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Chain tensioning?

Brock Mayo

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Okay, stupid question here... when you tension your chain (with the saw sitting on the ground normally) do you lift up on the bar or let it rest? I like to lift up on it, that way if it pivots a bit during cutting it only gets tighter. What do you prefer? Thanks!

Brock
 

lxskllr

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I lift cause it's the factory approved method, but practically I don't think it makes a big difference either way. I tighten the bar enough I don't think it would move in use.
 

Frankie

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I pull up on the bar after I’ve snugged the bar nuts finger-tite , then adjust the chain-tension and then slowly tighten the nuts with the scrench ... I always make sure the chain is oiled/being oiled properly, most manufacturers say the chain should “sling” oil off the bar tip and this is good advice imho

 
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Brock Mayo

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Thanks guys, I do the same Burnham. I figured it was in the fundamentals Jerry, but it's sitting on my desk at work right now. Other than potentially bumping the chain a tiny bit looser or tighter while cutting, it seems like it could throw off you gunning by a few degrees. Not enough for me to worry about, because I'm usually off a few degrees
 

Burnham

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Be sure you are not applying even the least little bit of pressure off-line from parallel with the bar, either bucking or facing, with your grip and movement into the kerf. That's where we most often screw ourselves up in hitting the line we are aiming for. Sharper the chain, easier it is to drive the bar off your intended line, ime.
 

SeanKroll

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And don't tighten a hot chain. When it cools and shrinks, it can put pressure on the crank and bar tip. I've been told too much can bend a crank...dunno.
 

lxskllr

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If I tighten a chain during a cutting session, before I pack it away, I loosen it so it hangs off the bottom of the bar. I've heard a tight chain can do bad things to the saw. Dunno about bending a crank, but if nothing else, I guess it could mess up the seals. Loosening the chain's cheap insurance in any case.
 

lxskllr

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How tight do you all set it? I set mine so it'll snap down in place if you pull it up and release it. IOW, it doesn't lazily fall back to the bar, and it isn't a big strain pulling it up or anything. Just a nice snap when you let it go.
 

pantheraba

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On a 16" - 18" bar when I pull down "moderately" on the chain I can have 3 links clear of the bar....taught to me way back in an Ag. Extension chainsaw course. Never was translated into shorter or longer bars so I just guesstimate what is properly tight. I do loose enough to be able to move the chain by hand but not so loose that it hangs off the bar...snug to the bottom of the bar. Not real scientific.
 

pantheraba

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That's a good concise way to put it...that gibes with what I do (glad to be your esteemed company, Mr. B!) :D
 

lxskllr

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Next time I pull a saw out, I'll have to see how that compares to what I have. I suspect I'm tighter than that.
 

stig

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Brian said it really well, once:
No sag, no drag.
 

Frankie

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No sag and if you pull up with pressure the tip of the driver should NOT come out of the bar rail (in center of bar ) ... remember to clean the bar groove (either with tool or air-gun) before fitting chain / as part of routine maintenance as the chips / sawdust WILL accumulate and give erroneous results ... If I’m doing a job , the nite before I’ll clean the groove throughly, fit bar/chain and run saw bliping the throttle until oil is slinging off bar and/or dripping off the clutch cover ... this way everything is coated with oil ... loosen chain and the next morn when on job re-tighten chain and warm up saw - gtg and make $$$ , the chain stretches when hot and contracts when cool so NEVER leave it tight when finished cuttin ! Strains the clutch side bearing unnecessarily!
 

Magnus

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I have seen snapped cranks more than once. It is worse when they get bent, harder to figure out. Snapped is easy to spot right away.

If tension is proper and it lube enough it should Not get so hot that it stretches too much so you need to re tighten.
If so something is wrong. Common examples: Bad bar oil or too little oil, worn bar sprocket/beating or worn rim/bearing.
 

SeanKroll

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For me, it's no sag under the bar. No tighter than what it takes to get that, and not a smidge more. Short bar or long, same same.
This is how Stihl saw manuals teach you, and how I learned from a Stihl trainer.

Some people will run their 36" bars and up a little slack, allowing tool-less re-railing of a thrown chain, by bending the bar over, and working the chain back on, sprocket first, then the nose, then the sides. Not the gentlest on the bar..





Some people want to tighten up a slack chain that is hot and expanded from being run dull, low lube, twisting in the cut. The answer is to clean the oiling system, check the oil output, and sharpen the chain.


Stihl are 'pre-stretched' and are harder steel that stretches less than Oregon and others. Over the lifetime, Stihl needs less tensioning. New chains need tensioning the most after a little running.


Way back in the day our conservation crews worked with the the Exotic Plant Management Team of the NPS on Joint projects, sometimes. They used to have their chains stretch from lots of sand in the tamarisk/ 'salt cedar' bark, and eventually ran out of tension-ability, though the cutters were basically new. They would have to pull a link and re-loop it on 28" or so bars, maybe 24".
 
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Frankie

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I have seen snapped cranks more than once. It is worse when they get bent, harder to figure out. Snapped is easy to spot right away.

If tension is proper and it lube enough it should Not get so hot that it stretches too much so you need to re tighten.
If so something is wrong. Common examples: Bad bar oil or too little oil, worn bar sprocket/beating or worn rim/bearing.
Guys that file rakers excessively (.045-.055+) also are putting strain on crank and bearings not to mention hands ! Even on my hotwoods ported saws seldom do I go more than the soft setting on raker file gage which is about .030 in hardwood ... peeps think more depth of cut , faster cutting but I disagree (at least for hardwood) and have done testing to bear this out ... also too much depth of cut (raker st .050) makes saw grabby and potentially more dangerous to the saw operator ... The factory engineers designed raker for .026 and this is across all manufactured chain - this is for a reason , some think they are smarter than engineer who designed chain :D
 

Nutball

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I used to always lift the bar and tighten with it up:

to keep the chain from loosening during use,
to keep the bar better aligned to the sights,
and because I've seen it in the manuals.

It all started with my Echo 271t. I'd have to set the tension with its bar in the middle or slightly up because it liked to drift during use. That way it never got too loose or too tight.

Now I raise the bar, tighten the chain some, then let the weight of the bar add a little more tension before I tighten the nuts. I've found it to help get the tension right, and it seems to line up better with the sights. I've been finding lately having the bar all the way up doesn't quite match the sights, but every saw/brand can be a bit different. Another benefit to having the bar down a bit is I've found it to help make derailleurs a bit less frequent since the back of the bar is higher and the drive links have to enter the rails more directly instead of sort of falling down into the rails.
 

pantheraba

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Way back in the day our conservation crews worked with the the Exotic Plant Management Team of the NPS on Joint projects, sometimes. They used to have their chains stretch from lots of sand in the tamarisk/ 'salt cedar' bark, and eventually ran out of tension-ability, though the cutters were basically new.
Maybe that explains a problem we sometimes have. We have a Stihl Kombitool that lets us run a 12" bar and chain at ground level for brush cutting near the ground. (it has a 45" angle knuckle/elbow at ground level...it is like a pole saw but the bar can be used parallel to the ground easily). I use it a lot for maintaining bamboo groves and it gets dull pretty quickly being used that close to the ground. I reach a point where the chain gets loose and then, as Sean says, is no longer "tension-able"....at max tension it still hangs loose. It then jumps the track often and I have to get another new chain.
 

Frankie

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You can always take a hammer and punch , or preferably a chain breaker and remove a link and mend the chain together if chain is STIHL serviceable ...
 
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