Plain Washers
Washer, a machine component that is used in conjunction with a screw fastener such as a bolt and nut and that usually serves either to keep the screw from loosening or to distribute the load from the nut or bolt head over a larger area. For load distribution, thin flat rings of soft steel are usual.
To prevent loosening, several other types of washers are used. All act as springs to compensate for any increase in the distance between the head of a bolt and the nut, or between the head of a screw and the object being clamped. In addition to the spring action, some of these washers have teeth that bite into the workpiece and the screwhead and provide a locking action. They are called tooth or shakeproof lock washers and have teeth that are bent and twisted out of the plane of the washer face.
The conical washer has spring action, but the only locking action is provided by friction. The helical spring washer is one of the most commonly used lock washers.
Application : A washer is a thin plate (typically disk-shaped, but sometimes square) with a hole (typically in the middle) that is normally used to distribute the load of a threaded fastener, such as a bolt or nut. Other uses are as a spacer, spring (Belleville washer, wave washer), wear pad, preload indicating device, locking device, and to reduce vibration (rubber washer). Washers often have an outer diameter (OD) about twice their inner diameter (ID), but this can vary quite widely.
Washers are usually metal or plastic. High-quality bolted joints require hardened steel washers to prevent the loss of preload due to brinelling after the torque is applied. Washers are also important for preventing galvanic corrosion, particularly by insulating steel screws from aluminium surfaces. They may also be used in rotating applications, as a bearing. A thrust washer is used when a rolling element bearing is not needed either from a cost-performance perspective or due to space restraints. Coatings can be used in an attempt to reduce wear and friction either by hardening their surface, or providing a solid lubricant (i.e. a self-lubricating surface).
The origin of the word is unknown; the first recorded use of the word was in 1346, however, the first time its definition was recorded was in 1611.
Rubber or fiber gaskets used in taps (or faucets, or valves) as seal against water leaks are sometimes referred to colloquially as washers; but, while they may look similar, washers and gaskets are usually designed for different functions and made differently.
Types : Washers are made from a variety of materials, the most popular of which are galvanized carbon steel and stainless steel. Carbon steel is stronger than stainless steel, but stainless steel will not rust or corrode like carbon steel can. Other metal washers include zinc, copper, brass and iron. You can also find specialty washers, such as plastic washers, rubber washers, ceramic washers and phenolic washers.
There are three main types of washers: plain washers, spring washers and lock washers. Within each of these categories are more specialized forms that serve unique purposes.
Tip : Washers (as well as nuts) are sized in both U.S. and metric measurements.
SIZE |
INSIDE DIAMETER |
OUTSIDE DIAMETER |
THICKNESS |
SAE FLAT WASHERS |
|||
#6 |
5/32" |
3/8" |
3/64" |
#8 |
3/16" |
7/16" |
3/64" |
#10 |
7/32" |
1/2" |
3/64" |
1/4 |
9/32" |
5/8" |
1/16" |
5/16 |
11/32" |
11/16" |
1/16" |
3/8 |
13/32" |
13/16" |
1/16" |
7/16 |
15/32" |
59/64" |
1/16" |
1/2 |
17/32" |
1-1/16" |
3/32" |
9/16 |
19/32" |
1-3/16" |
3/32" |
5/8 |
21/32" |
1-5/16" |
3/32" |
3/4 |
13/16" |
1-1/2" |
9/64" |
7/8 |
15/16" |
1-3/4" |
9/64" |
1" |
1-1/16" |
2" |
9/64" |
1-1/8 |
1-3/16" |
2-1/4" |
9/64" |
1-1/4 |
1-5/16" |
2-1/2" |
5/32" |
1-1/2 |
1-7/16" |
3" |
3/16" |
USS FLAT WASHERS |
|||
3/16 |
1/4" |
9/16" |
3/64" |
1/4 |
5/16" |
3/4" |
1/16" |
5/16 |
3/8" |
7/8" |
5/64" |
3/8 |
7/16" |
1" |
5/64" |
7/16 |
1/2" |
1-1/4" |
5/64" |
1/2 |
9/16" |
1-3/8" |
7/64" |
9/16 |
5/8" |
1-1/2" |
7/64" |
5/8 |
11/16" |
1-3/4" |
9/64" |
3/4 |
13/16" |
2" |
5/32" |
7/8 |
15/16" |
2-1/4" |
11/64" |
1" |
1-1/16" |
2-1/2" |
11/64" |
1-1/8 |
1-1/4" |
2-3/4" |
11/64" |
1-1/4 |
1-3/8" |
3" |
11/64" |
1-3/8 |
1-1/2" |
3-1/4" |
3/16" |
1-1/2 |
1-5/8" |
3-1/2" |
3/16" |
1-5/8 |
1-3/4" |
3-3/4" |
3/16" |
1-3/4 |
1-7/8" |
4" |
3/16" |
1-7/8 |
2" |
4-1/4" |
3/16" |
2" |
2-1/8" |
4-1/2" |
3/16" |
2-1/2 |
2-5/8" |
5" |
15/64" |
3" |
3-1/8" |
5-1/2" |
9/32" |
Specification : ~