PA-3500 Line Fastener Product Selector

DFCI PA-3500 Line features captive, flare-in stud assemblies and continuous receptacle strips with both stud and rivet holes on 3/8" centers.

The captive stud assemblies are offered in a range of neck lengths for flare-installation into standard gage enclosure panels.

The receptacle strips are installed to frame out the console opening, serving as offset supports for the stud panel. Continuous stud holes and and installation rivet holes are available every 3/8".

1/4-turn fastening action offers operating convenience, predictable clamping force, and locked vibration resistance. PA-3500 Line fasteners combine those features with the versatility of continuous and closely-spaced panel fastening points, and the ease of flare-in stud installation.

1. Select a fastener stud:

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Type 3506-SCxxxA-C3C 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.


Locking Tension: 15 lb
Rated Tensile and Shear: 200 lb when used with DFCI receptacles.
Max. sheet separation under tensile overload: 3/64"
Wear endurance: 5000 use cycles.

Stud: Heat treated carbon steel
Spring: Spring temper music wire
Cup: Mild steel

Type 3522-Sxxx-C3C stud assemblies provide a nearly solid lock without allowing the sheet separation that occurs with 3506-SCxxxA-C3C assemblies while under tensile overload sufficient to overcome the expansion force of their springs. With 3522-Sxxx-C3C 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.


Locking Tension: Variable, up to 200 lb
Rated Tensile and Shear: 200 lb when used with DFCI receptacles.

Cup is mild steel, all other components are heat treated carbon steel.

2. Select a finish
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3. Enter the Panel Thickness:

4. Click on the "Calculate" button to see the resulting part numbers.

Every effort has been made to verify the accuracy of the calculations in this program. However, your application may be unique and not allowed for in the software. The calculations should be verified with an authorized sales engineer before purchasing the parts for your specific application.

Your Specifications Your Results
Stud Part Number
Panel Cup DIM B

Note: Our calculations assume that the locked stud panel will contact a DFCI receptacle strip having a wire depth of .150".

If you encounter any difficulties with this software, please send me an email outlining the problem and I will address the difficulty. As the software sees more use, I will be posting a frequently asked questions page to address the most common issues. mailbox

* Meets the design, physical and performance requirements of MIL-F-25173A. However, full mechanical properties testing may not be performed on each production lot.