Frequently Asked Questions (FAQs)
1. What is the difference between a flat washer and a SAE washer?
The main difference between a flat washer and a SAE washer is their outer diameter and thickness. SAE flat washers, created by the Society of Automotive Engineers, have a smaller outer diameter and thinner gauges compared to USS (Unified Thread Standard) flat washers. SAE washers are designed to meet the specific requirements of the automotive industry.
2. What is flat vs spring washers?
Flat washers are flat, while spring washers are curved. Flat washers are commonly used in most applications, while spring washers are recommended for machines and objects that experience vibrations. Spring washers provide an axial load that counters vibrations and prevents fasteners from loosening.
3. Should I use a lock washer and a flat washer?
It is common to use a flat washer under a split locking washer to protect the base material or coating from damage caused by the split washer action. Additionally, a flat washer helps distribute the fastener load and prevents the split washer from falling or grinding into larger clearance hole features.
4. What is the difference between Type A and Type B flat washers?
Type A flat washers are steel washers with broad tolerances, suitable for applications where precision is not critical. On the other hand, Type B flat washers have tighter tolerances and are categorized as Narrow, Regular, or Wide based on their outside diameters. Type B washers are used in applications that require more precise dimensions.
5. Should a flat washer be used with a spring washer?
In cases of relatively large loads and vibration loads, it is recommended to use a combination of flat washers and spring washers. Spring washers are typically not used alone, but in combination with other washers to provide the needed locking and stability.
6. When should flat washers be used?
Flat washers are primarily used to increase the bearing surface area of a screw and reduce the surface pressure applied to the fastened object. They help prevent the sinking of the bearing surface under pressure, thus reducing the risk of loosening. Flat washers are particularly effective in reducing surface pressure.
7. When should you use spring washers?
Spring washers, also known as split lock or split ring washers, are used when there is a need to prevent fasteners from loosening due to vibration. They provide a locking effect and help keep the fasteners secure in applications where vibrations are present.
8. When should you not use a lock washer?
Lock washers, like wedge-locking washers, should not be used against soft surfaces such as wood or soft plastic. These soft materials may not be able to hold the serrations of the washer, leading to rotation of the bolt and a compromised bolted joint.
9. Where is the best place to put a lock washer?
A lock washer should be placed under the threaded fastener, either under a nut or the head of a screw or bolt. In assemblies with a nut and bolt, the lock washer should be positioned between the nut and the head of the bolt. This allows for proper tightening of the threaded fastener.
