December 16, 2008
PEM® SpotFast® fasteners, paired with a specially designed wave washer, allow attachment of two thin metal parts in applications requiring repeatable pivoting or hinging action. These self-clinching fasteners (Type SFW) from PennEngineering® permanently join the two metal components to create a flush-attachment connection without protrusions on either side. The compatible wave washer delivers consistent torsion to promote repeatable hinging action while the attachment remains secure.
The steel fasteners have zinc plating with integral lubricant to promote smoother operation. They can join dissimilar metals or sheets with different thicknesses and install in steel or aluminum sheets as thin as 0.031 in. with hardnesses of 80 or less on the Rockwell B scale.
Installation is achieved by preparing a properly sized hole in both panels, installing the fastener in one panel, placing the wave washer over the installed fastener, and then situating the second panel over the fastener. Sufficient squeezing force permanently installs the fastener smooth with the top sheet and flush or subflush with the bottom sheet. The wave washer contributes consistent force for rotation of the top sheet.The fastener's flush profile upon installation creates unobtrusive attachment requiring minimal space, the company reports. A smooth surface is retained for finishing, and fasteners can be concealed with paints or powder coatings.
The fasteners with wave washers are RoHS-compliant and available in various diameters and sizes. Detailed specifications (Bulletin SFW) and free part drawings (PEM CAD Library) can be accessed at the manufacturer's Web site.