Why does my chainsaw cuts turn left?

Recently, when I'm bucking logs, and trying to make a straight cut at 18", my saw starts veering to the left, and I end up with 1/2 the log at 18" and the bottom half 15 or 16 inches. I'm no expert with the saw, but I have cut enough to know how to easily cut a fairly straight line. It just seems there is an issue with the chain or blade?? I'm also noticing more sparks than I would normally see coming from the chain in the middle of a cut. Eye sight doesn't show the bar to be bent, but.....?

Whats the deal?

Worn bar groove, unequal length cutters , unequal height depth gauges any one of the three or combination will cause your problem, sparks sounds like oiler not working or supplying insufficient oil to bar/chain.

Most likely cause would be the chain not being sharpened equally on both sides. There is also a chance the bar is bent. Try a new chain to see what happens.

Thanks.... oiler ok, bar is nice and lubbed. I'm going to try a new bar and chain tonight, see what happends.

Tell us how you sharpen. Freehand (just a round file), round file in file guide, bar/bench mounted file system (like a Granberg File-N-Joint or Stihl FG-2), Dremel, dedicated electric chain grinder, other?

The first step I would take is the least expensive one. Clamp your bar (w/powerhead attached) in a bench vise and use a file guide with your file to sharpen your chain. Use more strokes per tooth than you normally use. For example, if you only make 3 or 4 strokes per tooth, try making 5-7 (or whatever it takes) to reestablish proper angle and tooth profile. In my experience, this is the most common fix for "curved" cutting with folks new to sharpening.

Also make sure that the file isn't rotating within the file guide as you make your strokes. If the file isn't secured in the guide, it will rotate along the long spiral of the round file, thus decreasing the amount of material removed during each stroke.

It's the bar.....

Chain not sharpended the same for each tooth, I know, I have done this and can cut curves really neat,, Have chain resharpend first and see,

As others have said . . . it could be several causes . . . but if you recently sharpened the chain and then noticed the curving it was probably the chain being over sharpened on one side.

Bingo! Thanks for help. Figured it out, was easy! I sharpned only one side! I lost track of what I was doing and went back to cut a few more logs and that's when I noticed it turning left. It was getting dark so I gave up...

Last night I bought a new chain at HD, and when I went to put it on I noticed 1/2 the cutters shinny and sharp, and the other 1/2 dull and dirty. SHIZER!! Sharpened it up, and made a bunch of cuts last night and it's workijn like a charm. Amazing how much it veered off with one side sharp.

Treepointer, I use the normal round file in a guide thingy. Works fine for me. I lock the saw in a Rockwell Saw Horse (love that thing) and file away.

I use the file guide thingy myself. As for a Rockwell sawhorse/jawhorse, it's on my "acquire" list. Glad you got your crooked cutting issue solved.

Get one, you won't be sorry. It's one of the few "infomertial" type products that REALLY is as good as they make it out to be. It's just so easy to use, and you tighten it with your foot, so it leaves your hands free. So nice that thing....

We need more thingys in our lives.

Not really! I have too many thingy's! I need to get rid of some thingy's!