What is the function of a taper washer?

To provide a parallel surface for the nut and bolt head on a non-parallel (tapered) surface, like the flange of an I-beam, ensuring uniform load distribution and preventing bolt bending.

What is the standard taper for washers used on I-beams?

The standard taper is 1 in 6 (Clause 2.1 and Fig. 1).

How is a taper washer for a 20 mm bolt designated?

As 'Taper Washer 20 IS 5374' for a square type, or 'Channel Washer 20 IS 5374' for a channel type (Clause 5).

What material is specified for taper washers?

Mild steel conforming to IS 226 (now superseded by IS 2062) (Clause 3.1).

IS 5374

: 1990

Taper washers for I-beams

CurrentSpecializedSpecificationBIMStructural Engineering · Fasteners, Bolts and Anchors

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This standard specifies the material, dimensions, finish, and designation requirements for steel taper washers. These washers are specifically designed to provide a flat bearing surface for bolt heads and nuts when fastening components to the sloped flanges of I-beams and channel sections.

Specifies dimensions and other requirements for taper washers for use with I-beams.

Quick Reference Values

Taper for square washers1:6

Hardness range (HV)140 to 250

Material specificationMild steel as per IS 2062

Taper for channel washers98 degrees (angle)

Practical Notes

Essential for achieving correct bolt pretension and preventing localized bending in the bolt when connecting to tapered flanges of structural sections like ISMB, ISMC etc.

There are two distinct types specified: square washers for I-beams (with a 1:6 taper) and wedged washers for channels. Ensure the correct type is used for the corresponding structural section.

Though the code references the withdrawn IS 226, use steel conforming to IS 2062 for material.