W/CON.WAS.

W/CON.WAS. refers to a combination fastener in which a screw and a conical washer are pre-assembled as a single unit. It may also be referred to as a screw with conical washer, conical spring washer combination screw, or conical washer SEMS screw.

The conical washer has a conical or dish-shaped cross-section. When compressed by the screw head, it generates axial spring force to help maintain preload at the joint and compensate for slight displacement caused by material settling, thermal expansion and contraction, surface deformation, or equipment operation.

The washer is retained on the screw shank during manufacturing, eliminating the need to separately pick up and install the washer. This helps reduce assembly steps and lowers the risk of missing washers, incorrect orientation, or specification mix-ups.

Product Name: W/CON.WAS. / Screw with Conical Washer / Conical Spring Washer Combination Screw
Assembly Structure: Screw with one conical washer, pre-assembled and retained on the screw shank
Screw Head Types: Pan head, round head, hex head, binding head, or other specified head types
Drive Types: Phillips, slotted, hex socket, Torx, or other specified drive types
Thread Specifications: Metric threads, imperial threads, or other specified thread standards
Thread Types: Machine thread, self-tapping thread, coarse thread, fine thread, or specified thread pitch
Size Range: Can be evaluated and manufactured according to product drawings, physical samples, and actual assembly requirements
Washer Types: Standard conical washer, conical spring washer, serrated conical washer, or other specified structures
Washer Orientation: Can be configured according to screw head type, workpiece contact surface, and load direction
Elasticity Requirements: Can be evaluated according to washer outside diameter, inner diameter, thickness, free height, and compression amount
Assembly Method: Conical washer is retained on the screw shank and is not easily separated during transportation, feeding, or assembly
Screw Materials: Carbon steel, stainless steel, alloy steel, or other specified materials
Conical Washer Materials: Spring steel, stainless steel, carbon steel, or other specified metal materials
Surface Treatments: Zinc plating, nickel plating, black oxide, passivation, or other specified finishes
Strength Grade: Can be evaluated according to product application, drawing specifications, and actual load conditions
Dimensional Precision: Can be manufactured according to thread accuracy, screw length, head dimensions, and washer tolerances
Applicable Standards: Can be evaluated and manufactured according to DIN, ISO, JIS, ANSI, or customer-specified standards
Production Methods: Standard specification supply and customized production based on drawings or samples
Packaging: Bulk packing, bag packing, box packing, tray packing, or customized packaging upon request

The actual screw head type, thread diameter, thread pitch, length, as well as the conical washer inner diameter, outside diameter, thickness, free height, spring force, material, and surface treatment should be confirmed according to the product drawing and actual load conditions.

Pre-Assembled Screw and Conical Washer

The conical washer is installed and retained on the screw during manufacturing, eliminating the need to prepare or position the washer separately during assembly. This helps reduce assembly steps and improve operating efficiency.

Conical Structure Provides Axial Spring Force

When compressed, the conical washer generates an elastic reaction force that creates continuous axial pressure between the screw and the workpiece, helping maintain the fastening condition of the joint.

Actual spring force depends on the washer material, thickness, inner and outside diameters, free height, and compression amount, and should be selected according to actual product load requirements.

Helps Maintain Screw Preload

When the clamping thickness changes due to prolonged loading, material settling, or slight surface deformation, the conical washer can compensate for part of the displacement through elastic deformation, helping reduce rapid loss of preload.

Compensates for Dimensional Changes Caused by Thermal Expansion and Contraction

In equipment exposed to temperature variations, the conical washer can absorb slight displacement caused by thermal expansion and contraction within a certain range, helping maintain pressure at the joint.

Actual compensation capability should still be evaluated according to the temperature range, material coefficient of thermal expansion, and washer compression travel.

Provides Auxiliary Anti-Loosening Performance

The elastic reaction force of the conical washer continuously acts against the screw head, helping maintain pressure at the joint and reducing the possibility of screw loosening under general vibration or dynamic load conditions.

A conical washer is primarily a preload and auxiliary anti-loosening component. For severe vibration, heavy impact, or safety-critical applications, additional locking measures should still be evaluated.

Compact Design with Higher Load Capacity

Conical washers can provide elastic loading within a relatively small axial space, making them suitable for assemblies with limited installation height that still require elastic preload or load compensation.

Reduces Missing Washers and Incorrect Orientation

Because the washer is retained on the screw, it helps reduce missing washers, dropped components, specification mix-ups, or incorrect washer orientation during manual assembly, supporting greater consistency in high-volume production.

Improves High-Volume Assembly Efficiency

Operators only need to handle one complete fastener assembly and do not need to separately pick up the screw and conical washer, helping reduce handling steps and shorten assembly time.

Suitable for Automated Feeding and Fastening

The pre-assembled structure helps reduce problems such as loose washers flipping, overlapping, jamming, or falling off in vibratory bowls, feeding tracks, or automatic fastening equipment, making it suitable for automated assembly processes.

Actual feeding stability should still be tested according to the screw head type, screw length, washer outside diameter, free height, and equipment specifications.

Simplifies Purchasing and Inventory Management

Integrating the screw and conical washer into a single part number can reduce the number of items that need to be managed during purchasing, receiving, material issuing, and production-line preparation, helping lower the risk of shortages or incorrect specification matching.

Customization Based on Drawings and Samples

W/CON.WAS. products can be customized according to customer engineering drawings or physical samples, including screw head type, drive type, thread diameter, thread pitch, length, washer inner and outside diameters, thickness, free height, spring force, installation orientation, materials, tolerances, and surface treatments.

Common Applications

W/CON.WAS. is commonly used in:

  • Machinery and automation equipment
  • Automotive and motorcycle components
  • Motors, fans, and transmission mechanisms
  • Electronic and electrical equipment
  • Enclosures, cabinets, and sheet metal structures
  • Home appliances and consumer products
  • Telecommunications and information equipment
  • Instruments and precision equipment
  • Joints exposed to temperature variations or material settling
  • Assemblies requiring continuous preload or elastic compensation
  • Mass-production and automated fastening lines

Key Considerations When Selecting W/CON.WAS.

Before selection, confirm the screw thread diameter, thread pitch, length, head type, and drive type. The conical washer inner diameter, outside diameter, thickness, free height, spring force, and installation orientation should also be checked against the product design.

Conical washers must operate within an appropriate compression range. If compression is insufficient, the required preload may not be achieved. If the washer is overtightened and remains completely flattened for an extended period, its elastic compensation capability may be reduced, potentially causing permanent deformation or fatigue damage.

The concave and convex orientation of the washer affects the contact position, spring travel, and load behavior. Installation direction should therefore be confirmed according to the product drawing, screw head geometry, and workpiece structure.

For applications involving high temperatures, corrosive environments, high loads, or repeated vibration, the washer material, temperature resistance, fatigue life, surface treatment, and actual load requirements should be further evaluated.

After repeated assembly and disassembly, the conical washer should be inspected for flattening, cracking, warping, wear, or reduced elasticity. If the washer can no longer return to its original conical shape, replacement with a new component is recommended.

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