Stihl chains snapped

[lefturnfreek]

Here's a few pic's of a Stilh 325 I did in today...



There were 8 cracked single links, 2 double cracked links





and a piece missing from another...




This was a new chain and rim not too long ago, hasn't hit anything hard or tripped the chain brake, no plunge cuts....it's not worn to the rivets, only half way through the tooth length and maybe the rakers were done twice, I can't wait to swap this saw to 3/8ths cause I'm not impressed with tier 325. I have only broken 1, 3/8ths chain in the last few...10.. years and that was my fault, way tougher stuff.

 

[HarleyT]

Wow!!!! Nasty abuse on the bottom of those tie straps!!!! What does that poor bar look like??? You putting your full weight on the saw in the cut because the rakers are too high?

 

[CR888]

^^^Hooray!! A picture tells many words and all these chain pics really explain far more than 'manafactoring faults'. Look closely at the peened bottoms of the tie straps/cutters and nearly all pics show a chain/bar/sprocket setup that is not working as it should. Also have a look at the drive tangs and what condittion/wear they have. They should be sharp/pointy. lnitially before closely looking at the right bits of the pics l thought this thread was probably about a faulty chain, big deal. Stihl sell millions of feet of chain and most of us would agree its consistantly pretty good, up there with the best. l believe under close examination nearly all these cases are due to excessive wear from tight chains, low rakers, worn sprockets, to much hook, ect. When you think about it l am surprised we don't hear of more failures with chain.

 

[lefturnfreek]

Wow!!!! Nasty abuse on the bottom of those tie straps!!!! What does that poor bar look like??? You putting your full weight on the saw in the cut because the rakers are too high?

^^^Hooray!! A picture tells many words and all these chain pics really explain far more than 'manafactoring faults'. Look closely at the peened bottoms of the tie straps/cutters and nearly all pics show a chain/bar/sprocket setup that is not working as it should. Also have a look at the drive tangs and what condittion/wear they have. They should be sharp/pointy. lnitially before closely looking at the right bits of the pics l thought this thread was probably about a faulty chain, big deal. Stihl sell millions of feet of chain and most of us would agree its consistantly pretty good, up there with the best. l believe under close examination nearly all these cases are due to excessive wear from tight chains, low rakers, worn sprockets, to much hook, ect. When you think about it l am surprised we don't hear of more failures with chain.

Ahh... abused tie straps??? When you use a rim instead of a spurred drum, that's what they'll look like.

Bar is a 3 chain old Husky 18in, looks just fine, the rails are square, not pitted, not chewed up, not gouged, not burned... and that was the bottom when the chain broke.





No, I am not leaning on the bar, if it doesn't cut with just the weight of the saw or self feed, it's time to sharpen it.

Rakers are set to the hard sided of a Husky guide.

Here's a brand new #3 Stilh 325 chain to compare the drive tangs to, bout the same...I'm using a rim not a spurred sprocket....



Here's the new Power Mate rim that was installed at the same time as the chain, barely worn, as expected and as per usual.





Stihl has changed something in their 325 chain in the last couple years and I don't think towards the good cause I have never broken so many 325 chains, ever.

 

[CR888]

The way a cutter moves through wood is similar to the motion of a dolphin. l see excessive hook on your chain which WILL flatten the rear heel of the cutters and that sprocket looks quite worn for such little use. Service guides usually require spocket replacement if there is .5mm or more wear. That sprocket is past that IMO however l know close up pics can be tricky sometimes. l am not trying to give you a hard time, just trying to help. Did you find that chain a bit 'grabby'. The carlton chain guide (pdf) book l suggest you download and read, its really good at explaining all this with all the reasons why the rear/front cutter heels get worn and why this happens. Download this and give it a read, l think you will maybe change the way you see this.

 

[nmurph]

I don't see anything wrong with either the chain or the rim. The bar definitely has some burring, but I don't think it's anything that would cause a chain to snap.

 

[Knobby57]

The rim does look like a lot of wear for being newer . Something is going on


Sent from my phone when I should be working

 

[HarleyT]

Can we see the writing on the bar and the sprocket? I still think the excessive stress and damage is coming from you leaning into the cut hard due to the high rakers....

 

[lefturnfreek]

The bur on the nose of the bar has been there from brand new and looks way worse in that pic, not from the chain hitting the nose of the bar, the nose sprocket is maybe 5 thou of play, barely decernable difference from new. No burs on the side at all.

Here's the writing you want.




Heals of chains get really hammered from running a loose chain, tooth rolls back under load. If there was slack, it gets tightened when needed and turns freely after, so not over tightened, same way I do for all my saws.


Here is a just a few broken 325 chains just off the top of the scrap metal bin, some are pretty worn, one from a barb wire hit, the rest just broke in use. These are from 5 different saws, 3 different users and chain from different dealers. So this not just me breaking them.





Just to make sure I'm not taking a pic of a different chain, same pic as posted before, look for the red arrow at the bottom, how is that a hammered, worn heal?

Your seeing more than what's there.




If my rim is worn out after only 1 chain, that I didn't even use as far as I thought I should have, what am I going to do? Replace the rim half way through the chain....

That same chain was dismounted and checked over last week for damage as this is not my first rodeo with 325 going flying, none was seen and it was remounted. I put maybe 2 tanks and 1 sharpening since.

Like I said before, I'm not impressed with the new 325.

 

[HarleyT]

We should look at that chisel there closer, because at this view it looks like it is @ an 85 degree cutting angle. With that and untouched depth gauges/rakers helps explain all of that wear/damage. And the actual broke tooth, is probably still with the nail it hit.

 

[lefturnfreek]

What are you looking at??

It's filed to 25, or in your world 65 degrees.

The rakers have been filed, then they have been rounded off, to the hard side of a Husky guide.

There was no nail in the block, the missing piece is gone, it's called a chain shot, do I need to explain that to you also? I took it in the bottom of my jacket and the top of my saw pants. Felt it, never looked for it.

The "hammered" tie straps were only 8 thou thinner, from the bottom of the strap to the top, than a brand new chain.

The "worn out" rim, was only 4 thou

This is getting tiring, answering the same questions over and over again, also petty, but if you absolutely need another pic of that chain, say from the top just to disprove your irrational conjecture