How to properly sharpen a saw chain in harvester head ?
Let’s start with the obvious, i.e. that proper sharpening of the chain has a decisive influence on the quality and efficiency of work. So how to do it properly and professionally?
There are 5 main factors:
- File – preferably use one with a diameter of Ø 5.5 mm (7/32 inch), remember to keep the handle at an angle of 10 degrees down
- Inclination angle of the top plate – it is important to maintain a similar angle of inclination for all chain links. In addition, we should remember about the correct direction of sawing, i.e. from the inside of the teeth to the outside.
- Angle of the side plate – this parameter is influenced by the size of the file and the place of sawing the side plate
- Cutting angle – the right angle will be created automatically when the top and side plates have the right slope
- Depth gauge depth – Be sure to check the depth gauge after sharpening all cutters. When sharpening for the first time, the depth gauge should be a maximum of 1.2 millimeters (0.05 inch) and the front edge of the depth gauge should also be rounded.
- If the file is held too high, the cutting angle becomes negative and the links become blunt (eg too large a cutting angle). Such a chain requires more power, which causes the side links to wear out faster. In addition, the back surfaces of the links (at the guide) are subject to accelerated wear (see item 1).
- If you hold the file too low, the cutting angle will be positive and the link sharp. This can cause the chain to clatter, weaken it and increase the risk of slamming. In addition, the side links as well as the edges of the teeth will be exposed to accelerated wear (see item 2).
- If the cutting teeth are damaged, e.g. as a result of hitting a stone, when sharpening and sawing the chain, pay special attention to the most damaged link. Based on this element, dimension “a” should be determined so that the quality of the cut is uniform. Otherwise, the cut will be irregular and at an angle. If the length of dimension “a” is 3-4 mm (0.1-0.2 inch), the chain should be taken out of service (see item 3).