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lose chains...

Started by HiTech, November 25, 2013, 06:55:12 AM

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HiTech

How many times have you seen someone cutting with a saw with the chain sagging down. I have seen some so lose you could stick your finger between the chain and bar. I had an old timer tell me years ago that a lose or slack chain will wear the drive socket out quick. Also from what I have seen those that run slack or lose chains are the ones who get the buildup in the bar grove. Plus it wears bars out quicker. I know to some it is sooo important to get that tree on the ground they can't take 30 seconds to tighten the chain. Also I suppose the chain could come off and injure you. Especially those who broke the chain catcher off.

redmule

 I try to keep just enough tension on my chain that it will pull the drive links back up in to the bar when it is pulled down from the under side of the bar.

Rob5073

I've heard some differing opinions on this but after you've run the saw for a while and the bar and chain have warmed up,  is it wise to allow it to cool somewhat before making a chain adjustment or can the adjustment be made immediately?

beenthere

I don't lose a chain very often but you're right, if they are too loose, then one could lose them.   ;)
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

redfin

I was taught many years ago how to tension a chain the way I have been doing it and have never lost a chain.

I hold up on the chain about 1/3 of the way in from the end of the bar. I tighten until I can just get a dime width between the driver and the bar.  Then, while still holding up on the chain tighten the bar nuts.

Not saying its perfect but has always worked well for me.

sawguy21

The chain will stretch from heat even with proper lubrication so I let it cool before making adjustments. I got careless at the end of the day, rather than get the brush cutter from the shed I started slashing brush with the saw, the chain was loose and a twig got caught between it and the bar.  The chain came off and tried to amputate my foot. Cost me a chain, I got off light.
old age and treachery will always overcome youth and enthusiasm

nmurph

Chains do not stretch (OK, maybe the links do grow 1 /100,000, but a chain doesn't get hot enough to produce meaningful change). The holes elongate and the rivets wear lengthening the chain.

thecfarm

I've have mine fall off more than a few times. I run my saw up and down the branches so the brush will lay down better. So that does not help. But have not had it happen for a long time. I like the brush in short pieces so it lays on the ground better and I can run it over with the tractor and I hope won't cause any damage to it. I do try to keep up how tight the chain is.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

Rob5073

Quote from: nmurph on November 25, 2013, 08:12:07 PM
Chains do not stretch (OK, maybe the links do grow 1 /100,000, but a chain doesn't get hot enough to produce meaningful change). The holes elongate and the rivets wear lengthening the chain.

Correct.  I believe it's more of a simple expansion / contraction of the chain and its components as it heats and cools, like any metal would.

7sleeper

Quote from: Rob5073 on November 26, 2013, 06:07:41 AM
Quote from: nmurph on November 25, 2013, 08:12:07 PM
Chains do not stretch (OK, maybe the links do grow 1 /100,000, but a chain doesn't get hot enough to produce meaningful change). The holes elongate and the rivets wear lengthening the chain.

Correct.  I believe it's more of a simple expansion / contraction of the chain and its components as it heats and cools, like any metal would.
That is true hot metal expands cool metal contracts. But these dimensional changes are so minimal you can forget them! If it wasn't true and we would notice it, what do you believe would the elongation be on steel bridge in the summer!?! That would change from flat to curved after your belief!

Another thing not mentioned so far is that hardnose bars require a more slack chain than roller tip ones! So as long as we don't know what bar then all discussion is mute. But even then there should be no room for a finger.
I have my chain so tight so that I can only pull off about one complete driver link!

7

JohnG28

As for bridges expanding in the summer, they are designed to do so. They have expansion/contraction joints. I know some reasonable sized bridges can expand multiple feet in length. Chain does expand when hot and will gain a little length.
Stihl MS361, 460 & 200T, Jonsered 490, Jonsereds 90, Husky 350 & 142, Homelite XL and Super XL

nmurph

Expansion joints have more to do with creating smaller load cells. Deflections caused by unequal weight changes and differing substrates are limited to shorter linear distances. Think about it like this- which is easier to snap, a very short pencil or a long pencil?

SawTroll

Quote from: Rob5073 on November 25, 2013, 08:38:58 AM
I've heard some differing opinions on this but after you've run the saw for a while and the bar and chain have warmed up,  is it wise to allow it to cool somewhat before making a chain adjustment or can the adjustment be made immediately?

Just remember to slack the chain before it really cools down, if you tightened it while hot
Information collector.

shootingarts

I think the closed loop of the chain exaggerates any chain length changes from heating and I think we will all agree that a chain gets very hot sometimes. Best I remember adding twenty feet to a pipe that went all the way around the world at the equator would raise the pipe three feet or thereabouts. The differences in length between a snug, tight, and loose chain just aren't very much length.

My chains are snug cold. A little loose after large cuts but unless they appear extremely loose, enough to toss a chain if they get in a little side bind, I leave them be. No harm tightening if you remember to loosen the chain at the end of the job or end of the day but I don't trust myself to always remember to loosen a chain. The worst case scenario of damaging a crank is too high of a price to pay for what I see as mostly as cosmetic issue anyway if trying to keep chain tension perfect all through the job.

Hu

7sleeper

Quote from: shootingarts on November 26, 2013, 12:32:46 PM

My chains are snug cold. A little loose after large cuts but unless they appear extremely loose, enough to toss a chain if they get in a little side bind, I leave them be. No harm tightening if you remember to loosen the chain at the end of the job or end of the day but I don't trust myself to always remember to loosen a chain. The worst case scenario of damaging a crank is too high of a price to pay for what I see as mostly as cosmetic issue anyway if trying to keep chain tension perfect all through the job.

Hu
I think you will be soon voted as the most sloppy wood cutter around for not constantly controlling your chain tension! I mean you should be cutting less and controling more! What happens to you if the chain tension controller shows up?! You'll be banned from working the rear handle of the chainsaw.....

:D

7

half_full

I learnt it this way: cool/cold chain, hold bar tip up, no sag, no drag. Meaning, tighten the chain while holding the bar tip up. Tighten until the chain is not sagging off the bottom of the bar and it's not so tight that it's not free to spin by hand.

JohnG28

Quote from: nmurph on November 26, 2013, 10:41:35 AM
Expansion joints have more to do with creating smaller load cells. Deflections caused by unequal weight changes and differing substrates are limited to shorter linear distances. Think about it like this- which is easier to snap, a very short pencil or a long pencil?

I must disagree, at least partly. Expansion joints are there mainly for the expansion/contraction of the bridge's structure. As for smaller load cells, you are correct. This is handled by lateral bracing between the main support beams of the structure. You can see these support members going between the beams traveling under a bridge. They increase rigidity and decrease deflection. I'm finishing a civil engineering degree with a focus on structural.  ;) One instructor, former DOT engineer had some specs on expansion of structures he had worked to design in the past.
Stihl MS361, 460 & 200T, Jonsered 490, Jonsereds 90, Husky 350 & 142, Homelite XL and Super XL

shootingarts

Quote from: 7sleeper on November 26, 2013, 12:47:10 PM
Quote from: shootingarts on November 26, 2013, 12:32:46 PM

My chains are snug cold. A little loose after large cuts but unless they appear extremely loose, enough to toss a chain if they get in a little side bind, I leave them be. No harm tightening if you remember to loosen the chain at the end of the job or end of the day but I don't trust myself to always remember to loosen a chain. The worst case scenario of damaging a crank is too high of a price to pay for what I see as mostly as cosmetic issue anyway if trying to keep chain tension perfect all through the job.

Hu
I think you will be soon voted as the most sloppy wood cutter around for not constantly controlling your chain tension! I mean you should be cutting less and controling more! What happens to you if the chain tension controller shows up?! You'll be banned from working the rear handle of the chainsaw.....

:D

7

I suspect you are absolutely right! I have been on more than one job where it seems that style points are far more important than performance. One like that annoyed me a bit and I picked one afternoon when our big wheels and the plant big wheels were hanging right where I was working. I did a most wondrous job, could have put the finished product in a textbook or on a magazine cover, but I took over two hours to do a thirty to forty-five minute job when the work would have been perfectly adequate in the shorter time period. My company wheels got antsy and sent a foreman over to see what was taking me so long. "Quality workmanship! You ever see anything so beautimus?" End of discussion.

Speaking of beautimus, a little something for the bridge side discussion. They built a most beautimus bridge down here thirty years or so ago. Kinda futuristic looking suspension bridge. Style points out the proverbial yaya. Over a mile long hanging over the Mississippi and tall enough for ships to go under. Only one minor flaw, neither the original futuristic road or any other road they have tried to build over it has lasted long enough to talk about. So far I think asphalt may have worked best! Sure is a pretty bridge though.

Hu

Rob5073

Quote from: SawTroll on November 26, 2013, 11:08:17 AM
Quote from: Rob5073 on November 25, 2013, 08:38:58 AM
I've heard some differing opinions on this but after you've run the saw for a while and the bar and chain have warmed up,  is it wise to allow it to cool somewhat before making a chain adjustment or can the adjustment be made immediately?

Just remember to slack the chain before it really cools down, if you tightened it while hot

Makes sense in order to prevent seal damage.  Thanks. 

nmurph

Well, this should be easy enough to prove one way or the other. Someone needs to measure the link of a chain cold, then check it hot. I'm betting you can't measure the difference.

HiTech

Wow!!! Sorry guys didn't mean to get everyone soooo upset about taking care of their equipment and perhaps their safety.

HolmenTree

Stihl used to mention in their saws owners manual to loosen a chain off at the end of the day to avoid crankshaft bearing damage, but that was back in the day and haven't seen that ever printed again.
A little trick to ease chain tensioning whether on the work bench or on a stump. Turn your saw over on its back , loosen the bar nuts and let gravity put the bar in position for you, tension the chain until chain contacts bar , then retighten nuts.
Longer b/c may need slightly more tension.
Making a living with a saw since age 16.

Jeremysdad

Much like a tire 'sings'...so too does a chain 'sing' before it takes your arm off. :) That wasn't less than 2 words!!! lol

Jeremysdad

I just injected 2 turkeys with flavored butter that I clarified. I never promised that I would make sense. :)

Jeremysdad


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