Chain loosening

[Bludenz]

Hey all.

Got one of my project saws together. Put everything back together works sweet. After a few cuts the chain will become very, very loose to the point it is hanging. Chain also gets pretty hot. After some reading, people suggest that excessive wear on the sprocket can cause this. Pictures of my sprocket are attached, could this be my problem?

I've removed the adjuster assembly, cleaned it, re greased it and put it back together, no change. A new sprocket would set me back approx 40usd. What causes this wear on the sprocket, incorrect chain?

Thanks in advance

 

[Franny K]

That sprocket is beyond the wear amount when replacement is sensible. Or called for in user manuals. The chain may be excessively worn as well. Stretch out the chain, then compress it in a straight line and note the difference. Compare to a new one.

 

[Bludenz]

That sprocket is beyond the wear amount when replacement is sensible. Or called for in user manuals. The chain may be excessively worn as well. Stretch out the chain, then compress it in a straight line and note the difference. Compare to a new one.

So a new sprocket is required?

 

[sundance]

So a new sprocket is required?

Yes

 

[Philbert]

That sprocket is worn, but not as bad as many that I see.

Sprockets and bars are consumables, just like chains, or the brakes on your car. They need to get replaced eventually.

Running chains too loose, or too tight, can accelerate sprocket wear. As can running old, worn chains on a new sprocket, or vice versa.

If your chain is getting hot, part of that might be the oiler, or the way it is sharpened.

Philbert

 

[Franny K]

You did not specify what the saw is. I suspect you could get a Stihl mini spline kit instead of an exact replacement. Oregon or generic small spline as well most likely.

 

[Bludenz]

You did not specify what the saw is. I suspect you could get a Stihl mini spline kit instead of an exact replacement. Oregon or generic small spline as well most likely.

Ms192t. I'd prefer oem. No reason other than keeping me happy.

 

[Mad Professor]

Ms192t. I'd prefer oem. No reason other than keeping me happy.

Get a drum that takes rims and change the rim/sprocket every few chains.

Better yet rotate 2-3 new chains on the same new rim to keep the wear even between them.

Any combination between worn out and new, is going to make the new worn out fast

 

[ZeroJunk]

Dull chains are the worst enemy of about every part of a saw.

 

[Bludenz]

So in conclusion, the sprocket is the most likely cause of my chain loosening issues?

If it is, I'll most likely get a new sprocket and a new chain from my nearest stihl dealer. The bar still has some life left in it.

 

[djg james]

As stated, is your oiler properly working? In my limited experience, I've found that when my oiler isn't working, my bar/chain gets hot and the chain actually stretches.

 

[muddy42]

So in conclusion, the sprocket is the most likely cause of my chain loosening issues?

If it is, I'll most likely get a new sprocket and a new chain from my nearest stihl dealer. The bar still has some life left in it.

That's probably what I'd try, bars last longer than sprockets which in turn last longer than chains.

BUT if you think about it, the sprocket, chain and bar nose sprocket teeth are all related by the 'pitch' of the chain and they all wear or stretch together, meaning the pitch gets longer than it should. If there is excessive stretch all three components need replacing at the same time. Just replacing the chain for example means you'll have a miss match and that chain will get worn quickly by clattering on the the mismatched sprocket and teeth.

Its best to check often and be aware of this relationship. But very generally I will replace sprockets after two chains have worn. Bars last must longer and I generally damage then before I wear out the nose sprocket teeth.

 

[Bludenz]

As stated, is your oiler properly working? In my limited experience, I've found that when my oiler isn't working, my bar/chain gets hot and the chain actually stretches.

The oiler does work.

 

[Bludenz]

That's probably what I'd try, bars last longer than sprockets which in turn last longer than chains.

BUT if you think about it, the sprocket, chain and bar nose sprocket teeth are all related by the 'pitch' of the chain and they all wear or stretch together, meaning the pitch gets longer than it should. If there is excessive stretch all three components need replacing at the same time. Just replacing the chain for example means you'll have a miss match and that chain will get worn quickly by clattering on the the mismatched sprocket and teeth.

Its best to check often and be aware of this relationship. But very generally I will replace sprockets after two chains have worn. Bars last must longer and I generally damage then before I wear out the nose sprocket teeth.

Thanks for the advice. I bought this saw used from a New Zealand tree cutter. Those guys are very down to earth. Run it into the ground and sell it. I've got no idea how it was treated or how many chains/bars it's been through.

Sprocket and chain here I can get for about 70usd, bar would be significantly more.

 

[muddy42]

Thanks for the advice. I bought this saw used from a New Zealand tree cutter. Those guys are very down to earth. Run it into the ground and sell it. I've got no idea how it was treated or how many chains/bars it's been through.

Sprocket and chain here I can get for about 70usd, bar would be significantly more.

Id buy a new chain and sprocket then check it runs ok on the bar. Fit the chain and get the tension right then manually turn the chain and dont start it! If it feels bumpy or the chain lifts out of the rail at the nose, you need a new bar aswell.

 

[Bludenz]

Id buy a new chain and sprocket then check it runs ok on the bar. Fit the chain and get the tension right then manually turn the chain and dont start it! If it feels bumpy or the chain lifts out of the rail at the nose, you need a new bar aswell.

Thanks alot man. Appreciate it. You might’ve just saved me 70usd

Hopefully I'll have some time to pop into the stihl dealer tomorrow.

 

[dandan111]

I bought some cheap chains from Amazon. They stretch non stop. I’m always tightening the chain. They do sharpen easy but I’m about ready to toss them. I won’t cheap out on chains again.

 

[barfer]

A worn sprocket will certainly mess up a chain but not as immediately as you describe it. So if your sprocket is worn that’s a separate issue that needs to be addressed as well but like philbert said I instantly thought oiler issue… but you say the oiler works… maybe try oiling it with a bottle the way the mill guys use an auxiliary oiler on their saws… see if you get the same symptoms.

Either way I hope you get it sorted and I’m curious. Good luck and keep us posted!

 

[barfer]

And FWIW based on what I can see in your pics that sprocket doesn’t look super worn to me (shrug)

 

[Bludenz]

And FWIW based on what I can see in your pics that sprocket doesn’t look super worn to me (shrug)

Maybe just the chain is stretching. I can't seem to find the stihl logo on it anywhere... could eb a chibese chain... might just have to buy a new chain and that might fix it.

Edit: nevermind found "stihl" text on it. Assuming it is a stihl chain at this point