Fasteners Specification / BS Fasteners / ISO Fasteners / DIN Specification / Flat Washer Standards | Check Price
A washer is a thin plate (typically disk-shaped) with a hole (typically in the middle) that is normally used to distribute the load of a threaded fastener, such as a screw 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 usually have an outer diameter (OD) about twice the width of their inner diameter (ID).
Washers are usually metal or plastic. High quality bolted joints require hardened steel washers to prevent the loss of pre-load due to Brinelling after the torque is applied.
Rubber or fiber gaskets used in taps (or faucets, or valves) to stop the flow of water 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.
Washers are also important for preventing galvanic corrosion, particularly by insulating steel screws from aluminium surfaces.
Washers can be categorised into three types;
Plain washers, which spread a load, and prevent damage to the surface being fixed, or provide some sort of insulation such as electrical
Spring washers, which have axial flexibility and are used to prevent fastening loosening due to vibrations
Locking washers, which prevent fastening loosening by preventing unscrewing rotation of the fastening device; locking washers are usually also spring washers.
The American National Standards Institute (ANSI) provides standards for general use flat washers. Type A is a series of steel washers with broad tolerances, where precision is NOT critical. Type B is a series of flat washers with tighter tolerances where outside diameters are categorized as 'Narrow', 'Regular' or 'Wide' for specific bolt sizes.
'Type' is not to be confused with 'form' (but often is). The British Standard for Metric Series Metal Washers (BS4320) written in 1968 coined the term 'form'. The forms go from A to D for Bright Metal and denote outside diameter and thickness. They can be summarised as -
Form A: Normal diameter, normal thickness
Form B: Normal diameter, light thickness
Form C: Large diameter, normal thickness
Form D: Large diameter, light thickness
Forms E to G relate to black metal washers.
Fender washers, Stainless steel 18-8
Washer size (Diameter) is the size bolt that the washer is used with. Thus a 1/4 washer fits a 1/4 bolt.
| Nominal screw sizes M (mm) |
Screw pitch thread P (mm) |
Internal (Inside) diameter hole d1 (mm) |
External (Outside) diameter d2 (mm) |
thickness H (mm) |
||
|---|---|---|---|---|---|---|
| 1st choice |
2nd choice |
Coarse | Fine | |||
| 1 | 0.25 | 1.1 | 3 | 0.3 | ||
| 1.2 | 0.25 | 1.3 | 3.5 | 0.3 | ||
| 1.4 | 0.3 | 1.5 | 4 | 0.3 | ||
| 1.6 | 0.35 | 1.7 | 4 | 0.3 | ||
| 1.7 | 1.8 | 4.5 | 0.3 | |||
| 1.8 | 0.35 | |||||
| 2 | 0.4 | 2.2 | 5 | 0.3 | ||
| 2.5 | 0.45 | 2.7 | 6 | 0.5 | ||
| 2.6 | 2.8 | 7 | 0.5 | |||
| 3 | 0.5 | 3.2 | 7 | 0.5 | ||
| 3.5 | 0.6 | 3.7 | 8 | 0.5 | ||
| 4 | 0.7 | 4.3 | 9 | 0.8 | ||
| 5 | 0.8 | 5.3 | 10 | 1 | ||
| 6 | 1 | 0.75 | 6.4 | 12 | 1.6 | |
| 7 | 1 | 7.4 | 14 | 1.6 | ||
| 8 | 1.25 | 1 | 8.4 | 16 | 1.6 | |
| 10 | 1.5 | 1.25 or 1 | 10.5 | 20 | 2 | |
| 12 | 1.75 | 1.5 or 1.25 | 13 | 24 | 2.5 | |
| 14 | 2 | 1.5 | 15 | 28 | 2.5 | |
| 16 | 2 | 1.5 | 17 | 30 | 3 | |
| 18 | 2.5 | 2 or 1.5 | 19 | 34 | 3 | |
| 20 | 2.5 | 2 or 1.5 | 21 | 37 | 3 | |
| 22 | 2.5 | 2 or 1.5 | 23 | 39 | 3 | |
| 24 | 3 | 2 | 25 | 44 | 4 | |
| 27 | 3 | 2 | 28 | 50 | 4 | |
| 30 | 3.5 | 2 | 31 | 56 | 4 | |
| 33 | 3.5 | 2 | 34 | 60 | 5 | |
| 36 | 4 | 3 | 37 | 66 | 5 | |
| 39 | 4 | 3 | 40 | 72 | 6 | |
| 42 | 4.5 | 3 | 43 | 78 | 7 | |
| 45 | 4.5 | 3 | 46 | 85 | 7 | |
| 48 | 5 | 3 | 50 | 92 | 8 | |
| 52 | 5 | 4 | 54 | 98 | 8 | |
| 56 | 5.5 | 4 | 58 | 105 | 9 | |
| 60 | 5.5 | 4 | 62 | 110 | 9 | |
| 64 | 6 | 4 | 66 | 115 | 9 | |
| 68 | 70 | 120 | 10 | |||
| 72 | 74 | 125 | 10 | |||
| 76 | 78 | 135 | 10 | |||
| 80 | 82 | 140 | 12 | |||
| 85 | 87 | 145 | 12 | |||
| 90 | 93 | 160 | 12 | |||
| 100 | 104 | 175 | 14 | |||
Types of Washer | |||||
Fender Washer Application Industries
Sunflex Metal Industries are engaged in manufacturing of robust quality of Fender Washer. These Fender Washer are widely used in the following industries:
Mining Industries Transport Industries- Rail and Road Construction Industries / Building Systems Manufacturing Industries Agriculture Industries Energy Industries Water Industries Automotive Industries Ship Building Industries Nuclear Power Plant Paper & Pulp Industries Sugar Industries Engineering Cement Industries Petro-Chemical Industries Food Industries Oil & Gas Industries Chemical & Pharmaceutical Industries
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