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THE
SELF-CLINCHING
FASTENER
HANDBOOK
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r e astener story . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2ow and why self-clinching works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3natomy o se -c nc ng . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4ypes of self-clinching fasteners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5mportance o qua ty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6eliability in service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
nsta at on proce ure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8nstallation problems and solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Other considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Questions and Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Glossary of terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12dentification Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
contents
Copyright 2002
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the deathatrevolutionized
productionfastening
hen K.A. Swanstromounded Penn Engineering &
anufacturing Corp. in 1942, he
so w t a revo ut onary new
pro uct: an easy-to- nsta , se -
clinching fastener that provides load-carrying threads in
metal sheets too thin to be tapped.
At first, Mr. Swanstrom produced his innovative design
with four machines in a Doylestown, Pennsylvania
garage. s s mp e operat on soon gave way to
a modern facility in Danboro, Pennsylvania as
manu acturers an eng neers a e recogn ze t e
benefits of self-clinching fasteners. They not only reduced
time, labor, weight and inventory on many assembly jobs,
but they also opened
engineers and design
assortment of thin-met
possible for the first ti
Industry-wide acceptance led to earnest production ofself-clinching fasteners shortly after World War II. As
n ustry s nee to o toget er u tra-t n an u tra- g t
metals grew, so did the product line. Over the years the
or g na se -c nc ng astener es gn evo ve to meet
hundreds of new design applications.
Today, nuts, studs, spacers, standoffs, access
hardware, and other components are used worldwide
by a variety of manufacturers, including producers of
te ecommun cat on, computer, me ca , automot ve, an
aerospace equ pment an systems.
2
advantagesofself-clinchingfasteners: rovi e s ron rea s in me a as in as . . mm. . . .
.
- . .
, .
.
.
Low installed costs.
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ow whyw ere
ouseself-clinchingfasteners
defined, a self-clinching fastener is anydevice, usually threaded, that when
resse nto uct e meta , sp aces t e
ost mater a aroun t e mount ng o e,
caus ng t to co ow nto a spec a y
designed annular recess in the shank or pilot of the
fastener. A serrated clinching ring, knurl, ribs, or hex
head prevents the fastener from rotating in the host
material once it has been properly inserted (see page 4).
Thus, self-clinching fasteners become a permanent part
of the panel, chassis, bracket, or other item into whicht ey are nsta e .
hey also have greater reliability and more holdingower than extruded/tapped or stamped threads. They
are used chiefly where good pullout and torque loads
are requ re n s eet meta t at s too t n to prov e
secure asten ng y any ot er met o . ven t e
sheet is thick enough to sustain tapping, it may actually
e more economical to use self-clinching fasteners
ith gaugeable threads. They can be installed during
abrication to eliminate loose hardware during final
assembly . In fact, the use of self-clinching fasteners
often will allow the use of a thinner sheet. Because ofheir compact design and low profile, they provide for a
eat appearance, too.
s a ru e, a se -c nc ng astener s ou e spec e
henever a component must be readily replaced and
here loose nuts and hardware wont be accessible.
If it appears that the attaching nuts and screws can
e reached after a chassis or cabinet is assembled,
self-clinching fasteners can be installed during metal
abrication and can simplify and expedite component
mount ng an assem y operat ons, ncu ng t ose
erformed in the field.
D E S I G N F O RM A N U F A C T U R E A N D
ASSEMBLY Self-clinchingfastenershelpdesignersmeetDFMAarameterswhichinclude:
Fewerpartstohandle.Hardwaresuchaswashers,lockwashers,andloosenutsarenolongerrequiredinfinalassembly.
Fewerassemblysteps.Sincethetaskofhardwareinstallationisdoneduringfabri-cation,thenumberofstepsrequiredforfinalassemblyisreduced.
Lesstotalassemblytime.Fewerpartsandlessstepsmeanshorterassemblytime.
Allofwhichleadtoshortertimetomarket,improvedqualitythroughassemblysimplification,andreducedoverhead.
SPECIALNOTEFORINSTALLINGINTOSTAINLESSSTEELSHEETS
Oneoftheverybasicsofself-clinchingisthatthefastenermustbeharderthanthehostsheet.Onlythenwillthefastene
performasintended.Thisisparticularlychallengingwheninstallingfastenersintostainlesssteelsheetmetal.
Ifyourapplicationrequiresthatthefastenerclinchesintostainlesssteel,besureyouusethefastenersspecificallydesignedforthispurpose.ConsultPEMBulleitnnSSfor
informationonthsetypesoffasteners.
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he natomo se -c nc ng
Head
Component
Host Metal
Flush Mounted
Flush Mounted Hex Head ProvidesTorque Resistance
Direction ofInstallation Force
Host Metalows n o n ercu
Ribs ProvideTorque Resistance
us oun e
rec on o ns a a on o rce
Host Metalold Flows into
Undercut
rec on oInstallationForce
Serrated ClinchingRing ProvidesTorque Resistance
Back Tapered Shank
omponent
typicalself-clinchingnut
typicalself-clinchingstud
typicalself-clinchingstandoff
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asict esofsel -c nc ngasteners
nuts: uts w t t rea strengt sgreater t an m stee screws
are common y use w erever
strong internal threads are needed
for component attachment or
fabrication assembly.
studs: Externally threadedfasteners which are used where
t e attac ment must e pos t one
before being fastened.
spacers&standoffs:Used where it is necessary to stack
or space components away from thepanel. Thru-threaded or blind types
are generally standard.
ushfasteners: Whennsta e , t ese asteners are
completely ush within the sheet.
Many times these fasteners are
installed into a at sheet so that the
fasteners will not interfere with later
bending and forming operations.
oatingnuts: This fastenercompensates for mating hole
misalignment by having a oating
t rea e e ement.
threadedaccessar ware: Generally used on
enclosures where the screw must
remain with the door or panel.
lockingfasteners: Providea prevailing torque locking feature
to restrict the rotation on the
screw un er a verse con t ons
of vibration. Locking features may
nc u e meta or p ast c types.
non-threadedfasteners:Allow for quick assembly or removal
of components without the need
for screws or additional fastening
hardware.
concealed-head: Installedinto milled, blind holes so that
one s e o t e pane rema ns
unmarred. Studs and standoffs
are genera y ava a e n t e
concea e - ea type.
blind: Have closed ends thatlimit screw penetration and are
useful for protecting internal
components from damage by
inadvertent insertion of extra long
screws. rea s are a so protecte
from damage and foreign matter.
rightangle: Provide youwith strong right angle attachment
points in sheets as thin as .040/
1mm. These fasteners are a
cost-effective replacement for:
bent edge tabs; bent center tabs;
bent anges; angle brackets; tack
we s; an oose ar ware.
cabletie-mount: Self-
clinching tie-mounts are designedto provide secure attachment
points for mounting wire to
electrical chassis or enclosures
without the problems associated
with traditional mounting methods.
sheetjoiningfastener:a self-clinching fastener that joins
two sheets of metal. The fastener
installs smooth with the top sheet,
and ush or sub-ush with the
bottom sheet.
CUSTOMDESIGNS
Sincethereareagreatmanytypesofstandardself-clinchingfastenersavailable,itisusuallypossibletochooseonetome
yourdesignrequirement.Therearetimeshoweverthatacustodesignedandmanufacturedfastenerisnecessary.Ifthisisth
case,PennEngineeringcanassistyouwithyourrequirementtprovideyouwiththebestsolutiontoyourdesign.
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qualityofself-clinchingfasteners
n order request comes to the desk of
the buyer or procurement individual with
the words PEM or equivalent written
next to a specification for self-clinching
fasteners. Although a review of the manufacturers basic
spec cat ons w un ou te y turn up a s opp ng st
of equivalents, a purchase made on the basis of lower
rice alone may prove
more costly in the long
un.
here are significant
ar at ons n t e
mater a s use ,
manu actur ng process,
quality controls and
component dimensions
hat make the same
roduct, made by
different manufacturers,
ery different from one
anot er.
Wire stock is used for the manufacture of many self-
clinching fasteners. Basic blanks are formed on cold
headers or cold formers; subsequent operations such as
p erc ng, r ng, tapp ng, t rea ro ng, an s ott ng may
e requ re .
Self-clinching fasteners are also made from free-
machining, cold-drawn, low-carbon bar stock, a variety
of free-machining and cold-drawn stainless steels,
aluminum and phosphor bronze. They are formed on
automatic bar machines and generally have secondary
operations such as slotting, tapping or lock forming.
n s ng operat ons suc as eat-treat ng an p at ng
are equa y sop st cate , an qua ty contro measures
must be monitored throughout the manufacturing
process.
With so many manufacturing variables to control, there
are several quality areas which must be examined before
choosing the manufacturing of self-clinching fastener for
your app cat on.
ese nc u e:
installedcost...thebottomline
e es ra o us n se -c nc n
,
o era rue c ureo cos . n e ra
,
t ecosto mater a s a oran
over ea mus e ac ore n o e
accura e com ar son w e na
-
astener.Re ectsan s o a e ueto
cos s,so ecer a n a e
ouren neer n s ec ca ons.
DIMENSIONALTOLERANCES: se -c nc ng astener requ res very t g t to erances to max m ze t s per ormance. n apart that is specified with a dimension .010 / 0.254 mm a variation of only .002 / 0.051 mm can make a 20% difference.
THREADFIT:A part may be specified because it meets one or more government specifications for thread tolerances. Ifequivalents are considered, be sure that they meet the same specifications.
PREVAILINGTORQUE:Be sure that parts meet the prevailing locking torque specifications required.
HEATTREATMENT:This is a very critical quality area. Improper heat treatment can cause a fastener to fail during or afternsta at on. mproper temper ng can cause astener r tt eness caus ng t e astener to crac ; na equate treatment can cause
fasteners to be so soft that they are literally crushed during installation.
PLATING:Plating standards set limits for preparation of the metal, plating thickness, adhesion, rust corrosion protection,ours o sa t spray test ng, an ot er operatons. poor y p ate part w m n s t e appearance an per ormance o your
final product.
PERFORMANCE:The fasteners should be tested to meet the manufacturers published performance data. In addition toas c per ormance test ng, e sure t e astener a so meets your requ rements or v rat on res stance, t rea oc ng, eat,
an e ectr ca c aracter st cs.
QUALITYCONTROL:Ensure the fastener manufacturer is ISO 9001 / QS 9000 compliant. This will help assure that all thea ove crter a s e ng met.
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reliabilitnserv ce
ofaself-clinchingfastener
e re a ty o a se -c nc ng astener n
service depends on many factors, beginningith a properly sized hole, the thickness and
hardness of the host panel,
proper installation and design of the
fastener, and the application where the
fastener is used.
ere are t ree tests app ca e to a
se -c nc ng astener to eterm ne ts
reliability in service. The first, called torque-
out, determines the fasteners ability to
resist rotation within the panel. This test
often is made at the head of the fastener
o ten w t va ues excee ng t e u t mate tors ona
strength of the mating screw or nut.
A second reliability measure is pushout.
Pushout values indicate the axial resistan
of a fastener to remove it from the sheet
opposite to the direction from which it wa
nsta e , an s ou e roug y 5 to 10%
of the force used to install the fastener.
A final test is pull-through.(1) Pull-through
is the resistance of a fastener to pulling
through the metal sheet when a clamping
torque is applied.
properlysizedhole
sheetthickness
sheethardness
properinstallation
qualityoffastener
(1) Pull-through generally applies only to self-clinching studs and standoffs and is not shown in this chart.(2) See special note about installing into stainless steel on page 3.
ThreadTestSheetMaterial
Size 5052-H34Aluminum Cold-rolledSteel 300SeriesStainlessSteel(2)
Installation Pushout orque-out Installation Pushout Torque-out Installation Pushout orque-ou
lbs.) kN) lbs.) N) i n.lbs.) Nm) lbs.) kN) lbs.) N) i n.lbs.) Nm) lbs.) kN) (lbs.) N) i n.lbs.) N
2-56 M2 1500-2000 6.7-8.9 90 00 10 1.13 500-3500 11.2-15.6 125 550 15 1.7
4-40 M3 1 500-2000 6.7-8.9 90 00 10 1.13 500-3500 11.2-15.6 125 550 15 1.7 000-5000 13-22 165 725 17 1.
6-32 M3.5 2500-3000 11.2-13.5 95 00 17 1.92 000-6000 13.4-26.7 130 570 0 2.3 000-7000 22-31 170 750 24 2.
8-32 M4 2500-3000 11.2-13.4 105 70 23 2.6 000-6000 18-27 145 645 5 4 000-7000 22-31 180 800 7 4.
10-32 M5 - 11.2-15.6 110 . - 18-38 180 . - - 1025 .
1/4 M6 4 000-7000 18-32 60 1580 90 10.2 6000-8000 27-36 400 1760 150 17 9000-11000 40-48 50 000 150 1
5/16 M8 4000-7000 18-32 80 1570 120 13.6 6000-8000 27-36 420 1870 165 18.7
Generalpushoutandtorque-outvaluesforPEMself-clinchingnuts.(1)
(unifiedandmetricdata)
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ast,simpleinstallationsavestimeandmoneyontheassemblyline.
n just three easy steps, self-clinching fasteners
can be installed with any parallel acting pressthat can be adjusted to optimum installation forces.
nstallationrocedure
Specialconsiderations...
1.Mounting holes may be punched, drilled, or cast;they should not be chamfered or have broken edges in
excess of .005 / .127 mm. Hole tolerances of +.003,
-.000 / +0.08 mm must generally be held. The fastener
should be installed on the punch side if the sheet is .09
/ 2.29 mm or thicker because of the piercing break-to-
die diameter. Holes pierced in sheets thinner than .09 /
2.29 mm may ave asteners nserte on e t er s e. n
all cases, the manufacturers recommended minimum
centerline of hole to edge of sheet distance should be
observed. No deburring or countersinking is required.
2.Installation results in a flush surface on one side of thepanel. Conversely, staked or crimped fasteners require
special counterboring to obtain a one-sided flush surface.
3.When installing, the most important criterion is thatthe fastener must be squeezed into place. A hammer
blow or impact does not allow sufficient time for the
sheet material to flow into the recesses of the shank and
un ercut.
4.Because the installation equipment generates no
excess noise or pollution, the fasteners can be installedanywhere in the production process. No special facilities,
ventilation equipment, or safety procedures are required.
5.When installed using the recommended squeezingforce (depending on the size of the fastener and
hardness of the sheet metal), there is little or no distortion
of the sheet or damage to the finished surface. Fasteners
generally should be installed after plating, finishing, or
ano z ng. t oug , w t a proper p at ng process, t ey
can be installed before plating.
as eners uare n oa rev ous
unc e r e orcas o e.
,
.
.
na ns a ema n ece rom
.
fastenerinstallationDOs...DO provide mounting hole of specified size for each fastener.
make certain that shank (or pilot) is within hole before
applying installation force.
apply squeezing force between parallel surfaces.
apply sufficient force to totally embed clinching ring around
ntire circumference and to bring shoulder squarely in contact
with sheet. For some fasteners installation will be complete when
the head is flush with the sheet.
fastenerinstallationDONTs...DONTinstall steel or stainless steel fasteners in aluminumpanels before anodizing or finishing.
DONTdeburr mounting holes on either side of sheet beforeinstalling fastenersdeburring will remove metal required for
clinching fastener into sheet.
DONTinstall fastener closer to edge of sheet than minimumdge distance indicated in dimension tablesunless a special
fixture is used to restrict bulging of sheet edge.
DONTover-squeeze. It will crush the head, distort threads,and buckle the sheet. Be certain to determine optimum installation
force by test prior to production runs.
DONTattempt to insert fastener with a hammer blow under any circumstances. A hammer blow wont permit the
sheet metal to flow into the back tapered shank.
DONTinstall screw in the head side of the fastener. Installfrom opposite side so that the fastener load is toward the sheet.
The clinching force is designed only to hold the fastener during
handling and to resist torque during assembly.
DONTinstall fastener on pre-painted side of sheet.
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nstallationroblemsandsolutions
Questions? Consult our Applications Engineering department.
problem possiblecause solution
Fastener not seated squarely
re uce o ng power.
Poor holding power fasteners fallout of panel.
Threads tight sheet buckles.
Poor holding power nut off center
o o e .
Tight threads, cracked.
Panel buckles badly with studin .040 to .059 (1 to 1.5 mm)
mater a .
Poor holding power of standoffs orstuds in panel.
Head of flush-head stud or standoffcups.
Poor holding power.
Edge of panel bulges.
Punch and anvil faces are not
para e .
Panel cocked during installation.
Inadequate installation force. Panel too hard for fastener
material.
Countersunk hole in panel.
Fastener over-squeezed.
Oversize mounting hole.
ut s coc e n o e an s ears
side of hole when installed.
Shank length extends throughsheet.
Lack of countersink in anvil.
o e n anv too arge orchamfered.
Punch diameter too small or notar an at.
Die side of panel thicker than
.093/2.36mm may have holetoo large for fastener due tonecessary punch and die
c earance.
Mounting hole violates specified
minimumn edge distance.
ut s over-squeeze .
Ensure that punch and anvil areflat and parallel and hard. Ensure that large panels are held
perpendicular to punch and anvi
Seat fastener against shoulder
by applying more force or
changing shut height of press. Specify appropriate fastener
material for sheet hardness, i.e.stainless steel (see note on page 3)
Do not countersink or deburr hol
Reduce installation force.
Punch or drill hole to specified
dimensions. Check that shank of nut is
squarely in hole before squeezin
Choose fastener with proper
shank length for sheet thickness
rov e counters n n anv tospecified dimensions.
se anv w t o e per cata og
dimensions.
Punch must be larger than head
of stud or standoff and preferab
equal to anvil diameter.
unc o e un er s ze an ream
to catalog dimensions or changtooling to punch from opposite
side of panel.
estra n pane or rac et n
fixture during installation or movmount ng o e away rom e ge.
Reduce installation force if possibl
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otherconsiderations
AUTOMATEDASSEMBLY
Since all self-clinching fasteners must be squeezed into place, any press or vise that
provides the necessary parallel force may be used to install them.
A PEMSERTER automated press should be considered for high volume installations.
PEMSERTER presses are specifically designed to feed self-clinching fasteners
automatically into punched or drilled holes in sheet metal, seating them correctly
with a parallel squeezing force. Feeding rates are five to six times faster than manual
insertions, and installation force is adjustable to compensate for variations in thickness
an ar ness o t e s eet an t e e g t o t e asteners.
Our equipment capabilities now incorporate smart tooling andsoftware, automation, robotics integration, and in-die installation
with the PEMSERTER in-die fastener feeding system which brings
new dimensions to stamping capabilities and incorporates the latest
technologies to deliver the performance that is needed to compete in
t e g y compet t ve stamp ng n ustry. t e m nates t e secon ary
operations typically required for fastener insertion, thus reducing overall
a or costs, mprov ng part qua ty an ramat ca y mprovng pro uct
through put.
FASTENERSFORNON-
DUCTILEMATERIALS
With the arrival of P.C. boards, plastics and
other fabricated materials, a need emerged for
a fastener which would offer the same benefits
as self-clinching fasteners but work effectively
in these non-ductile materials. To address this
requirement, PennEngineering
offers PEM broaching fasteners
an ee ast SMT surface mount
asteners.
A broaching fastener is any knurled
shank fastening device that is
pressed into a punched or drilled hole to
provide a strong threaded attachment point
in a non-ductile material. Specially formed
axial grooves around the shank of the fastener
broach or cut into the material, creating a
firm, interference-type fit, resistant to
rotat ons.
ee ast SMT fasteners mount
to P.C. boards in the same manner as
other surface mount components
prior to the automated reflow solder
process.
Regardlessoftheself-clinchingfastener
youchoose,itisalwaysrecommended
thatyouobtainsamplestodoyourowntesting.
Theintegrityofyourproductdependsontheperformanceandqualityof
thesefasteners.
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answersothetenmost
commonlyasked uestionsaboutself-clinching as eners
QDoestheshapeoftheself-clinchingfastenerchangeduringinstallation?A o, the fastener does not deform in any way. Thereis no flaring, crimping, swaging, peening or rivetingnecessary._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
QWhatholdsthefastenerinthesheet?A he squeezing force on the fastener causes thes eet mater a eneat t e ea to co ow nto t e
back-tapered shank or undercut of the fastener securelylocking it in place._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
QDoIneedspecialequipmenttoinstallself-clinchingfasteners?
A o. Self-clinching fasteners are installed usingany type of parallel acting press which will squeeze thefastener in place._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
QWontthesefastenersfallout,twistout,orspinintheirmountingholesifItightendowntoohard?
A o. yp ca torque-out va ues are genera y qu tehigh compared to the rotational force that will be puton them. In fact, for most quality self-clinching nuts, thescrew will fail before the nut rotates in the material._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
QCanIinstallaself-clinchingfastenerwithahammerbloworsimilarforce?
A o, a self-clinching fastener must be installedus ng a squeez ng act on. qu c mpact nsta at on
will not allow sufficient time for the sheet material to coldflow._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
QIwouldliketoreplacesomeoftheweldedfastenersInowuseinmystainlesssteelfabrications.Isthereaself-clinchingfastenerthatwillgointoastainlesssteelsheet?
A es. Self-clinching fasteners for stainless steelapplications are available. These fasteners are generallymade from specially hardened stainless steel and willinstall into sheets up to HRB 88 in hardness.
QWhenusingself-clinchingfasteners,whataremypanelrequirements?AGenerally, there are two basic requirements.
irst, the panel must be a ductile material softer thanhe fastener which is going into it. Second, the panel
must meet the minimum sheet thickness required by tharticular fastener. Some self-clinching fasteners cane installed into sheets as thin as .020/0.51mm, but
generally .030/0.76mm or .040/1mm is the minimums eet t c ness necessary._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
QIsthereamaximumsheetthicknessIshouldbeconcernedwithbeforespecifyingself-clinchingfastenersAGenerally, there is no specified maximum thickneor sheets. However, because of their special design anunction, a few fastener types do specify a thicknessange which includes a maximum._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
QInoticesomeofthefastenershaveahexagonalshapedhead.DoIhavetopunchahexagonalmountingholetoinstallthese?
ANo. All self-clinching fasteners are installed intoa round punched or drilled hole. A hexagonal head wilcause the sheet material to cold flow around the head
rov e g torque-out res stance. e ex ea w lush in the sheet when installed._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
QCanIinstalltheseblind,fromoneside,ifIdonthaveaccesstobothsidesofthesheet?
AGenerally, you must have access to both sidesof the sheet to properly install self-clinching fasteners.
owever, there are some 1/4/M6 or larger nuts whichcan be drawn in from one side using an impact-torque
rench. For information on blind threaded inserts for onsided access installation go to www.pemnet.com.
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anvil- n nsert, e t er so or o ow, w c s use on t e un ers e o apane to res st t e nsta aton orce.
blind- oe , usua y t rea e , w c s open rom ony one en .
broaching- e act o cuttng a s ape n any o ect y usng a man re os m ar s ape. s app e to asteners, t e way a nure s an roac es
ts way nto t e mount ng o e.
captive- e a ty o a astener to reman secure y attac e to a pane .
captivescrew- ee: pane astener.
chamfer- eve e e ge or corner.
coldflow- e movement o a uct e mater a un er pressure.
concealed-head- type o astener w c , w en nsta e , s competeyen w en vewe rom t e reverse s e.
ductile- eta w c s not r t te an can e eas y orme or ent.
floating- e a ty o a astener to move n a rect on para e to t emount ng pane an a ow or mat ng o e m sa gnment.
flush- he ability of a fastener to be contained completely within thethickness of a panel. Also refers to the absence of a protrusion above thesurface of the panel.
head-The portion of a fastener which forms its largest diameter.
installationforce-A term expressed in pounds, tons, or newtons appliedxially to a self-clinching fastener to achieve proper installation.
interferencefit- he insertion of one member into another whose diameteris slightly smaller than the part being inserted.
knurledclinchingring-The displacer portion of a fastener which hasorrugations and is used to develop torque resistance when installed in sheet
metal.
lockingelement-A device employed to restrict rotation of a threadedmember while operating in adverse environments, such as vibration andtemperature. The nut-locking element provides prevailing locking torque to themating screw.
minimumdistance-The minimum distance from the center of a fastenermounting hole to the nearest edge of a panel which will keep the edge fromdeforming. This distance may be reduced by suitable fixturing or increasingthickness of panel material.
minimumsheetthickness-The thinnest section of a panel, usuallymeasured in thousandths of an inch or millimeters, into which a fastener may
properly be installed. The same fastener may be installed in panels having anythickness greater than minimum.
mountinghole-A properly-sized round opening in a panel to receive theshank of a self-clinching fastener.
panelfastener-A threaded screw which is held captive to a panel andwhich, when disengaged from its main nut, remains fixed to that panel.
pin-A captive post that extends from a panel.
plungerassembly-A spring-loaded device used for latching or indexingpurposes.
positivestop- v sua n cat on t at t e proper ept o penetrat on ot e nure rng as occurre or w en t e ea s n contact w t t e topsur ace o t e pane . ynonym: s ou er.
pull-through- e resstance o a astener to a orce app e n t e samerecton to w c t was nsta e .
punch- mova e nsert, e t er so o o ow, w c app es an nsta at o norce to t e top o t e astener.
pushout- e orce requre to remove a astener rom a pane n a rect onoppos te to t e way rom w c t was nsta e . ote: us out s expresse npoun s or newtons.
rockwellhardness- reatve measure o ar ness. oc we cae suse or ar mater a s, oc we or soter mater a s, suc as s eet meta .
self-clinching- e met o y w c a astener s securey attac e to as eet o uct e mater a y causng t e mater a to co ow un er pressurento an annuar recess o t e astener t ere y securey oc ng t n pace.
self-locking- oc ng e ement, orme as an ntegra part o a astener,w c prov es orce to restrc t t e rotat ona movement o a t rea e mem er.
shank- e por ton o a astener, w c s s g t y sma er t an t e astenersmounting hole and provides a positive location for the fastener in the hole. Ashank also incorporates an annular groove which becomes filled with panelmaterial as the fastener is installed, and the retention of this material providespushout resistance.
shanklength-The actual length of that portion of a fastener which isembedded in the panel material.
shoulder-The surface area of a fastener which contacts the top surface ofthe sheet material. See: positive stop.
spring-loaded- device having a separate moveable component that is
biased in one direction by a spring.
standoff-A tubular device, usually threaded, for spacing or stackingomponents.
stud-A male threaded captive post that extends from a panel.
swaging-An operation whereby a reduced diameter of a fastener isdeformed to secure it to a panel. Note: the antonym of swaging is self-clinchingwhere the panel material is caused to deform.
threadclass- measure of clearance or fit between the screw and the nuttaken at the pitch diameter.
threadedinsert-A threaded device which is installed in a panel material.
throughhole- hole, threaded or unthreaded, which transverses theentire length of a part and is usable from either end.
tolerance-The absolute amount of maximum or minimumdimensional deviation allowed that will not affect the performance of amechanical part.
torque-out- he amount of torque necessary to spin the fastener out of thesheet. This is torque applied to the fastener. No axial load is applied.
torque-through-The amount of torque necessary to fail the fastener inxial load.
undercut-The reduced diameter of a fastener which receives sheetmaterial when a fastener is installed. Depending on the type of fastener, maybe rectangular or back tapered in shape.
glossaro terms
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PEM fasteneridenticationtrademarks
o help you identify genuine PEM brand fasteners, most are marked by one of our registered trademarks.
Genuine PEM brand fasteners can only be purchased from one of our authorized worldwide distributors. For
a complete list of these distributors, check our web site: www.pemnet.com or call us at our main office.
TwoGrooveonNuts,Standoffs,andPlungers
RecessedDimpleonStuds,Pins,PanelFasteners,KEYHOLEandSNAP-TOPStandoffs
PEMStamponNutsandHYBRIDPanelFasteners
BlueNylonLockingElementonPEMHEXLockingNuts
DoubleSquaresonFloatingFasteners ThePEM300IdenticationMarks
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