Dull chains...does it really kill saws....how?

[Brewz]

yes i did , but what do you think of it

may as well put the chain in the dirt to touch it up

 

[peter92]

may as well put the chain in the dirt to touch it up

i think ive seen something like that before , but i like hand filing as ive never used one of those electric wheel ones

 

[David Young]

Friction. Pure and simple. Dull cutters don't cut, they RUB. That causes friction which builds heat on the chain. Lean on the saw and your adding more friction. The chain carries the heat to the crank and so on.

best answer?

the added rev because of no loading is not what kills them.

friction/resistance causes heat.
Thats your problem and it would take less time to learn to file than it would to wrastle with a dull saw trying to get through would.

 

[DSS]

A saw is normally tuned so it cleans up under load. If the chains dull it never cleans up, so it's basically screaming all day. Boom.

A guy gave me a plastic poulan a couple of years ago, he said it runs fine but it won't cut at all. I'm getting a new one, tired messing with it.

He was right. And it cut fine after I turned the chain the right way round

 

[Brewz]

best answer?

the added rev because of no loading is not what kills them.

friction/resistance causes heat.
Thats your problem and it would take less time to learn to file than it would to wrastle with a dull saw trying to get through would.

True
and the bar would be a great conductor of the heat into the case

 

[peter92]

A saw is normally tuned so it cleans up under load. If the chains dull it never cleans up, so it's basically screaming all day. Boom.

A guy gave me a plastic poulan a couple of years ago, he said it runs fine but it won't cut at all. I'm getting a new one, tired messing with it.

He was right. And it cut fine after I turned the chain the right way round

hahaha

 

[Brewz]

i think ive seen something like that before , but i like hand filing as ive never used one of those electric wheel ones

I am a fan of learning to hand file
I can get a chain very sharp with a hand file. Like slit you open sharp but I was stood in a training center for a year as an apprentice 25 years ago and trained how to use a file along with other hand tools.
I have tried electrics and cant get them to do the same job.

 

[peter92]

I am a fan of learning to hand file
I can get a chain very sharp with a hand file. Like slit you open sharp but I was stood in a training center for a year as an apprentice 25 years ago and trained how to use a file along with other hand tools.
I have tried electrics and cant get them to do the same job.

its like teaching an old dog new tricks , im not looking forwards to sharpening those long chains for milling by hand , thats for sure

 

[Mattyo]

OK ok ok ok..... I'm not proposing running dull chains. I'm just looking for the actual mechanism of saw death because of a dull chain. What actually kills the saw? So, so far @redtractor seems to have the best answer. Dull chains RUB ... causing heat which builds up on the bar, which builds up on the crank and bearings, and then I would assume causes an air leak when the seal melts. OR, somehow adds enough heat to the motor itself so that the internal lube can't keep up (especially at 50:1?)

Certainly I would agree that running a saw at WOT no load isn't good for it, and say... WOT is 13k rpm...no load is bad... then why exactly is 12k with load good for it? does that 1k rpm less generate that much less heat ....or is that 1k rpm mean that cooling is able to keep up better? I would think there would be more heat under load.


back to the air filter ... yes, assuming a fixed amount of fuel, if you take away air, then the fuel in that ratio goes UP. I forgot that carbs are air based, and they draw less fuel based on less air....until they simply don't run at all anymore. that would make sense...

 

[Dub11]

OK ok ok ok..... I'm not proposing running dull chains. I'm just looking for the actual mechanism of saw death because of a dull chain. What actually kills the saw? So, so far @redtractor seems to have the best answer. Dull chains RUB ... causing heat which builds up on the bar, which builds up on the crank and bearings, and then I would assume causes an air leak when the seal melts. OR, somehow adds enough heat to the motor itself so that the internal lube can't keep up (especially at 50:1?)

Certainly I would agree that running a saw at WOT no load isn't good for it, and say... WOT is 13k rpm...no load is bad... then why exactly is 12k with load good for it? does that 1k rpm less generate that much less heat ....or is that 1k rpm mean that cooling is able to keep up better? I would think there would be more heat under load.


back to the air filter ... yes, assuming a fixed amount of fuel, if you take away air, then the fuel in that ratio goes UP. I forgot that carbs are air based, and they draw less fuel based on less air....until they simply don't run at all anymore. that would make sense...

Well 13k for 2min or 12k for 15 seconds

 

[Dub11]

And stuff that spins has a life span who knows how long bit why have it spinning more than needed. Thats one reason why diesel motor last longer they spin way less than a gasser.

 

[Guido Salvage]

OK ok ok ok..... I'm not proposing running dull chains. I'm just looking for the actual mechanism of saw death because of a dull chain. What actually kills the saw? So, so far @redtractor seems to have the best answer. Dull chains RUB ... causing heat which builds up on the bar, which builds up on the crank and bearings, and then I would assume causes an air leak when the seal melts. OR, somehow adds enough heat to the motor itself so that the internal lube can't keep up (especially at 50:1?)

Certainly I would agree that running a saw at WOT no load isn't good for it, and say... WOT is 13k rpm...no load is bad... then why exactly is 12k with load good for it? does that 1k rpm less generate that much less heat ....or is that 1k rpm mean that cooling is able to keep up better? I would think there would be more heat under load.


back to the air filter ... yes, assuming a fixed amount of fuel, if you take away air, then the fuel in that ratio goes UP. I forgot that carbs are air based, and they draw less fuel based on less air....until they simply don't run at all anymore. that would make sense...

Research is needed... Grab a saw and a dull chain and run it until it dies and then pull it down, you will then have your answer.

 

[cus_deluxe]

Beating a dead horse a bit, but think of how a properly sharp chain cuts. It self feeds, meaing no down pressure on the bar is required to cut, the chain is actually pulled away from the bar in the cut. Bar oil is allowed to do its job. A dull chain must be forced, pushed down, so that chain is in direct contact with the bar under lots of pressure.

 

[jimmorrison]

Red tractor all the way, it is the heat. If the components can take it and keep running. The fuel will boil and the saw will lean seize.

 

[Philbert]

Do they work Tony , have you used one

Stupid idea if you ask me

may as well put the chain in the dirt to touch it up

http://opeforum.com/threads/powersharp-chains.5620/

Check out the cut photos.

Philbert

 

[MustangMike]

Get out a heat gun, I will bet $ to donuts that a dull chain will increase the temp at the exhaust port, cause the saw is working harder to pull a dull chain through wood, and that will increase the chance of a heat failure to the piston.

 

[Lone Wolf]

Ok....completely serious question...as raised on my youtube channel.

How does a dull chain kill a saw?

Doesn't it put less load on the engine? Sure it revs high for long without doing any work...but what is the actual mechanism of failure....

You kiddin me?

 

[Lone Wolf]

With a dull chain the run time on each cut is much longer and typically the operator is leaning on the saw hard to compensate. Dull chains create dust that can be invested (rather than chips) and long cuts create heat buildup.

Nailed it! I know this but you got it first and it is correct!

 

[MustangMike]

its like teaching an old dog new tricks , im not looking forwards to sharpening those long chains for milling by hand , thats for sure

I have done some milling before I started using square file chain, which I sharpen by hand.

I was running Stihl narrow kerf rip chain, and sharpening it with one of those 12 V hand held sharpeners. They are not that expensive, they have a guide on them, and they work very well if you adjust them right and replace the crap stone that comes with them with an EZ Lap diamond stone. If you are looking for a fast and easy way to sharpen your milling chain, this is it. Just remember, rip chain is filed at 10 degrees, not 30, and the narrow kerf teeth use the 5/32 stone, not the 7/32 for regular 3/8. (Warning, the crap stone that comes on those sharpeners will not even last for one full chain, get the diamond stone right off the bat, they work & hold up very well).

You can not buy this chain from a Stihl dealer, as Stihl produces it exclusively for Logosol, and Baileys is the exclusive importer for Logosol. They will tell you you need a special narrow bar to run this chain, but the bars were back ordered when I got the chain, and the chain worked just fine on my regular Stihl bars.

Hope thin information helps you.

 

[Mattyo]

Mike, that is an interesting suggestion about the infra red gun.... But I would still contend that its easier for a saw to pull a dull chain... hence the higher rpm.