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Does
the shape of the self-clinching fastener change during installation?
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No,
the fastener does not deform in any way. There is no flaring,
crimping, swaging, peening or riveting necessary.
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What
holds the fastener in the sheet? |
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The
squeezing force on the fastener causes the sheet material beneath
the head to cold flow into the back-tapered shank or undercut
of the fastener, securely locking it in place.
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Do
I need special equipment to install self-clinching fasteners?
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No.
Self-clinching fasteners are installed using any type of parallel
acting press which will squeeze the fastener in place.
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Won't
these fasteners fall out, twist out or spin in their mounting
holes if I tighten down too hard? |
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No.
Typical torque-out values are generally quite high compared to
the rotational force that will be put on them. In fact, for most
quality self-clinching nuts, the screw will fail before the nut
rotates in the panel material.
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Can
I install a self-clinching fastener with a hammer blow or similar
force? |
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No,
a self-clinching fastener must be installed using a squeezing
action. A fast impact installation will not allow sufficient time
for the sheet material to cold flow.
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I
would like to replace some of the welded fasteners I now use in
my stainless steel fabrications. Is there a self-clinching fastener
that will go into a stainless steel panel?
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Yes.
Self-clinching fasteners for stainless steel applications are
available. These fasteners are generally made from a specially
hardened stainless steel and will install into sheets up to HRB
88 in hardness.
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When
using self-clinching fasteners what are my general panel requirements?
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Generally,
there are two basic requirements. First, the panel must be a ductile
material softer than the fastener which is going into it. This
is why the PEM catalog lists a MAXIMUM panel hardness for
each fastener type. Second, the panel must meet the minimum sheet
thickness required by the fastener. Some self-clinching fasteners
can be installed into sheets as thin as .020" (0.51 mm),
but generally .030" (0.76mm) or .040" (1mm) is the minimum
thickness necessary.
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Is
there a maximum sheet thickness I should be concerned with before
specifying self-clinching fasteners? |
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Generally,
there is no specified maximum sheet thickness limitation. However,
because of their special design and function a few fastener types
do specify a thickness range which includes a maximum.
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I
notice some of the fasteners have a hexagonal shaped head. Do
I have to punch a hexagonal mounting hole to install these?
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No.
All self-clinching fasteners are installed into a round punched
or drilled hole. A hexagonal head will cause the sheet material
to cold flow around the head to provide high torque-out resistance.
The hex head will be flush in the sheet when installed.
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Can
I install these blind, from one side, if I don't have access to
both sides of the sheet? |
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Generally,
you must have access to both sides of the sheet to properly install
self-clinching fasteners. However, there are some 1/4" (M6)
or larger nuts which can be drawn in from one side using an impact-torque
wrench.
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