Now, be honest. How long till dull?

[UncleJoe]

Cutting mulberry and osage or (hedge) can eat your chain up quicker. Sometimes at dusk you see sparks fly cutting that
Osage.

Black Locust will do the same thing. I've cut locust at dusk and it can sometimes look like a 4th of July sparkler.

 

[Boog]

You should definitely not be getting dull after 8 rounds. If you are not hitting stones, dirt, etc as folks have already covered, the problem must be with the sharpening technique and/or the temper of the steel tooth. You mentioned that you use a grinder, so if your angles are all correct, than you may be overgrinding and ruining the temper of the metal. After many years of using different methods to sharpen, I have come back full circle to hand filing. I can put an incredible edge on a tooth by hand filing, never worry about overheating, and remove far less metal than grinding. I touch up my chains with a few (3-4) light strokes after each tank, never letting them get really dull in the first place. Takes very little time to do, and works very well for me!

 

[LLigetfa]

I can usually cut one truckload like this on one or two filings.

 

[Paulywalnut]

When the chain is cutting on a 45 degree angle its dull.

 

[Jon1270]

The greatest problem with the chains we buy today, is that they are not made from hardened steel. If they were, we could not sharpen them with a file.

This is wrong. Tool steels are routinely tempered to varying hardnesses depending on the application, and harder steels can absolutely cut softer ones, even though both have been "hardened."

 

[Charles1981]

I pass the hand file 3 times on each tooth after every tank. Takes less than 5 minutes. I have two new chains that I have had for over two years and haven't touched them yet. I think angle is getting off because the current chain is working less efficiently...but at this point I have sharpened it ~20-30 times can't really say for sure. Wondering if I am just getting to the end of its usefullness. It's been through about 15-20 chords of wood. It has eaten some dirt its share of a few times, and a chain link fence once (woops).

Anyway i am getting close to changing it out.

Generic home depot chains.