Yes they work most equipment repair shops have simmilar sharpening devices. It is my personal oppinion that
it removes too much of the teeth and shorten the chain life And that learning good filing technique is a better solution.
However it does serve a good purpose If you hit a rock or barbwire it might take quite a filing effort to restore the chain.
The other reason to machine sharpen is faulty hand filing it is good to everynow and then to get back toa correction point
this sharpener will do this . Best used sparingly with file use inbetween machine sharpenings
Sometimes gadgets that look like they are superior to more traditional methods turn out not to be. In my experience, electric chain grinders fit into this category. Like Carpniels says, you can't beat a file in skilled hands. Acquiring the skill is the hard part, but it's worth it.
Eric is dead on here with a minor exception. I bought a file system, and worked with an old chain a bit before I went off on my newer chain. Once I got the basic hang of it, I went at the new chain which was not all that bad, just needed a touch up. I took my time. A lot of time. It probably took me a good hour to sharpen the chain, but when I tried it the results were amazing. The point here is that if you take the time, you can do a good job. I'd bet the point Eric is really making is how good you get how fast. Someone who cuts as much wood has he does can do the sharpening job in less than 5 minutes whereas I take an hour.
The couple times I had my chains done by a pro, they removed so much material, that in 2 shots the chain is worthless.
I have this same machine.
Elk is right on about what he said above.But it is nice to have this on the work bench when you really mess up a chain with a rock. We have lots of rocks around here so I use mine some.
It is adjustable as to how much tooth you grind off.A chain will cut like new when you get done with it.
You will still need to learn to hand file because taking a chain off each time you want to sharpen is to slow.Only use it if you buy one when you mess up your chain bad.........TC
Another problem with electric grinders is they generate so much heat while grinding they don't seem to stay sharp as long afterwards. As others have stated take the time to learn how to hand file correctly and you won't need to buy a grinder or pay to have them sharpened. It will save you money and increase your enjoyment of cutting wood once you master it.
Kind of like building your own fly rod and tying your own flies then catching a fish.
It's all about independence, that's why most people burn wood!