TL;DR
A shear pin sprocket is a sacrificial drive component: when a conveyor jams, the shear pin fails so the chain, sprocket, gearbox, and motor do not. When the original sprocket is obsolete and no catalog item matches, the job becomes a sourcing exercise — identify the chain, work through stock options, and spec a custom hub-and-sprocket if nothing stock fits.
What a Shear Pin Sprocket Does
In wastewater and other conveyor service, a jammed chain can transmit enormous torque back into the drive train. A shear pin sprocket breaks that path deliberately: the pin is sized to fail at a set torque, protecting the chain and the drive. It is the cheapest part in the assembly and the one you want to fail.
Step 1: Identify the Chain Being Protected
Everything starts with the chain number. Without it, no sprocket can be specified. Field measurements plus knowledge of what the plant has used historically usually narrow it down — for example, roller chain such as R588 or 78 in municipal water and wastewater service. Confirm the chain number against the actual installation before quoting.
Step 2: Work the Stock Options
Standard shear-pin arrangements from the major catalog manufacturers frequently will not cover a given wastewater application — the chain size, tooth count, or hub configuration is off. When the common catalog brands do not fit:
- Check the engineering-class sprocket lines for a match.
- Look at manufacturers who publish shear-pin arrangements specifically for wastewater and similar applications.
- For low-volume or interim needs, evaluate readily available units — for example, a stainless hub with a nylon sprocket for the chain in question.
Step 3: Spec a Custom Hub and Sprocket
If nothing stock fits, a custom assembly is straightforward to specify. A practical design combines a standard sprocket for the identified chain with stock steel linings and shear pins, mounted on a hub with a sacrificial bearing. One advantage of the design: if the softer bearing wears before the steel, the plant can replace just the bearing and be back in service — the hub and sprocket survive.
A simple sketch is enough to start the conversation; it does not need to be a finished drawing.
What to Send Us
- Chain number (or roller OD, pitch, and roller width).
- Tooth count and sprocket OD.
- Bore size, keyway, and setscrew arrangement.
- Hub dimensions and the existing mounting interface.
- Photos of the failed or worn unit.
The Result
A protected conveyor drive with a known, replaceable sacrificial component — and a sourcing path that does not depend on an obsolete original part.
Need a shear pin sprocket or a custom hub-and-sprocket assembly? RBC Industrial specs and sources shear-pin drive components for wastewater and industrial conveyors. Call (915) 845-8188 or request a quote at rbc-industrial.com.