Originally Posted by Eleganza
If your dealer doesn't handsharpen the chain then you have no chance of handsharpening it after. The heat of a sharpening stone will temper the metal and make it too hard to sharpen with a file.
This is incorrect, what actually happens when a chain is sharpened by a grinder is that the steel loses its temper and it becomes softer.
Metal is tempered is if its quenched in oil or water while its red hot.
If you see a tooth that has turned blue its likely to have been annealed by heating and then slow cooling.
If you use a grinder to sharpen a chain it shouldn't throw sparks if it does too much pressure is being applied.
Different chains are harder than others, Stihl chains are harder to sharpen than Oregon, Carlton or Windsor.
That said a good sharp file is still the best way to get a sharp chain and keep the temper of the teeth.
The cutters need to be the same length or the chain will cut crooked.
If you hit a stone or nail/wire make sure all the cutters are sharpened to the same length not just the damaged ones.
If the bar groove is worn and the chain can rock side to side more than 1-2mm it can also cause crooked cutting.
When you file file forward and every three strokes tap the tip of the file on a hard surface like the vise, this clears the swarf from the file and lets it cut cleanly.
A handy tool is the Husky roller file guide
, it has a depth gauge built in for the rakers.
My preference is to sharpen 4-5 chains at home in the vice with the sharpener that clamps to the bar and has a fixed angle.
Bring them all with you and change them during the day rather than touching them up during cutting.