Saw Does NOt Cut Straight

Menchhofer · Sep 15, 2004

Have Sthil 036 Pro and it has started to cut to the right.

I checked the cutters, all are equal length. Put new bar on a few weeks ago and it still cuts crooked.I re-checked the bar .....looks even also.

Bottom of chain looks okay too.

Why does it not cut straight......thought I would ask you professionals out there. Appreciate everyone's thoughts.

MasterBlaster · Sep 15, 2004

Your not filing each side with enough precision, it has to be exact.

My eyeballs frig me up on filing.

Crofter · Sep 15, 2004

You say you put on a new bar several weeks ago. Did you put the new bar on with a used chain.

MasterBlaster · Sep 15, 2004

And you might have a wire edge on your bar. Every time you take your chain off, you need to inspect it for that, and flip the bar over when you put it back on.

MasterBlaster · Sep 15, 2004

Or, the spark plug! :blob2:

xander9727 · Sep 15, 2004

Have you check the muffler bearings?

monel_funkawitz · Sep 16, 2004

Check the rakers too. Does it cut crooked with just one chain or multiple chains?

To cut crooked, one side of cutters on the chain has to cut more or better than the other side. It is very easy to file teeth unevenly on the left or right side if you file by hand. The only real way to go is hit it with a good chain grinder and get all the top plates the same exact length, and get all the rakers all exactly the same length. Then you can hand file about a half dozen times before dusting it off with the grinder again to make sure your angles are spot on. I get a sharper chain with hand filing, but no one in the world can hand file the angles as accurately as a chain grinder.

Get a new chain and the problem will go away. Chains are cheap.

Crofter · Sep 16, 2004

If a chain has been run in a situation that causes it to cut crooked, more pressure is put on the tie straps and one side of the drive tangs. Uneven weaar occurs. Even if you give it a 100% uniform sharpening as to angles, lengths and rakers, the uneven wear to its guide surfaces will very likely allow it to resume its errant ways. If you cut for any length of time with the chain running off you ruin both bar and chain! Stop and fix it at 1st sign.

monel_funkawitz · Sep 16, 2004

Makes sense.

I never get to this stage because I'm religious about the four chains, two sprokets, and one bar routine. I flip my bar everytime I file, dust my chains on a grinder every six filings or so, file every two tank fulls or when I don't like the way it is cutting, and if I nick something like a wedge (I use metal ones, screw plastic ones.

) or barb wire or something, it gets taken care of when it happens. Plus I use buttloads of bar oil and I never get into a situation where I can pinch or bend the bar.

Never had a saw cut anything but laser straight. Course I don't do it on a pro level either, so I'm not strapped for time or cash.

Tony Snyder · Sep 16, 2004

Here we go again.

If it was cutting crooked and you changed the bar, then the uneven wear pattern could have been present on the side straps of the chain , thus part of the problem would remain. The chain probably should have been changed, but then again, as mentioned above, drags could have been a factor. These things feed on one another. Some times you just have to start completely over.

But, this is all basics, no mysteries here.

You see this around a saw shop frequently. You usually do not see it with experienced users.

Menchhofer · Oct 2, 2004

I went ahead and purchased a new bar, chain, and sprocket rim so I will probably not know what was the actual problem.
I appreciate everyone's help.

The bar...chain...and sprocket all seemed in good condition which was why I was puzzled.

MasterBlaster · Oct 2, 2004

Well, it outta cut like a beeyotch! :blob2:

Chainsaw Master · Oct 3, 2004

ahhhhhh what about mismatched bar & chain guage.......if its all new.....sounds like 50 guage chain in a 63 bar......

Gypo Logger · Oct 3, 2004

Just a thought, but could you have a 1.3 mil chain in a 1.5 mil bar? The bar groove width is stamped in the bar, ie, 1.3 - 050. Stihl chain has a 3, 5 or 6 stamped in the drive tangs, denoting 1.3, 1.5 or 1.6 mil thickness. Asumming that all Stihl bars start off as 1.3, then this probably isn't the cause.
John

Gypo Logger · Oct 3, 2004

The BRC works well, but only if used in conjunction with a BRS- Bar Rail spreader. First close rails about .3 mil, then with a stihl 1.3 or 1.6 BRS open up the rails. This requires some finesse and practice to not overdo the BRCing. Both faces of the bar should be dressed with an orbital sander first to remove any edge. Stay away from the tip and heel of the bar as much as possible.
John

Crofter · Oct 3, 2004

Originally posted by Mike Maas
I gotta disagree Tony, I ran saws a long time and never figured out diagnosing crooked cutting until recently. It can be quite a puzzle.

Tony; To stop Mike from quibbling you have to differentiate between EXPERIENCED and COMPETANT.
By his own admission he was one but not the other! Seriously though it is easy to get chasing your tale with cutting crooked conditions, to the point of not knowing where you are or were. Compensating wont work for long; as Mike points out you have to find the real cause. The important thing is to correct it immediately so you don't transmit uneven wear to other parts that will haunt you. Immediately does not mean when you empty that tank of gas.

Al Smith · Oct 3, 2004

Bar repair,my method

I use a 6 by 48 belt sander,to dress.I have several sets of tapered wedges,which I made,for spreading,and a 12 inch milling machine vice for closing.I realize,not everyone has a machine shop,but this is just my method,and it works well.I imagine a person could remill a bar from .050,to .063,but I 've never done so.

Tony Snyder · Oct 3, 2004

I have found that bar rail closers do not work well. You cannot restore the inner walls of the rails to parallel. When the bars get bad enough to need closing, it is asually time for a new bar.

Unfortunately (much of the time)when crooked cutting occurs, the problem has gone beyond a simple sharpening problem. Often both the bar and chain are damaged. They are like Mike shows, or maybe worse.

Regarding bad sharpening, the most frequent filing mistake I see is the operator allowing the saw motor to crowd him when sharpening from the left side. You have got to train yourself not to let that saw outsmart you. Do your filing up nearer the nose of the bar.

bighoss550 · Oct 3, 2004

my saw was borrowed a while back. it nicely came back cutting crooked and half the cutters filed away...... isnt that nice??
i have been having problems with crooked cuts (after a new chain) since and i am now enlightened as to why

thanks guys....

MasterBlaster · Oct 3, 2004

Originally posted by Mike Maas
What works best for me, Tony, is to turn the saw upsidedown in the vice. That leaves the powerhead on the right side, totally out of your way!

Doesn't that frig up the carb with gas, or something?

Saw Does NOt Cut Straight

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