At least while it was wet yesterday I got to try out the electric chain sharpener and made a few notes for any of you contemplating going down this route.
Hand File
For comparison purposes, I first sharpened a single tooth with a hand file. I generally use Stihl chains that have that nice crisp 30 degree witness line on the top of each tooth. This happened to be an Oregon, without any line to follow, so I had to pay attention to the angle marker on the file guide instead.
Granberg 12V sharpener
Didn't start too promising. I had watched a few videos so I thought I knew how to set it up, however, try as I may, I couldn't get the little cylindrical grinding stone to wind down low enough, it hovered just above the teeth, unable to cut anything except fresh air ! Had a look on their website, the FAQ revealed nothing, so I had a closer look again. When I flipped up the top hinged part I could see where it was catching. A couple of gentle strokes with a file on each side and it worked perfectly.
After a bit of playing around to get the hang of it I set to on a chain. This is how it looked after my first pass.
It needed just a little bit more taking off, but that is dead easy to do by just turning the adjustment screws. Once set up the jig is a lot quicker than hand filing and doesn't require any effort to get every tooth consistent.
Getting the leading depth gauges down to the correct height for the chain to cut chips instead of making sawdust was easy too. The jig comes with 3 different diameter grinding stones, though it doesn't matter which one is used on the depth guages, so I used a bigger one to save wear on the one needed for my 3/8 pico chains.
I used a few drops of cutting oil on the tiny grinding stone to help it to cut smoother and run cool. When the time comes to buy a replacement stone I will probably pay the extra and get the diamond coated ones that should last a very long time and without the diameter reducing, which is bound to happen with the gritstones.