Shear Bolts

Pattern Fasteners manufactures special and bespoke shear bolts for mechanical assemblies where controlled shear behaviour or resistance to transverse loading is an important part of the component design.

Unlike an ordinary fastening application, where a bolt is primarily intended to generate clamping force, a shear bolt may be designed so that its shank carries lateral loading or fails at a predetermined load to protect other parts of an assembly.

What Is a Shear Bolt?

Shear forces act across the bolt rather than along its axis.

Depending on the application, a shear bolt may therefore be designed either to:

• Withstand a specified transverse load, or

• Fail in a controlled manner when a predetermined load is exceeded

In mechanical joints subjected to shear, the design and position of the plain shank can be particularly important because threads within the shear plane can influence joint performance.

Custom Shear Bolts

Because shear requirements vary considerably between assemblies, shear bolts are often application-specific.

Pattern Fasteners can manufacture bolts with:

• Controlled shank diameters

• Plain shear sections

• Reduced or necked sections

• Specific thread lengths

• Special head forms

• Cross holes

• Grooves or machined break points

• Special material requirements

• Customer-defined tolerances

Shear Pins & Sacrificial Fasteners

Some shear bolts are intentionally used as a mechanical protection device.

If an assembly becomes overloaded, the fastener is designed to shear before more expensive components such as shafts, gearboxes or machinery are damaged.

For these applications, the bolt geometry and material specification form an important part of the overall system design and should be determined by the equipment designer.

Shear Bolts Made to Drawing

We can manufacture replacement and bespoke shear bolts from an engineering drawing, specification or existing sample.

For safety-critical applications, the required material, mechanical properties and dimensional tolerances should be clearly defined by the customer.