Types and characteristics of small screws for automotive fasteners

Types and characteristics of small screws for automotive fasteners

In a car, there are about 500 kinds, 4000 fasteners with a total weight of over 50kg. The cost of these fasteners accounts for about 2.5% of the total cost of the vehicle; all fasteners account for about 5% of the number of all parts of the car, and assembly of these fasteners accounts for about 70% of the overall workload of the assembly of the vehicle.

There are many types of small bolts in automotive fasteners, including but not limited to the following:

1. Three-point welded bolts: These bolts are used for fastening automotive parts. Their bearing surface convex welding design makes them suitable for a variety of automotive parts that require strong fixation.

2. U-shape screws: high-strength steel plate card bow sub-card jockey bolts used for large truck undercarriage parts and accessories, providing a stable fastening effect.

3. Chrome-plated license plate screw kit: self-tapping mounting bolts + base nut accessories for automotive modification or repair, providing aesthetic and practical fastening solutions.

4. SUS304 stainless steel hexagon socket cylindrical head hollow exhaust bolts: These bolts are suitable for lamp threading and have a hole design for easy wiring arrangement and fixing.

5. Self-tapping screws: hexagon head bolts, suitable for BMW bumper engine guard installation, providing an efficient fastening effect.

6. Trailer accessory fasteners: super corrosion-resistant trailer hitch fasteners, stabilizers, U-bolt clamps, and anti-sway to ensure stability and safety when driving the trailer.

7. Car modification accessories, such as exhaust bolts and springs, are suitable for various car modification accessories and provide personalized fastening solutions.

8. Magnetic oil drain screws, oil pan oil bolts, and magnet oil plugs: for automotive oil pan fastening with magnetic design for easy maintenance and care1.

9. Micromechanical small screws: 1mm in diameter, suitable for the fastening of small parts such as car key fobs, eyeglass frames, laptop sets, etc.

10. Plum round head self-tapping screws: self-drilling screws with meshes, suitable for customization of non-standard small screws for easy self-tapping installation. These small bolts and screws are widely used in various parts of the car, from daily maintenance to professional modification.

Medium-Strength Metric Class 8.8 Steel Hex Head Screws: These Class 8.8 steel screws are suitable for fastening most machinery and equipment. Dimensions meet ISO (formerly DIN) or DIN specifications. Length is measured from under the head.

Zinc-plated steel screws resist corrosion in wet environments. Black corrosion-resistant-coated steel screws resist chemicals and withstand 1,000 hours of salt spray. To maintain corrosion resistance, use these screws with black ultra-corrosion-resistant-coated nuts and washers.

Match the thread spacing of mating components. Coarse threads are the industry standard; choose these screws if you don't know the pitch. Fine and extra-fine threads are closely spaced to prevent loosening from vibration; the finer the thread, the better the resistance.

Screws that meet SAE J1199 comply with specifications for material standards.

Metric High-Strength Steel Heavy Hex Head Screws for Structural Applications: Designed for construction and exterior building applications, these metric screws are often used to join I-beams and scaffolding. Their partial threading leaves an unthreaded portion substantial enough to stand up to the sideways forces of joints. Made of Class 10.9 steel, these screws are at least 25% stronger than our medium-strength steel heavy hex head screws. They also have a hot-dipped galvanized finish that makes them ten times more corrosion-resistant than zinc plating, so they won't be in wet environments. However, this finish is thicker than others, so it should be used with DIN 6916 structural washers and DIN 6915 structural hex nuts. All meet ISO 7412 (formerly DIN 6914), an international standard for screw dimensions.

High-Strength Metric Class 10.9 Steel Flanged Hex Head Screws: Choose these Class 10.9 steel screws for high-stress applications, such as valves, pumps, motors, and automotive suspension systems. They are at least 25% stronger than medium-strength steel screws. The flange distributes pressure where the screw meets the surface, eliminating the need for a separate washer. Head height includes the flange. Length is measured from under the flange.

Black-phosphate steel screws are mildly corrosion-resistant in dry environments. Zinc yellow-chromate plated steel screws resist corrosion in wet environments.

Screws that meet ISO 898-1 or SAE J1199 comply with specifications and testing requirements for material quality. Screws that meet ASME B18.2.3.9M or DIN 6921 comply with specifications for dimensional standards.

Characteristics of small bolts in automotive fasteners

Small bolts in automotive fasteners have a variety of characteristics and uses, adapting to different assembly needs.

- Hexagonal bolts are the most widely used type of bolts, of which grade A and B bolts are used for critical, high assembly accuracy requirements and bear the enormous shock, vibration, or alternating load occasions. Grade C bolts are used for the rougher surface, and the assembly accuracy requirements for the occasion are not high. The threads on the hexagonal bolts are generally ordinary threads with good self-locking, mainly used for thin-walled parts or occasions subjected to shock, vibration, or alternating loads.

Hexagonal flange bolts: Their head consists of two parts: a hexagonal head and a flange face. The hexagonal head has a larger ratio of support area to stress area, can withstand higher preload, and has better anti-loosening performance, so it is widely used in automobile engines, heavy machinery, and other products.

- Hexagon head bolts with holes and slots: the bolts can be mechanically locked together and are reliable in preventing loosening.

- Hexagonal head screw bolts with holes: cotter pin holes or wire holes are made on the screw, and the bolts can be mechanically relaxed to prevent loosening reliably.

Hexagon head bolts with reamed holes can accurately fix the mutual position of the linked parts and withstand the shear and extrusion generated by transverse force.

Cross-recessed hexagonal head bolts are easy to install and tighten. They are mainly used for light industry and instrumentation with small loads.

Square-head bolts: The square head size is larger, and the stress surface is also larger, so it is easy for the wrench to catch its head or rely on other parts to stop the rotation. They can also be used in parts with T-slots to adjust the bolt position.

Countersunk head bolts are square neck or mortise and tenon bolts with a stop-rotation effect, primarily used in connected parts where the surface is flat or smooth.

- T-slot bolts apply to bolts that can only be connected from one side of the connected parts.

For high-quality, High-Strength Metric Class 10.9 Steel Flanged Hex Head Screws and professional technical support, don't hesitate to contact us at adelajonly@gmail.com or visit our website at https://www.juxinfasteners.com.