good

Best

Fair

Fair

Best

Best

Fair

Good

Good

Good

Tenon + hot upset
forming

Poor

Best

Best

Best

Best

Fair

Best

Fair

Poor

Good

Good

Solid rivet +
impact riveting

Poor

Fair

Best

Good

Best

Good

Good

Best

Fair

Best

Good

Semitubular rivet +
impact riveting

Good

Fair

Best

Fair

Fair

Good

Good

Best

Good

Best

Best

Rivet  + orbital
or spiral forming

Best

Fair

Best

Fair

Fair

Best

Good

Best

Good

Good

Good

Rivet + hot upset
forming

Poor

Best

Best

Best

Best

Fair

Good

Best

Poor

Good

Good

 

Bolt and nut,
formed

Poor

Best

Fair

Good

Poor

Poor

Poor

Best

Fair

Poor

Fair

Bolt and nut

Fair

Best

Fair

Good

Poor

Poor

Poor

Best

Good

Fair

Good

Stud and nut

Poor

Best

Fair

Good

Poor

Fair

Poor

Good

Good

Fair

Fair

Screw

Poor

Good

Best

Fair

Poor

Good

Fair

Good

Good

Fair

Good

Retaining ring

Best

Poor

Poor

Poor

Poor

Good

Poor

Best

Best

Poor

Good

Cotter pin

Best

Poor

Poor

Poor

Poor

Poor

Poor

Best

Best

Poor

Good

 

Every application is different, and there is no “one size fits all” solution for permanent part assembly.

This matrix rates permanent and nonpermanent fastening processes for various joint requirements. For these ratings, we examined the lowest cost and least number of machining steps to achieve the requirement in the simplest way possible. For example, a low-profile joint can be achieved with a countersink or counterbore—at the cost of extra machining. Similarly, aesthetics are greatly determined by the type of fastener and its coating or finish, which greatly impacts its cost. A retaining ring or cotter pin is a more expensive fastener, compared with a rivet, especially if that cost includes a mating pin with a groove or through-hole. Overall cost considerations include the fastener, machining, equipment and utilities, and labor costs.

All cost estimates are relative to each other across processes. For example, a tenon has no fastener, and therefore, no fastener cost relative to a rivet or bolt, but a machined tenon has a greater machining cost than a through-hole for a rivet or bolt. A tenon formed as a casting would result in a different costing analysis.