Sheet Metal Fasteners

Sheet Metal Fasteners• What scientific principle defines a fasteners

strength?• What are the three ways we can connect

sheet metal?• Why are some methods preferable to others?

How do fasteners work?• Fastener strength is dependent on surface

area.• Mechanical fasteners rely on clamping force

Sheet Metal Fasteners• The three ways to fasten sheet metal are:– Mechanical Fasteners– Welding– Adhesives

Mechanical Sheet Metal Fasteners• Threaded Fasteners• Rivets

Threaded Fasteners• Screws - A headed threaded fastener that is

designed to be used by forming its own threads.

• Bolt - A bolt is the term used for a headed fastener having external threads that meet an exacting, uniform bolt thread specification

Threaded Fasteners

Rivets• a rivet consists of a smooth cylindrical shaft

with a head on one end. The end opposite the head is called the buck-tail. On installation the rivet is placed in a punched or drilled hole, and the tail is upset, or bucked (i.e., deformed), so that it expands to about 1.5 times the original shaft diameter, holding the rivet in place.

Rivets

Welding

• Spot• MIG/TIG

Spot Welding

• contacting metal surfaces are joined by the heat obtained from resistance to electric current.

MIG/TIG Welding

• contacting metal surfaces are joined by the heat obtained from the electric arc.

Spot Weld With a MIG

Adhesives

• Epoxy – Simply put, epoxy is a two part, very high strength, glue.– Two parts:• Resin• Hardener

Sheet Metal Epoxy Application

Conclusion• How has the Industrial revolution effected

fasteners?• What type of fastener or fastening system do you

think would be the:• Strongest: • Fastest to install: • Best looking: • Most permanent: • Easley removed: • Require “special tools”: