4x20x12 blind rivets AN 381 Al/St large head 20 pcs.
Rivets AN 381 Al/St with large flat head. Size d × l × dk: 4 × 20 × 12 mm. Aluminium body, steel mandrel with white electro-zinc plating. Grip range: 14,5–16,5 mm; hole 4,1 mm. Pack of 20 pieces.

Rivets AN 381 with large head — 4 × 20 × 12 mm, Al/St, 20 pieces
Open-end rivets with a break mandrel for joining components with installation access from one side. The body is made of aluminium alloy Al and the mandrel of steel St with white electro-zinc plating. The large flat head has a diameter of 12 mm. AN 381 is the catalogue designation of this family.
Key specifications
- Standard: AN 381
- Rivet type: Open-end with break mandrel
- Head type: Large flat
- Body diameter d: 4 mm
- Body length l: 20 mm (nominal)
- Head diameter dk: 12 mm
- Head height k: max. 2,5 mm
- Mandrel diameter dm: 2,1 mm
- Minimum mandrel length p: 25 mm
- Grip range: 14,5–16,5 mm
- Hole diameter: 4,1 mm
- Body material: Aluminium alloy Al
- Mandrel material: Steel St
- Mandrel coating: White electro-zinc plating

Selection and installation
Size 4 × 20 × 12 mm indicates, in order, body diameter d, nominal body length l beneath the head and head diameter dk. The recommended grip range is 14,5–16,5 mm. The recommended hole diameter is 4,1 mm. The minimum mandrel length p is 25 mm. The manufacturer recommends trials to select the setting parameters.

Scope of delivery and weight
Sales unit: one pack of 20 rivets AN 381 Al/St 4 × 20 × 12 mm. The price is for the entire pack.
Previously assigned weight for the sales quantity of 20 pieces: 0,15 kg. The value has been retained without recalculating the weight of the smaller pack.
The images show the product family and an illustrative pack; they do not document the exact number of pieces or the actual delivery carton. Dimensions and quantity are specified in the technical table. The in-house diagram is a catalogue illustration, not production documentation.
Frequently asked questions
How many rivets does the price cover?
The price is for one pack of 20 pieces.
What does the size 4 × 20 × 12 mm mean?
The body diameter is 4 mm, the nominal length beneath the head is 20 mm, and the large head diameter is 12 mm.
For what thickness of joined components should this rivet be selected?
The recommended grip range is 14,5–16,5 mm. The recommended hole diameter is 4,1 mm. Setting parameters should be selected through trials.
What is the rivet made of?
The body is made of aluminium alloy Al, and the steel St mandrel has white electro-zinc plating.
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ConditionNew
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StandardAN 381
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Sales unitpack
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Source referenceKAT47922_n
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Quantity per pack20 pcs
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Pack mass0,15 kg
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Rivet typeOpen-end with break mandrel
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Head typeLarge flat
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Body diameter d4 mm
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Body length l20 mm (nominal)
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Head diameter dk12 mm
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Head height kmax. 2,5 mm
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Stud diameter dm2,1 mm
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Minimum stud length p25 mm
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Joining range14,5–16,5 mm
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Bore diameter4,1 mm
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Body materialAluminium alloy Al
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Stud materialSteel St
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Stud coatingWhite electroplated zinc
1. Eye protection:
– Always wear safety goggles or a face shield to protect your eyes from sparks, particles and metal fragments.
2. Hearing protection:
– When working in a noisy environment, use ear defenders or earplugs to prevent hearing damage.
3. Respiratory protection:
– When working in dusty surroundings or in the presence of fumes, wear a filtering mask or an appropriate respirator.
– Ensure proper ventilation of the workstation.
4. Hand and skin safety:
– Use protective gloves that protect against mechanical injuries and chemicals.
– Where necessary, use protective creams to prevent irritation and dry skin.
5. Work clothing:
– Work in protective clothing resistant to sparks and splashes.
– Avoid loose clothing, jewellery and loose hair near machinery.
6. Fire risk:
– Keep the workstation free of flammable materials (e.g. paper, fabrics and chemicals).
– Keep a serviceable fire extinguisher close at hand and know how to use it.
7. Electrical hazards:
– Check the condition of cables and electrical equipment before use.
– Do not use electrical devices in damp conditions.
– Disconnect equipment from the power supply during maintenance or repairs.
8. Use of machinery and tools:
– Regularly inspect the technical condition of machines and tools.
– Use equipment in accordance with the manufacturer's instructions.
– Blades and tools should be maintained regularly and kept in good condition.
– Machines should be fitted with appropriate guards and protective devices.
9. Handling materials:
– Use handling equipment to move heavy components.
– Lift and carry using ergonomic practices to avoid injury.
10. Working with chemicals:
– Store chemicals in labelled, safe containers.
– Use substances in accordance with the manufacturer's instructions and occupational health and safety rules.
– Ensure air circulation when using chemicals.
Other important rules:
– Keep the workstation clean and tidy.
– Ensure adequate lighting in the working area.
– Provide occupational health and safety training.
– Carry out regular safety audits and comply with current regulations.

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