What is meant by a blind protrusion?

In the context of fasteners, a blind protrusion refers to a type of rivet that is installed into a hole and expands from one side, creating a large blind or headless end on the opposite side. This type of rivet is typically used when access to the opposite side of the material being fastened is limited or unavailable.

Here's how a blind protrusion rivet works:

1. A hole is drilled into the material to be fastened.

2. The blind protrusion rivet is inserted into the hole from one side.

3. A tool or riveter is used to pull the mandrel of the rivet, causing the rivet to expand and form a large blind head on the opposite side.

4. The mandrel breaks off, leaving the rivet permanently installed.

Blind protrusion rivets are often used in applications where strength and durability are important, such as in the automotive, aerospace, and construction industries. They are also commonly used in applications where space is limited or where access to the opposite side of the material is restricted.