I went to a store today, and they have EZ lap diamond bits that you can chuck up to a drill motor or Dremel or whatever. $6 or thereabouts, and I'm looking forward to going out tomorrow and attacking the chain saw.
I had a 2 x 4" EZ Lap diamond stone I purchased in 1974, and it sharpened my diving knives beautifully. And those were used for cutting through very heavy ropes that got caught in ships propellers. Finally bit the dust, and was given a new one this Christmas past. $22, what a deal. I've been running around looking for things to sharpen. So, when I saw this EZ lap chainsaw bit, I grabbed it.
Will advise.
Steve