Captive Panel Retainers are designed to offer a retaining option for captive panel screws. They are most commonly used in sheet metal products where a threaded hole cannot be manufactured into the panel.
When access is needed, unthreading the screw allows for access, while the retainer keeps the screw attached. Selecting a captive panel retainer type is the perfect solution to prevent a lost screw from becoming lost during a field repair or creating a safety hazard.
Step 1 - Types of Captive Panel Retainers
There are several types of captive panel retainers that depend on the other components used in your products and the different installation methods available, such as using springs or non-threaded retainers. There are captive panel retainer types A through G and these products are categorized based on three features:
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The Installation Method
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Retaining Style
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Spring Tensioned or Not
The retainer types for captive panel screws are as follows:
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Installation Method: Knurled - Press Fit
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Retaining Style: Threaded Retainer
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Spring Tensioned: No
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Installation Method: Flare Style
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Retaining Style: Threaded Retainer
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Spring Tensioned: No
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Installation Method: Flare Style
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Retaining Style: Non-Threaded - Retaining Ring Required
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Spring Tensioned: No
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Installation Method: Flare Style
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Retaining Style: Threaded Retainer
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Spring Tensioned: Yes, Spring Required
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Installation Method: Flare Style
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Retaining Style: Non-Threaded - Retaining Ring Required
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Spring Tensioned: Yes, Spring Required
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Installation Method: Flare Style
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Retaining Style: Threaded Retainer
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Spring Tensioned: No
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Installation Method: Flare Style
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Retaining Style: Threaded Retainer
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Spring Tensioned: No
Step 2 - Retainer Material
The type of material selected has a direct effect on its strength, corrosion resistance, and cost.
Steel
choosing steel will be less costly, but won't be resistant to corrosion, is magnetic, and of average weight.
Stainless Steel
choosing stainless steel will be more costly, but is resistant to corrosion, though is non-magnetic and of average weight.
Brass
choosing brass is more costly, is highly corrosion-resistant, though non-magnetic, and is heavier in weight.
Step 3 - Thread Type for Captive Screws Compatibility
Lyn-Tron offers these products in a wide variety of common thread sizes in both inches and metric if threaded screws are used.
Inch
| Thread Type | Available in Type’s |
|---|---|
| 4-40 | A-F |
| 6-32 | A-G |
| 8-32 | A-G |
| 10-24 | A-F |
| 10-32 | A-G |
| 12-24 | B-G |
| 1/4-20 | A-G |
| 1/4-28 | A-F |
| 5/16-18 | A |
| 5/16-24 | F |
| 3/8-16 | A |
Metric
| Thread Type | Available in Type’s |
|---|---|
| M3x0.5 | A-E |
| M3.5x0.6 | A-E |
| M4x0.7 | A-E |
| M5x0.8 | A-E |
| M6x1 | A-E |
Step 4 - Shank Length
The overall length of a retainer is the same for each thread type. There is the option of choosing different shank lengths to match the thickness of common materials. Press Fit style inserts should be either the same thickness or slightly shorter than what is being installed into for a flush fit. Flare style retainers will be slightly longer than the thickness to allow for flaring or swaging the end.
Inch
| Retainer Type | Shank Lengths available |
|---|---|
| Type A | 0.050, 0.080, 0.125, 0.188, 0.250 |
| Type B, C, D,E, and F | 0.062, 0.093, 0.125, 0.187, 0.250 |
| Type G | 0.165, 0.230, 0.290 |
Metric
| Retainer Type | Shank Lengths Available |
|---|---|
| Type A | 1.3, 2, 3.2, 4.8, 6.4 |
| Type B, C, D, and E | 1.6, 2.4, 3.2, 4.8, 6.4 |
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