Curved Washers

Also known as saddle or crescent washers, these shaped washers are also made from Spring Steel and is defined by the DIN137 Form A standard. When compressed by tightening the nut, the DIN 137 curved washer exerts a spring force between the tightened bolt and the fastening substrate creating frictional resistance to rotation.

Application

When the washer is loaded it deflects, acting like a spring, and can provide a preload between two surfaces. It is used typically in applications where assemblies need a part to take up play and eliminate rattle, or maintain assembly tension and compensate for expansion or absorb intermittent shock loads. Because of their shape and ability to fit around surfaces such as tubes and pipe, they are used frequently in piping installations, although the functional properties of Spring Steel are wasted in this instance and mild steel would work just as well. Again, because they are designed for bolted connection they come in complementary bolt sizes. We manufacture from M8 to M36.

Curved washers exert a relatively light thrust load, and are for first 75% of their deflection the loads and travel are relatively predicable from the modelling equations, but beyond 75% as it reaches full compression, the spring rate will become non-linear and un-predictable rapidly.

Base Materials

We default to SAE1075 Carbon Steel for our standard production which we harden to Rockwell C of between 40-45, and then double temper. However we also manufacture these curved washers from both wear resistant and corrosion resistant materials, NM400 & NM500,as well as Stainless Steel AISI301 / X12 CrNi 17-7 as well as AISI 316 / X5 CrNiMo 17-2.

Dimensions and available sizes are listed along with our other solutions for Bolted Connections.