Once a sprocket has worn, it can cause rapid chain wear and will need to be replaced at the first available opportunity. Replace it too early, however, and you could be incurring unnecessary costs.
Examining a sprocket
If you examine the faces of the sprocket teeth you should be able to tell immediately whether a sprocket has worn or not.
What you are looking for is a shiny strip on each of the teeth, about the pitch circle diameter, as indicated in the illustration below:
It is worth noting though that a high-quality sprocket is likely to have seen several chains before it shows anything like the extent of wear shown above.
Alignment
Misaligned sprockets are a common cause of premature chain wear, so when sprockets are replaced it is important that they are properly aligned with the shafts.
Once the shafts and sprocket tooth faces are accurately aligned, the load will be distributed evenly across the entire chain width which will help to achieve optimum service life.
To check for wobble, a straight edge, nylon line or laser sight tool should be used across the machined faces of the sprockets in several positions. You can then drive the keys home as a final check.
Hardened teeth
Sprocket tooth wear can also occur when low grades of sprocket material have been used, or when using small sprockets with a speed ratio greater than 4:1.
It is recommended to manufacture the sprockets with hardened teeth to overcome some of the issues associated with escalating tooth wear.
FB Chain has the engineering capability to offer sprockets in materials to suit the application conditions, such as special grade alloy steels.
Split sprockets
Another FB Chain speciality is our ability to manufacture high-quality sprocket segments. Split sprocket solutions can save large amounts of downtime when it comes to replacing large, difficult-to-access drives.