Crooked cuts, Bent bar? Bad chain? Poor sharpening?

Bent bar. Quite frustrating isn’t it? Mine got bent when it remained stuck in a 30 inches Norway spruce. I wonder if it is possible to straighten it somehow...

It's more often the chain than the bar. Imo.

Chainsaw bars wear unevenly as the inside of the bar gets more lubrication from the oiler. Often your problem is caused by this uneven wear. Visually inspect the bar by looking down the length of the bar along the edge to see if one side is "higher" than the other. If so, dress it with a flat file. You can reduce the effects of this wear pattern by turning the bar over with every sharpening.

Bars wear out, of course. See http://www.madsens1.com/bnc_bar_maint.htm for a good explanation of how to check if a bar is past its sell-by date.

My own experience is that a worn chain cuts poorly and erratically rather than a consistent pull in only one direction.

Was cutting some 36" poplar with a 20" bar, and was drifting quite a bit. Didn't have a new bar, but put a new chain on and it helped tremendously. Still think I need A new bar too. So I think Both can be a factor.

Bar is easy to remove, inspect, and rule out.

Chain is a bit tougher to see. I'm betting on the chain, a lot of people sharpen one side with greater force than the other.

+1 on the chain, easy enough to find out, go buy a new chain and see if your problem disappears. I had this once it was after I aggressively hand filed the chain, and filed the rakers, it cut OK, but crooked as a dogs hind leg.

+1 on chain being the cause
Sometimes it's easy to sharpen right hand v. left hand sides of the chain differently (more aggressively), especially when hand filing, causing cut to veer crooked. This won't be apparent on quick, small cuts (saw seems sharp), but becomes noticeable on larger diameter cuts. A file guide (like the 2-in-1 Pferd/ Stihl file guide) should help fix this problem.

CincyBurner said:

+1 on chain being the cause
Sometimes it's easy to sharpen right hand v. left hand sides of the chain differently (more aggressively), especially when hand filing, causing cut to veer crooked. This won't be apparent on quick, small cuts (saw seems sharp), but becomes noticeable on larger diameter cuts. A file guide (like the 2-in-1 Pferd/ Stihl file guide) should help fix this problem.

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+1

That's been my experience, too. When I first started hand sharpening, I had some crooked/drifting cuts in larger wood. I made a point to pay more attention to filing the cutters on both sides the same way. The biggest problem I had back then was that I was using too few filing strokes to get the cutters true again.

DodgyNomad said:

Bar is easy to remove, inspect, and rule out.

Chain is a bit tougher to see. I'm betting on the chain, a lot of people sharpen one side with greater force than the other.

Click to expand...

It is very hard to master properly hand filing chain....back when I hand filed I would have to take the chains in to be sharpened on a grinder to get the angles back on track every 4th or 5th sharpening...the chain was the culprit every time...

Very easy to rule the bar out or confirm - flip it over & see how it cuts then. If it still cuts crooked but the other way then ya likely the bar. If it still does the same thing, it's your chain.

Check the gap between the rails on the bar, move chain side to side, there should be very little movement. along with flattening both rails the gap also needs closing every so often(special tool).

If the bar needs attention your local saw shop can recondition the bar for you.

Pickup the stihl 2in1 sharper for your chain size.

You will not be sorry!

. . . and the take from Madsen's http://www.madsens1.com/bnc_cut_pull.htm

BenTN said:

Check the gap between the rails on the bar, move chain side to side, there should be very little movement. along with flattening both rails the gap also needs closing every so often(special tool).

Click to expand...

You have a link or more info about this special tool?

maple1 said:

You have a link or more info about this special tool?

Click to expand...

https://www.forestershop.com/bar-ra...ductid=bar-rail-closer-forbrc&channelid=FROOG

First one on google.

maple1 said:

You have a link or more info about this special tool?

Click to expand...

No special tool required...
Vise or hammer and an anvil or other hard surface to hammer the bar on.
Find a suitable gauge to check the space as you slowly hammer the bar back together a few taps on each side as you work your way along the edge.Your eyes are the best tool as you work the bar.With a vise you can squeeze the rails back together using a suitable gauge and you eyes.You can straighten a bar the same way. Straighten first then retune the rails.

What size chain are you using?

My money is on bar being worn on one side.

In my experience it can be a combo of a worn bar and an improperly sharpened or dull chain, but most likely it is the chain . All of the cutters should be the same length ( flip the chain over on itself to compare a right hand cutter length to a left hand cutter length ) . Also the rakers need to be dropped an equal amount . Also, sometimes when cutting ( even with a new chain ) the cutters on just one side can hit something hard and dull up that side causing the chain to pull in the direction of the sharp teeth . Another thing to check is the forward rake of both left and right hand cutters , they should be the same as well ....................

I am not a believer in the even tooth length theory. All my saws currently have uneven length teeth and cut as straight as new. The video below is long but he shows just how far off teeth get and still cut straight. Buckin sure knows his stuff when it comes to saws and cuttin.

Try setting the bar on edge on a flat surface. See if it will stand up straight.

If not, one side is worn more than the other. You can buy a file and jig to file the edge flat again.

Bars and chain wear out. But not after 5-6 times out, or 5-6 sharpenings. A chain used and resharpened 50-60 times maybe. Sharpening technique? Maybe take it in and have it machine ground to straighten it out. There are ways to measure and tune a chain, but wondering if you would want to go that route.

Every so often I do have the same problem you are having. The bar/chains would be used for a long time, and clearly wore out. Filing the bar flat and removing burrs, and a couple new chains solves the problem of bowing within the cut, as does getting a complete set bar and chain. Look up how to gauge if a chain/bar settup is worn - push the teeth to one side, use a straight edge on the side, etc.