Quarter Turn - PA-3500 Line
 Manufactured in the United States of America! |
Captive quarter-turn stud assemblies with multiple hole receptacle rails.
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On-Line Product Selector
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- Type 3506-SC stud assemblies consist of a stud and coil spring captive in a steel cup. The assemblies are installed by flaring the end of the cup neck into a countersunk panel hole. Stud locking action compresses the spring, exerting a clamping force on the fastened parts. In locking, the stud spiral cam engages a rigid wire which is offered by the receptacle. MIL-F-25173A* approved.
- Type 3522-S stud
assemblies provide a nearly solid lock without allowing the sheet
separation that occurs with 3506-SC assemblies while under
tensile overload sufficient to overcome the expansion force of
their springs. With 3522-S assemblies, the stud cam first
quarter-turns onto the receptacle wire under spring tension
supplied by a curved washer. Further locking rotation then starts
to turn the cammed fastener head around a stud cross-pin. The
head is moved downward as it turns, compressing a coil spring
which is stronger than the curved washer, and finally compressing
the curved washer flat. At the fully-locked position, the assembly
has no remaining spring movement achievable by tensile overload.
3522-S assemblies are not MIL-F-25173A approved.
CAUTION: Any external factor that prevents the stud from turning with initial locking torque could allow the fastener head to rotate first. This could convey an erroneous impression of locking while the stud cam has not locked onto the receptacle wire. All operators of this special purpose fastener should be trained to recognize proper stud cam locking.
- Standard receptacles The PA-3500
Line receptacles come in both single hole and strip
configurations. The strip configuration acts as a supporting
frame for the panels or removable parts to be fastened, with
continuous holes for stud engagement and rivet mounting on
3/8" centers. The strip is riveted to a support member and
the stud panel rests against the strip face having the stud
holes. The strips are aluminum alloy with a continuous rigid
stainless steel wire staked across the underside of the stud
holes. The fastened panel rests on the strip and its captive
quarter-turn studs engage the rigid wire.
Custom cut lengths of 3590 and 3595 strips may be specially ordered. The part callout system for cut lengths assumes standard hole spacing and location of the holes at each end at the standard distance from the end.
* Meets the design, physical and performance requirements of MIL-F-25173A. However, full mechanical properties testing may not be performed on each production lot.