Spring Lock Washers (DIN 127 / ASME B18.21.1)
Spring lock washers, including Split Lock Washers and Helical Spring Lock Washers, are crucial components in preventing bolts and nuts from loosening due to vibrations. These washers are designed to provide a positive locking effect by exerting continuous axial force, ensuring that fasteners remain tightly secured. The Helical design helps to maintain preload, which is essential for the reliability of bolted connections in high-vibration or dynamic load conditions. Whether used in automotive, industrial machinery, or infrastructure projects, spring lock washers provide consistent performance and ensure the integrity of critical assemblies.
- Prevent loosening under vibration
- Retain preload in dynamic conditions
- Available in Split, Helical, Hi-Collar types
- Durable stainless steel construction
- Corrosion-resistant materials (304/316)
- Conform to DIN 127, ASME B18.21.1 standards
Technical Specifications
Product Name
Spring Lock Washers / Split Lock Washers / Helical Spring Lock Washers
Standards
DIN 127 (Type A, Type B), ASME B18.21.1, ISO 7089, JIS B 1251
Material
Stainless Steel 304 (A2), Stainless Steel 316 (A4), Silicon Bronze, Spring Steel (65Mn), Phosphor Bronze
Grades / Hardness
Hardened spring steel, HRC 40-45
Diameter Range
M3 to M50 (metric), 1/8″ to 2″ (imperial)
Surface Finish
Phosphated, Black Oxide, Zinc Plated, Mechanical Galvanized
Certifications
1: Vibration-induced loosening
What happens: Vibrations from machinery, vehicles, or structures can cause fasteners to lose preload and eventually become loose.
Washer solution: Spring lock washers provide consistent axial force that keeps fasteners tight, even under continuous vibration. The helical shape of these washers ensures constant pressure and helps prevent loosening, especially in high-vibration environments like automotive, aerospace, and industrial machinery.
2: Loss of preload under fluctuating loads
What happens: In dynamic applications, bolts and nuts lose their preload over time, reducing their effectiveness.
Washer solution: Helical spring lock washers maintain preload by applying continuous force to the joint, thus ensuring reliable performance over time. Split lock washers and high-collar washers also help by creating a locking mechanism that prevents loosening and ensures secure assemblies.
3: Limited space for lock washers
What happens: In applications with space constraints, a traditional washer might not fit.
Washer solution: Hi-Collar Lock Washers (DIN 7980) provide a high-performance solution in confined spaces, offering both a locking effect and vibration resistance without taking up excessive space.
4: Corrosion in harsh environments
What happens: In corrosive environments, such as marine or chemical processing, standard washers may corrode quickly.
Washer solution: Stainless steel (304, 316) and phosphor bronze spring lock washers offer exceptional corrosion resistance, making them ideal for industries requiring durability in challenging environments.
A) DIN 127 (Type A / Split Lock Washers) — example
| Nominal d (for bolt) | Washer ID (d1) | Washer OD (d2) | Thickness (s) |
|---|---|---|---|
| M6 | 6.4 | 12 | 1.6 |
| M8 | 8.4 | 16 | 1.6 |
| M10 | 10.5 | 20 | 2.0 |
| M12 | 13.0 | 24 | 2.5 |
| M16 | 17.0 | 30 | 3.0 |
B) ASME B18.21.1 (Heavy Duty Split Lock Washers) — example
| Nominal d (for bolt) | Washer ID (d1) | Washer OD (d2) | Thickness (s) |
|---|---|---|---|
| 1/4″ | 0.281 | 0.625 | 0.031 |
| 5/16″ | 0.344 | 0.750 | 0.031 |
| 3/8″ | 0.406 | 0.875 | 0.031 |
| 1/2″ | 0.500 | 1.000 | 0.035 |
| 5/8″ | 0.625 | 1.125 | 0.040 |
C) Hi-Collar Lock Washers (DIN 7980)
Designed for use with socket head cap screws, providing an ideal locking solution for confined spaces.
Torque, preload, and friction control
Tighten bolts with the specified torque values to ensure proper washer compression. Spring lock washers are designed to provide axial force that keeps fasteners under constant preload, which helps retain joint integrity under dynamic loads.
Ensure the washer is not over-compressed, as this could damage its functionality.
Washer material compatibility
For marine and offshore applications, use stainless steel or phosphor bronze washers to prevent corrosion.
For heavy-duty applications, such as construction or automotive industries, choose high-collar washers (DIN 7980) for a secure lock in limited spaces.
Installation tips
Ensure the washer’s ID matches the bolt diameter and that the washer is placed under the nut or bolt to avoid direct contact with softer substrates.
Use high-collar washers when space is limited, and consider split lock washers for general locking in vibration-prone environments.
Corrosion prevention
For outdoor or corrosive environments, consider mechanically galvanized or zinc-plated spring lock washers. When using phosphor bronze or silicon bronze washers, ensure they are properly selected for electrical or marine use.
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FAQ
What is the difference between spring lock washers and split lock washers?
Spring lock washers exert axial force to retain preload, while split lock washers are designed to prevent loosening by using a split ring that locks into place.
When should I use a Hi-Collar spring lock washer?
Hi-Collar lock washers (DIN 7980) are used in situations where the space is limited, such as with socket head cap screws, providing vibration resistance in confined areas.
Are stainless steel spring lock washers suitable for outdoor use?
Yes, stainless steel spring lock washers (304/316) are corrosion-resistant and ideal for outdoor, marine, and chemical environments where durability is essential.
How do spring lock washers prevent loosening?
Spring lock washers maintain preload on fasteners by applying continuous axial force, ensuring that joints stay secure even in high-vibration conditions.
Can spring lock washers be used in heavy-duty applications?
Yes, heavy-duty spring lock washers (ASME B18.21.1) are designed for high-torque and high-vibration environments, such as automotive and construction industries.