Odd situation : only half of chain teeth beat up

[frogpond]

I went to sharpen the chain on my Stihl ms261cm after it got dull( probably hit some dirt while bucking up a maple). Only the teeth pointing one way had ragged cutting edges, while the ones pointing the other way were just a little dull, but undamaged. What could hsve caused this?
It's a Stihl semi chisel 3/8 chain on a 20" lightweight bar.

 

[4570Man]

It’s pretty common for chainsaw chains to just get damaged on one half. A gravel stuck in the bark could have easily done it.

 

[Hay Dude]

I have had this happen and found something stuck under the removable sprocket drive cover.

 

[Runner]

Happens to me all the time, hit a rock, nail, piece of fence wire with the bar tilted to one side and it only dulls the teeth on that side.

 

[ruffdog]

Years ago I found square nails deep inside an old oak.

 

[Runner]

The worst of it is that now you will have to sharpen those teeth more than the other side and will wind up eventually tossing a chain with only half the teeth worn out.

On the brighter side, the difference in size of teeth doesn't really affect the cutting or tracking of the chain...

 

[Rockbadchild]

happens all the time, the debris was on that side or its simply that side that caught it. Is you rakers files down the same ? that's could impact this if it's not the case but then your saw would cut crooked as well.

 

[frogpond]

Oh well, so much for my theory about one-armed gremlins...
I file all the rakers the same. I use a Stihl 2in1 for filing, and also round the leading edge of the rakers after a while. After this occurrence, I filed all the teeth to the same size, of course.

 

[Rockbadchild]

Oh well, so much for my theory about one-armed gremlins...
I file all the rakers the same. I use a Stihl 2in1 for filing, and also round the leading edge of the rakers after a while. After this occurrence, I filed all the teeth to the same size, of course.

I don't do that... I file it until its sharp and stop, yes I end up with some teeth longer then others but next time it could be the long one that get hit...

 

[Jrasband]

Oh well, so much for my theory about one-armed gremlins...
I file all the rakers the same. I use a Stihl 2in1 for filing, and also round the leading edge of the rakers after a while. After this occurrence, I filed all the teeth to the same size, of course.

I also use the stihl 2in1 and find it excellent.

I disagree that it is necessary to sharpen the teeth evenly, I think you are wasting material, time and chain life by doing so.