Breaking chains!

[7ShawnT]

I bought an older Stihl 021 off of ebay about 3 months ago, it came with 4 used chains, I just broke the 3rd chain this afternoon! They did not appear to me to be worn that much, but that is why I am asking you! There was still alot of teeth left that is why I say they were not worn out.

The last time I used this saw I had sharpened the chain just before, and something strange happened while sharpening it, the chain refused to go around, so I could get to the next tooth, it acted like the chain brake was on! I checked and it was not on, and then I tried to reverse the direction of the chain and it went the other way, but hung up in this one spot, so I just finished sharpening it, when I was done, it slid around in either direction!

While I was cutting with it last time, I noticed that sometimes when I went to rev up the saw, the chain would catch, like it was stuck, then it would go, once I had to help it, by nudging the tree, and then it was free, I could rev it up and cut. I also noticed that if I cut with the center section of the bar, not right up close to the saw, it would make a chattering noise as I was cutting.

With all of that said is it me, old junk chains, the saw, maybe clutch, or brake? I am going to try to include some pictures, I also checked the bar sprocket teeth, and they turn smoothly.

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Are the lower (inside) drive teeth of the chain supposed to look like this?

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It does appear that is some kind of wear on the drive sprocket.

Thanks for any help you can provide!

Shawn

 

[TDunk]

For a wild guess, i'm gonna say replace your drive sprocket and see what happens. Good pics though.

 

[mountainlake]

Get a new sprocket and chain, never saw a sprocket wore that far. Steve

 

[RDT]

It looks as though sprocket needs replaced not sure if that is your chain breaking problem. Im kinda new to this chainsaw thing Im sure one of the pro's can help you out.

 

[Austin1]

For god's sake get a new sprocket!Oh and replace your chain the drive links may have been damaged or you might be able to touch them up with a file.

 

[Tzed250]

I would replace the whole cutting system, sprocket nose may be cashed out too. Check the oiler while you are at it.

 

[B_Turner]

Holy carp. That is a pretty scary looking "sprocket."

It takes a lot to break a modern chain. Something really bad going on there. I would consider putting in a floating rim kit. A friend did it on an old 028 and it only took a few minutes to swap parts.

Like already has been said, the very great pics tell the story clearly. The focus is actually on the part we want to see.

 

[16:1mix]

FWIW,

Are the chains a different pitch that the drive sprocket?

 

[rreidnauer]

LOL, Wow! Yea. Worn just a wee bit.

Great pics, makes for an easy diagnosis.

Gonna run like a whole other animal if you get the sprocket,chain, and bar replaced.

 

[B_Turner]

FWIW,

Are the chains a different pitch that the drive sprocket?

That's a good question. Wonder if you've got 3/8 chains on a trashed .325 drive.

 

[Austin1]

That's a good question. Wonder if you've got 3/8 chains on a trashed .325 drive.

Good point I have never seen anything like that before!

 

[tree_beard]

seen that before

sprocket looks much like one i had on an old e-bay cheapy i got recently, didnt run it mind, examined everything first and it looked like a liability.

as for the chain snappage... look at the bottom of the tie-straps on the chain pic, pretty worn where the chain has been running in the grooves worn into the sprocket teeth.

un-usual yes, but running chains on knackered sprockets makes them wear in unusual ways.

my 2pence... for what its worth (about 4cents)

 

[7ShawnT]

More info . . .

I believe that good photos help get good answers, If I do my part, then you can SEE what I'm talikng about! Thanks for all the input so far!

B Turner wrote "I would consider putting in a floating rim kit." what is that?

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16:1 mix wrote "FWIW,

Are the chains a different pitch that the drive sprocket?" not sure what you mean by that.

Also what does "FWIW" mean

I have included some more pictures with the chain over the sproket. I'm not even sure what size it is, but it is a "small" size chain, not like I had on my 056 a bunch of years ago, which my dad sold for me at a yard sale for $25 because the guy couldn't start it!

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tzed250 wrote "Check the oiler while you are at it." I use about 3/4 or more of a tank of oil per tank of gas, there does not apear to be any adjustment for the oiler.

I do not have a manual for it, I tried to get on at Stihl's website, but they don't have it listed, and I asked them to send me one, not sure if the are still printing it, or they are goning out back to cut down the tree to make the paper!

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B Turner wrote "Wonder if you've got 3/8 chains on a trashed .325 drive." all I can see on the chain is Stihl on the cutting links, and a single number 3 on some of the drive teeth (that would go on the worn out sprocket)


Do you think it is neccasary to replace the bar?

Thanks!!!!

Shawn

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[BC_Logger]

replace the sproket and chains, your breaking chains because that sproket should have been changed long ago.

As for the bar try the new chains on it , if there sloppy ( wiggle side to side quite a bit ) change it.



p.s if you change the bar dont throw it out, make a chain sharpening jig

 

[Former Saw Builder]

Put a new rim and drum on it then it will be cheap and easy to change just the rim in the future also replace the bar and chain. you could probably recoup a few dollars for the old bar and chain on ebay...

 

[BC_Logger]

Put a new rim and drum on it then it will be cheap and easy to change just the rim in the future also replace the bar and chain. you could probably recoup a few dollars for the old bar and chain on ebay...

why would you sell a worn out chain and possily a worn out bar to some one

:monkey:

 

[l2edneck]

First off definitly replace all the cutting components (sprocket.bar,chain)



Notice the wear in the link above the rivet from filing.I broke a few chains due to the file removing the metal and reducing the integrity of the link.Combined with the sprocket jerking it could be why they are breaking.
Just a lil tip i learned the hard way......

 

[nilzlofgren]

The last time I used this saw I had sharpened the chain just before,

What did you sharpen your chain with, a 41/2" angle grinder? :hmm3grin2orange: There are no cutters left

 

[7ShawnT]

Where chains are breaking

l2edneck you wrote . . . "First off definitly replace all the cutting components (sprocket.bar,chain)



Notice the wear in the link above the rivet from filing.I broke a few chains due to the file removing the metal and reducing the integrity of the link.Combined with the sprocket jerking it could be why they are breaking.
Just a lil tip i learned the hard way......


Yes, I see there is a small amount of wear from my sloppy sharpening, but the chains seem to breaking at the bottom, or at-least not up near the top, and not at the link that would be affected by "aggressive sharpening" I agree that the sprocket is not helping any!

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Nilzlofgren wrote . . . "What did you sharpen your chain with, a 41/2" angle grinder? There are no cutters left"

I use a hand file, and it still seemed to cut fine.

More pictures . . .
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[jhellwig]

Looks like the rakers are files awfully far down. Make sure the crank isn't bent. Replace the bar sprocket and chain.