Installation Sequence - Double Action ("-" code)
Typical double action installation sequence
Step 1: The pre-assembled fastener is inserted into the prepared hole. The installation tool bears on the sleeve head while the internal chuck jaws grip the spindle's pintail. When the tool is actuated the spindle is pulled into the sleeve causing the extruding land to expand the sleeve to fill the hole.
Step 2: When the head of the spindle comes in contact with the sleeve head the extruding land has passed through and a blind head is ready to be formed.
Step 3: As the spindle is pulled the blind head is being formed and the spindle shank is filling the sleeve.
Step 4: when the spindle shoulder comes in contact with the sleeve counterbore the spindle load builds up signaling the tool to shift at the preset shift pressure and then drives the lock collar into the cavity that’s now in alignment.
Step 5: As the spindle load builds up the pintail is separated from the installed fastener leaving an installation with a flush surface that often does not have to be shaved for aerodynamic surfaces.
MLS blind rivet material designation:
"B" indicates Aluminum, "M" indicates Monel & "EU" indicates A-286 CRES