Chain saw curving while cutting question

[beppington]

I have a Stihl HT101 polesaw. I installed a brand new chain last weekend & made only about 3-4 cuts, cutting the tops of recently installed 4x4 fence posts. Seemed to cut those fine.

We've been using this saw to cut 4x4 fence post tops because I can use a level & get a nice flat-top cut :thumbsup: My dad operates the powerhead while I guide the saw end making the horizontal cut. This has worked really great on about 300 previous posts :thumbsup:

So ... Next time we used the saw with the new chain (last night) to cut off a bunch more posts, the saw was really grabby & when I went ahead & let it start cutting into the wood it immediately curved upwards very strongly; I couldn't stop it from curving. We tried several more posts & every one was the same. My previous experience with curving chainsaws is simply, dull chain. But this chain is basically brand new :confused3:

It also seemed like the chain & bar was really hot :confused3: We tried adjusting the chain to make sure tension was proper, which it already was; Made sure everything was oily, & it was. I went ahead & cleaned the bar & bar holder area & tried it again: Same result. Super-curving cuts & bar got really hot very quickly.

I still had my previous chain, so I put it on instead & the saw cut fine; We were able to finish cutting all the posts with it. I was only using that new chain for insurance, to make sure if the previous chain had any dullness I would be avoiding having any curving cuts & therefore crooked fence post tops.

Anyway, when I got home I inspected each tooth on the curving chain. Every single one seems really sharp, no nicks or dullness I can see. It's all shiny as you would expect a new chain to be.

I also lined it up against an older, worn chain that worked great for a good while, & they look just like you'd expect; They match each other to a tee except the curving one looks new & the older one is a little dirty & its teeth need sharpening.

I will say, I'm still using the original bar & sprocket after about 3 years. The bar looks fine from what I can tell, but the sprocket does have some grooves in it. My dad thought the curving chain sounded "clicky" when I rotated it by hand, whereas he thought the old one I put back on didn't have the clicky sound.

While I have used a chainsaw many, many times, I wouldn't say I'm any kind of expert on chainsaw sharpening or determining for sure if one is sharp or not. I've always just used a chain until it's spitting out fine dust/ powder (usual) or starts curving (far less common).

Sorry for the long post ... But, from all this, what do you think is causing that chain to curve off so strongly that I can't even fight it??

 

[DavidNPro]

That is interesting, any time I have seen this happen was due to one side being sharper than the other. Often times while cutting we would quickly dress up a saw, and if the person dressing it up didnt get the teeth going each way almost the same you end up with that curved cut. We always fixed it buy spending a little more time on the opposite side it was curving to.

Never seen it was a new chain though like you are saying.:confused2:

 

[mmorisoli]

I have the HT131 and just love it. I also bought the angled head which is the best investment I have made for that saw! (I use mine for trimming Oak Trees)

Typically if a person sharpens their own chains they may get one side sharper than the other. Its easy to do over time if you are not judicious about using the same method for each side of the chain.

Another problem I have seen is if the bar is worn a bit more on one side of the track than the other. It will cause the chain to sit a touch askew and will cause the cut to run in the direction of the worn side. The quick test is flip the bar over and see what happens, but I would buy a new bar, they are cheap and they do wear out.

 

[xyz123]

Check bar groove to make sure they are even across and not wore uneven or grooved. Take flat file to it if not.

Bar and chain tips and scroll down for pics in the lower right. http://www.oregonchain.com/homeowner/service/maintenance_tips.htm

 

[beppington]

Ah, yes, I did check the bar: It's groove seems nice & even, no obvious dents or nicks.

I will give it a try flipping it over.

 

[Brad_Blazer]

I've had chains ruined from hitting metal where it rounded off an outside corner of all of the teeth. Sharpening didn't help because the defect was on the outer surface. It would cut, just not straight.

 

[SPYDERLK]

Are you sure you didnt hit a nail or something hard that caused the grabbing? That will sure make em grab and ding the teeth. It should be pretty noticeable tho. :confused3:
larry

 

[beppington]

Are you sure you didnt hit a nail or something hard that caused the grabbing? That will sure make em grab and ding the teeth. It should be pretty noticeable tho. :confused3:
larry

I just really don't think so. I guess I cannot guarantee it, though. And there are no visual signs at all, to me, the non-expert of course.

 

[SPYDERLK]

One identical chain works and the other doesnt says somethings not identical. ...

 

[Egon]

Chain gauge ??

 

[beppington]

One identical chain works and the other doesnt says somethings not identical. ...

Apparently identical :thumbsup: ... as judged by an admitted non-expert on chainsaw chains.

 

[jonyyuma]

Time to get out the Big Magnifying glass???Plenty of people want to see a photo of these two mystery chains?

 

[nobull1]

Chain gauge ??

I don't know if the wrong gauge chain will fit in the wrong bar but if it could then that could be the problem. The thing that sticks out to me which could be the problem or contributing problem is the hot chain and bar. Is the sprocket smooth feeling? Is the oil spraying on the ground when reved up and held close to the ground, with the problem chain?

 

[wade simpson]

When I bought mine the dealer said to flip the bar after a few shapenings and do that until niether side will cut straight, then replace it.

 

[massey990]

When I bought mine the dealer said to flip the bar after a few shapenings and do that until niether side will cut straight, then replace it.

I always reverse (flip) the bar whenever I sharpen the chain, this prevents it from extreme wear on a bias.

 

[arrow]

If its not the teeth its the runners. Egon gives you a clue by checking gage with a micrometer. You are building heat because your tangs or drive links are causing some type of abrasion against the bar. It is obvious that these chains are not identical and if the cutters are not giving you a clue, and you checked the tension then it could be nothing else but the tangs or drive links. Check chain gauge and sprocket to drive link engagement

 

[RandyT]

Could there be a possibility that one chain has .043 drive links and the other have .050 drive links. running a .043 in a .050 bar will cause a saw to cut crooked.

 

[LD1]

Yep, check the drive links of BOTH chains and compare to what the bar requires. (usually stamped on the bar.)

IF the one chain works and the other dont, that leads me to believe that the chain is the problem, NOT the bar. And since you are cutting post tops, and not down in the dirt or hitting nails, I doubt it is a dull chian. And if you have not attempted to sharpen or lower the rakers on this chain, it should be good "top-side".

Get out the calipers or mics and check the thickness of the drive-links. Common ones are .043, .050, .058, and .063

As others have mentioned, if one is an .043 and the bar is made for .050, there is too much slop and it will cause a crooked cut.

 

[Deere Dude]

I had a similar problem with my regular chainsaw. I would cut a 10" log and even though I would start perpendicular to the log, by the time I got through it I would curve it by 2-3 inches over.

I found that when I installed the bar on the saw there was a tiny lip on the stud near the base and the bottom of the bar was riding on that instead of totally flat on the base. I just made sure the bar was flat and not riding on any saw dust or that little lip on the stud then all was fine.

 

[yomax4]

Dull chains cause you to bear down a little more with the left had on the bar. Causes me to cut slightly to the right. Sharp chains do all the work but you still have to watch and steer to get a really straight cut. Some guys have had faulty sharpen jobs where only one side of the chain was sharpened. That too will cause an angled cut.