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SkyLoc QL4C Grommet Series
Load Distribution | Panel Protection | 304 Stainless Steel | Multiple Grip Ranges
Technical Overview
The QL4C grommet series provides essential load distribution and panel protection for quarter-turn fastening systems. Manufactured from 304 stainless steel and heat treated to Condition A, these grommets distribute fastener loads across a wider panel area, reducing stress concentration and preventing panel damage. Available in three grip ranges (-1G, -2G, -3G) to accommodate various panel thicknesses from .075" to .155", the grommet series features a precision-formed cup design that interfaces between the stud head and panel surface. Two finish options are available: passivated for general aerospace applications (QL4C-XG) and cadmium plated Type II, Class 2 for enhanced corrosion protection (QL4C-XG-CAD).
Specifications
| Nominal Size: |
1/4" |
| Material: |
304 Stainless Steel |
| Heat Treatment: |
Condition A |
| Grip Range Coverage: |
.075" – .155" (dash number dependent) |
| Diameter (A): |
.505" max |
| Center Hole (C): |
.255" / .250" |
| Reference Dimension (E): |
.310" |
| Compatible Systems: |
QL4S Series Quarter-Turn Studs |
| Equivalent Part Numbers: |
CA21038-4 Series, CA21038C-4 Series |
| Compliance: |
AS9100D Certified, CAGE Code 435Z0 |
Applications
- Aerospace: Composite panels, thin-gauge sheet metal, applications requiring load distribution to prevent panel dimpling or stress cracking
- Motorsport: Carbon fiber bodywork, lightweight panels, high-vibration applications requiring load spreading
- Industrial: Thin panel installations, equipment enclosures, applications requiring surface protection from fastener bearing loads
- Marine: Deck panels, thin-wall structures in corrosive environments requiring load distribution and panel protection
- Defense: Military aircraft composite structures, lightweight panels requiring optimized load distribution
Grommet Variants
| Part Number | Grip Range | Finish | Equivalent Part |
| QL4C-1G |
.075" – .095" |
Passivated |
CA21038-4-1 |
| QL4C-2G |
.096" – .115" |
Passivated |
CA21038-4-2 |
| QL4C-3G |
.116" – .135" |
Passivated |
CA21038-4-3 |
| QL4C-1G-CAD |
.075" – .095" |
Cadmium Plated, Type II, Class 2 |
CA21038C-4-1 |
| QL4C-2G-CAD |
.096" – .115" |
Cadmium Plated, Type II, Class 2 |
CA21038C-4-2 |
| QL4C-3G-CAD |
.116" – .135" |
Cadmium Plated, Type II, Class 2 |
CA21038C-4-3 |
Complete System Components
| Component | Part Number | Description |
| Stud |
QL4S-EXT Series |
Studs compatible with 1/4-28 two-lead thread receptacles |
| Receptacle |
QL4-21 |
Caged receptacle assembly |
| Retainer |
QL4S-RET Series |
Spring retainers for loose panel applications |
| Grommet |
QL4C-XG / QL4C-XG-CAD |
Load distribution and panel protection (this product) |
Key Features
- Load Distribution: Precision-formed cup design distributes fastener loads across a wider panel area, preventing stress concentration and panel damage
- Panel Protection: Creates protective interface between stud head and panel surface, preventing wear and surface damage
- 304 Stainless Steel: Corrosion-resistant material provides long service life in demanding environments
- Multiple Grip Ranges: Three grip ranges (-1G, -2G, -3G) accommodate panel thicknesses from .075" to .135"
- Two Finish Options: Passivated (QL4C-XG) for general use, cadmium plated (QL4C-XG-CAD) for enhanced corrosion protection
- Industry Standard Interchange: Compatible with CA21038-4 and CA21038C-4 series grommets
📏 Selection Guide: Select grommet dash number (-1G, -2G, or -3G) based on panel thickness to ensure proper fit and load distribution. Choose passivated finish (QL4C-XG) for general aerospace applications or cadmium plated finish (QL4C-XG-CAD) for enhanced corrosion protection in marine, military, and harsh environment installations. Grommets are essential for thin panels, composite materials, and applications requiring optimized load distribution.
Quality & Compliance
Manufactured by Skybolt Aerospace Fasteners under AS9100D certification at our Leesburg, Florida facility (CAGE Code: 435Z0). All QL4C grommets are 100% inspected to drawing specifications and include full material traceability. Material conforms to 304 stainless steel specifications with heat treatment to Condition A. Cadmium plating on QL4C-XG-CAD variants meets AMS QQ-P-416 Type II, Class 2 requirements for aerospace and military applications.
Tridair® is a registered trademark of Howmet Aerospace, Inc. or its subsidiaries. Skybolt products are compatible alternatives and are not manufactured by or affiliated with Howmet Aerospace.
| Qty | Unit Price |
| 1 - 99 | $15.73 |
| 100 - 299 | $13.21 |
| 300 + | $12.42 |
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