I'm a firefighter by trade, and we use carbide-tipped chains on our vent saws...they are NOT indestructible, but offer significantly longer cutting in really bad crap (tar, nails, light metal sheeting, screws, etc). We never have time to sharpen on a fire, and won't sharpen a carbide chain as this is specialty work. A carbide chain
may offer you a little longer life in the clay and rock you're using your saw in, but why would you want to do this to the rest of your saw?
For ultra precise sharpening, MUCH MUCH MUCH quicker, far less damaging than any grinder, and WAY cheaper, I use a Timberline Sharpener.
Timberline Chainsaw Sharpener |Sharpen Your Chainsaw Watch the online videos. I did, bought one immediately, and have THROWN AWAY all my hand filing devices, files, holders, angle keepers...just watch the videos, buy the beautiful thing, and never look back. I was so impressed after using mine the first time that I promise I would have paid three times as much as I actually did for it. I cannot recommend the Timberline Sharpener highly enough! After you buy yours, you will kick yourself for having not purchased it a year ago when you first saw it, and you'll be buying it for your family and friends too. Really.
When I buy chains, I buy from Madsen's saw shop:
Welcome To Madsen's Online This is a fantastic, old-school, talk-to-the-actual-mechanic-in-back type of place. You can't order online from them. Instead, call them. Novel idea, right? Awesome knowledge base on their site and in their shop, plus when you buy one loop of chain they send you two. I won't even look anywhere else again.