Guide bars – faults, solutions, tips
Let’s start with delamination of the face of the guide bar. As a result of poor chain tension or incorrect working technique, the links guiding the chain press against the edges of the groove with great force, creating levers and leading to split ends. If the guide bar has a replaceable nose, it is enough to replace the damaged element, while the standard guides should be replaced with a new one. The same applies to any scratches or cracks.
The second, common defect is blue discoloration on the edges of the guide bar. They appear as a result of overheating when the guide bar links of the chain rub against the walls of the bar. This may be due to nicks, insufficient lubrication or incorrect use.
Another problem is the tapered groove of the guide bar, which is caused when the guide bar gets stuck in the tree during cutting. Point narrowings can be corrected by widening them, but if the groove walls show scratches or cracks, the product should be replaced with a new one.
Chipped or excessively worn edges of the guide bar just behind the star wheel are caused by cutting the wood from below, e.g. during limbing, or too weak chain tension. In this situation, it is recommended to turn the guide bar more often so that the wear is even.
The groove walls of the guide bar may also be bent outwards to form a wedge shape. This is a typical sign of wear. How to extend its use then? Just lay the file flat on the guide bar and file off the burrs and align the sides. In the case of punctate bending, you can try to squeeze the groove walls by using a special insert that is placed in the groove and using a vice to compress the flared walls.
In turn, incorrect sharpening of the chain and, as a result, an uneven cut is the cause of too thin a groove wall or an excessively worn sliding surface. If the groove of the guide bar is too worn, replace the guide bar with a new one, and if the problem recurs, the chain must also be replaced.
The damages presented above are the most common phenomena. Some of them we are able to repair, but most cases will require the purchase of a new guide.
To minimize the risk of failure, follow these four rules:
- When attaching the guide bar, make sure that all screws are properly tightened and that the guide is stationary
- Only use chains with the correct pitch
- Remember to systematically lubricate the chain with professional agents
- Regularly check the chain tension and pay attention to the correct cutting angle and running of the chain in the groove