Chain failure

ColdColdCutter · October 03, 2020, 07:55:49 PM

I never had a chain break on me in my whole life, but just had 2 chains break on me in 2 days... (Stihl Pro 74 on a 261C).

Inspected the bar, and I could see some burs rolling outwards, and it kinda looked like the chain dug a line into the bar.

Any idea of what could be the cause?
Chain too tight? Wrong chain? (chain came with the saw)

lxskllr · October 03, 2020, 08:03:11 PM

Check everything out. Make sure the bar groove isn't too sloppy. Check the drive sprocket to make sure it isn't worn too far. Make sure gauge and pitch of the chain are correct for your bar/sprocket. Look at the chain. Perhaps it was a homespun job, and the guy didn't do a good job setting the rivets.

Southside · October 03, 2020, 08:46:42 PM

Never broke a saw chain, but have broken multiple ones on 3/4" harvester chain, like lxskllr said usually it's the non factory rivet that gives way.

Mad Professor · October 03, 2020, 10:58:30 PM

Not sure what you mean by Stihl pro 74?

I think most 261 came with stihl 0.325 pitch, 0.063 gauge chain. So would be a variant of 26 RS or 26 RM chain or equivalent. Bar should be marked for gauge/pitch. Do they match up?

Sounds like the bar has some wear and needs to be dressed. Got a picture(s) of bar, chain , and drive sprocket?

realzed · October 04, 2020, 12:08:15 AM

Maybe its one of those new 23 RS Pro chains.. .325" / .050" - Stihl #3690 002 0062 (# for a 16" bar) types?
Wouldn't imagine they would be 'made up' or versions..
In Canada at least as far as I know, all 261's always only come in .050" bar gauge size.
Maybe he has .050" gauge chain on a .063" bar and that's why it seems to be digging into the rails?

sawguy21 · October 04, 2020, 01:45:54 AM

The Pro series is the new narrow kerf, similar to Oregon 95VP. 74 is the drive link count. I too wonder if the failed chains were improperly spliced by the dealer.

Mad Professor · October 04, 2020, 02:54:56 AM

Quote from: realzed on October 04, 2020, 12:08:15 AM
Maybe its one of those new 23 RS Pro chains.. .325" / .050" - Stihl #3690 002 0062 (# for a 16" bar) types?
Wouldn't imagine they would be 'made up' or versions..
In Canada at least as far as I know, all 261's always only come in .050" bar gauge size.
Maybe he has .050" gauge chain on a .063" bar and that's why it seems to be digging in to the rails?

Is the OP in Canada? In USA the 23 RS chains are not available nor are the bars that fit them. Every thing is .325/0.063 (unless you go picco or 3/8 ) I'd like to try those on my 50cc stihls, but I've got a stash 26 RS/26 RM chains and bars are all 0.063.
P.S. is the camaro in your avatar yours? I've got a 68 RS/SS

realzed · October 04, 2020, 03:33:19 AM

Yes it is - or was.. 'born with' Z2/8 all original, that I sold almost a year ago now.
Had it for over 30 years but hardly ever used it in the last 10 or 12 years.
Wife called it 'The Red Paperweight' as all it did was sit parked in the garage.
Went as far West in Canada as possible (Vancouver Island) and as much as I thought I would, I don't really miss it anymore!
Need to change my picture I guess..

lxskllr · October 04, 2020, 05:46:18 AM

Quote from: Mad Professor on October 04, 2020, 02:54:56 AM(unless you go picco or 3/8 ) I'd like to try those on my 50cc stihls,

I just picked up an 026, and the .325/.063 is an odd setup for my system. I'm thinking I may want to go to 3/8lp. The sprocket should be easy enough, but what to do about the bar? The dealer said Stihl doesn't make anything that fits. Got any suggestions? I have a PoulanPro beater bar I'm gonna compare to, and see if it can be modified. If so, that would open up a whole range of options. I may not even do anything. I might love .325, and this saw isn't a primary anyway, but it would be nice to keep everything in my existing supply system.

Mad Professor · October 04, 2020, 11:18:00 AM

Quote from: lxskllr on October 04, 2020, 05:46:18 AM
Quote from: Mad Professor on October 04, 2020, 02:54:56 AM(unless you go picco or 3/8 ) I'd like to try those on my 50cc stihls,

I just picked up an 026, and the .325/.063 is an odd setup for my system. I'm thinking I may want to go to 3/8lp. The sprocket should be easy enough, but what to do about the bar? The dealer said Stihl doesn't make anything that fits. Got any suggestions? I have a PoulanPro beater bar I'm gonna compare to, and see if it can be modified. If so, that would open up a whole range of options. I may not even do anything. I might love .325, and this saw isn't a primary anyway, but it would be nice to keep everything in my existing supply system.

Stihl made their E bars with the 3003 mount, but they are hard to find in USA. Probably a lawyer thing with guys using picco chain for milling with a 066, that's what I do with the 63 PMX chain.
I know GB made some picco bars with the 3003 mount but they are not listed on their website. Have have one in 25".
Try to contact a Logosol distributor, they deal in the 63 PMX chain and picco 3003 mount bars. Fox Forestry is much better to deal with compared to Bailey's 1 (207)667-6703

Tacotodd · October 05, 2020, 01:54:29 PM

Folks, we're just assuming that the riveting let go. Now, I've never seen or heard of this, but it's possible a connector link has let go. Don't get me wrong that this scenario is very improbable, but do to rusting and improper storage of the chain and/or saw, and/or combined with extreme usage prior to this occasion that it would be enough to cause this.

I'm not saying that this is what happened, but without CCC's further elaboration, anything is possible, however improbable.

Just food for thought.

ColdColdCutter · October 08, 2020, 01:40:03 AM

I am canadian! All the specs seem to line up between the bar and the chain, and everything was factory, with very little use (less than 150hrs) heres the bar and chain used, and what the chain looked like after. One of them actually broke in half, and I never found the other half.
I have no picture of the bar before I filed it back to normal.

The service guy said that the bar damage was due to loose chain, but that seems very unlikely, since I kept it very tight (was cutting lots of branches and saplings)

br>

Real1shepherd · October 08, 2020, 10:29:27 AM

Well the good news is historically, at least, this is extremely rare in occurrence. In all the thousands of hrs with pro saws and pro chains I've never had a chain let go. You always think about it and are conscious of it, but it rarely happens. I'd hate to think that companies who make chain for weekend warriors and firewood gatherers are cheapening their product based on the amount of continuous use it may get.

If anything, you'd think the chain manufacturing companies would not want the liability....and that alone would keep them honest. But if chain is now being made in China, that's a whole other can of worms.

Kevin

realzed · October 08, 2020, 03:54:22 PM

Did I miss something and Stihl chains are possibly now being made 'off shore' or is that just an wild assumption you are making?
It is unusual to have one break - let alone 2 granted, and it does make one consider that something possibly has changed in the production of the chains Stihl sells - but it's pretty hard to make the leap that a German company would source out any production at all to China or any other Asian country considering the well known German mentality for quality, durability, and brand consciousness..
I too have a brand new and still in the box 23RS Pro chain - and this has me wondering about trying it out personally - I'll wait and listen in to see if this seems to be somewhat of an known issue before I throw it on and give it a whirl though..
When this sort of thing does happen for whatever reason - does a broken chain link or rivet usually present a real dangerous situation because it wildly flings around or does a break usually just result in it falling off the bar or binding in the cut?

lxskllr · October 08, 2020, 04:05:00 PM

AFAIK, all Stihl chain is made in Switzerland. All my boxes are marked as such. Just got a 100' of pm chain last week; Swiss made.

I've never seen a chain break. I'm not out cutting every day or anything, but I've put some gnarly stuff, on some gnarly bars and haven't had an issue. For the OP, carefully inspect all your gear, make sure it's within tolerance. Pay particular attention to the bar. Make sure the grooves aren't wallowed out, the rails are true, and the sprocket spins freely, Then try a brand new chain. Don't tighten it too much on the bar. It shouldn't cause it to break, but it's hard on the saw.

trapper · October 08, 2020, 10:24:25 PM

My dealer makes mine off the reel and I have never had a problem. I run them until they are down to the mark on the back of the cutter. Some even farther.

barbender · October 08, 2020, 10:38:08 PM

I've broken many chains in a harvester, it was a known issue that Oregon had with their harvester chain for a bit. I don't know if they were incorrectly heat treated or what, that's what I suspected. Kept snapping drivers on brand new chains, just like the OP's pictures. I've read on the forum of batches of chain that the cutters were tempered too hard so a file couldn't cut them, if that happened to your drivers they would likely break. I'd try stroking a file across that broken driver and see if it will cut it. If not, I think you've found your problem.

Real1shepherd · October 09, 2020, 10:20:39 AM

Quote from: realzed on October 08, 2020, 03:54:22 PM
Did I miss something and Stihl chains are possibly now being made 'off shore' or is that just an wild assumption you are making?
It is unusual to have one break - let alone 2 granted, and it does make one consider that something possibly has changed in the production of the chains Stihl sells - but it's pretty hard to make the leap that a German company would source out any production at all to China or any other Asian country considering the well known German mentality for quality, durability, and brand consciousness..
I too have a brand new and still in the box 23RS Pro chain - and this has me wondering about trying it out personally - I'll wait and listen in to see if this seems to be somewhat of an known issue before I throw it on and give it a whirl though..
When this sort of thing does happen for whatever reason - does a broken chain link or rivet usually present a real dangerous situation because it wildly flings around or does a break usually just result in it falling off the bar or binding in the cut?

I don't know how you made that leap about Stihl chain to Chinesium. No "wild assumption" or rumors. I was talking about ALL chain manufacturing in general, not Stihl. And I don't know if any chain is made in China yet....I was saying IF chain was made in China.

Kevin

sawguy21 · October 09, 2020, 11:51:11 AM

Offshore chain is being sold in North America, I have seen some forum posts asking about it. One here but the poster disappeared. I googled the brand he asked about, apparently it was known to break.