If you're looking for a chainsaw sharpener read on to find out more about chainsaw sharpening and how you can get the best deal online.
A chainsaw is a useful and powerful piece of equipment. But once a chain blade becomes blunt you're wasting your time, damaging your equipment and putting yourself at risk. A sharp chain will self feed, that is it needs little or no pressure to cut but the chain blade draws itself into the wood. A sharp chain will produce square chips. If your making something more like sawdust then it's a sign you need to use a chainsaw sharpener or take your saw for sharpening. You should stop working with your chain saw as soon as you realize the chain is dull. Forcing a blunt saw to cut puts unnecessary strain on the motor, chain, sprocket and guide bar. Put simply your chain saw was not designed to work like this and such abuse will result in breakdowns and shorten the life of your saw. If you keep working with a blunt saw you'll get tired more easily and the job becomes much tougher leading to frustration and impaired judgment. Accidents and injuries are more likely. This is another good reason to stop when your saw gets dull.
The simplest chainsaw sharpeners are basically guides for files which hold the file at the correct angle and position to sharpen each cutter. Some chainsaw users will sharpen freehand using just a file but without some sort of guide it's tricky to hold the file in the right way consistently. A quick free-hand touch up to keep the saw working is OK but the chain will need some extra work to correct the cutting angles or some time with a professional sharpener to regain it's full cutting performance.
After a few sharpeners you may find the chain does not cut so well. The cutters may be sharp but do not cut into the wood effectively. If this happens then the depth gauges need adjusting. As you sharpen the saw chain metal is filed or ground off the cutters and they get lower and lower. Each cutter is behind a depth gauge which determines how much of a "bite" it takes out of the wood. This "bite" is the height difference between depth gauge and cutter. Every 2-3 times you sharpen you should check and adjust the depth gauge height. A few models of sharpeners will incorporate some means of grinding the depth gauges, others need a separate tool.
Electric sharpeners come in a few varieties. The best ones allow you to clamp the chain while a grinding wheel is applied to do the job of sharpening. This method is faster and easier than filing and produces good results. The better ones make short work of lowering the depth gauges to match the cutters.