close call-heads up

[TheKid]

almost done with the day when i was climbing, removing a small (3.5") stub from a catalpa tree prune job when the chain broke on the 200t. it seemed to break (happened so fast) at the top of the bar at high revs and proceeded to snap back at me whipping the under and backside of my left bicep. I was wearing 3 thermal shirts and it didn't break through any of them but kinda stung for a bit. i was fortunately positioned with my body to the side so my face wasn't in line with the chain. this is the 3rd chain that's broken on me in a year's time and it makes me wonder... what is the max amount of time a chain should be in use? all 3 chains had been re-ground a number of times by my boss (how many, i don't know), leading me to believe there should perhaps be a set number of times to use and grind a chain and then it should be thrown out. the other 2 times the chain broke i was on the ground, bucking wood. be safe all.

 

[treemandan]

almost done with the day when i was climbing, removing a small (3.5") stub from a catalpa tree prune job when the chain broke on the 200t. it seemed to break (happened so fast) at the top of the bar at high revs and proceeded to snap back at me whipping the under and backside of my left bicep. I was wearing 3 thermal shirts and it didn't break through any of them but kinda stung for a bit. i was fortunately positioned with my body to the side so my face wasn't in line with the chain. this is the 3rd chain that's broken on me in a year's time and it makes me wonder... what is the max amount of time a chain should be in use? all 3 chains had been re-ground a number of times by my boss (how many, i don't know), leading me to believe there should perhaps be a set number of times to use and grind a chain and then it should be thrown out. the other 2 times the chain broke i was on the ground, bucking wood. be safe all.

When the chains on them saws get to 50% I throw them out. I always sharpen the top handle chains personally and by hand. The bigger ones I send out but still only take at least a 50% new chain up a tree on any saw. It was one of those things that led me to be self employed where I don't have to argue with my boss about it. Forget it, I am not reving a piece of wasted steel in front of my face, neither should you. I also make sure all chain catching apparattus is ok. So far everytime the chain either broke or has just come off it has been stopped by the catchers. I also freak out when someone walks in front of a big saw running on the ground.

 

[2FatGuys]

I agree with the EXTREME caution around bar tips. I have had several break over the years with differing results. The one thing I know is that any time we have a saw running, I am instinctively checking for clearance in line with the bar, in front of and behind. I would hate to have someone standing in front of the bar when a chain breaks on the top side of the bar on my 394! Also, I push my co-climber to be SURE that he has clear chain path any time he has a saw in the tree. Sometimes even experienced people don't think of the small things. It seems we all want "more power" out of our saws. More power = more danger. PLEASE make sure that you have proper clearance in line with the bar at all times!

 

[oldirty]

all 3 chains had been re-ground a number of times by my boss (how many, i don't know), leading me to believe there should perhaps be a set number of times to use and grind a chain and then it should be thrown out. the other 2 times the chain broke i was on the ground, bucking wood. be safe all.

man i think your guy is digging into the links too deep and weakening them.

not cool. your going to have to keep an eye on them chains man.


you gotta see the light of hand sharpening your climber. that way you are getting an intimate look at the chain itself.

personally i dont let any one else sharpen any thing i cut with. no thanks.


stay safe

 

[clearance]

I have had chains break on me. I have also filed way into the link straps on chains but they have not broken there, and I was suprised. A while back, 'nother outfit, 'nother time, we had 020 chains break on us a few times in a couple of weeks. Culprit=guy making chains didn't care, didn't pay attention to what he was doing.

I file my own by hand, I use saws other guys file, but only some guys.

 

[beaverb01]

2nd that..

man i think your guy is digging into the links too deep and weakening them.

not cool. your going to have to keep an eye on them chains man.


you gotta see the light of hand sharpening your climber. that way you are getting an intimate look at the chain itself.

personally i don't let any one else sharpen any thing i cut with. no thanks.


stay safe

This was the first thing that came to mind for me. When sharpening with a grinder, you have to be extremely careful of the links. Sounds like the boss man is hitting them and creating a weakness that ends up in failure and a hazard to the user.
Inspect those chains and if this is the case, let 'em know! :greenchainsaw:

Beaver

 

[beowulf343]

man i think your guy is digging into the links too deep and weakening them.

I'll agree with this. Have seen it done by guys who get carried away with a grinder.



I don't agree with only sharpening a chain to 50%. Heck, i'll file mine right down to nubbins. File the TEETH properly, and i don't see much need to worry about chain breakage. Like clearance said, most chain breakage we see around here is when the chain is new and it was made poorly.

 

[TheKid]

the last 3 that broke on me, broke at the link plate. boss man is pretty fastidious, and I didn't SEE any evidence of overdoing it with the grinder ( i think he uses a nice oregon bench type). perhaps they have just made too many rpm's. everything has to crap out sometime. if we had a shop where i could, you BET I would grind my own chains. but we don't.

 

[Mad Professor]

Has he been replacing the drive sprocket every few chains he goes through too?

 

[TheKid]

great question mad professor. i don't think so. when I was a bike mechanic, any time a new chain was needed (on modern, moderately expensive[real] bikes) we had to definitely replace the rear cassette and usually the chainrings too. small tolerances gotta be mated.

 

[ronnyb]

In 20 years, I've had maybe 2 chains break. Sounds like you are sharpening down too much instead of pulling back and up into the tooth. Get a sharpening guide if you are sharpening by hand.

 

[00chris85]

i would be asking the questions
-dose your boss make his own chains
cuz if the links are done worng that cause it to fail
or
-your over tighting your chain on your saw
just my 2 cents

 

[joesawer]

Most chains that I have had break are from very high shock loads caused by kick back or more often the chatter that happens when kick back is contained inside a bore cut. The chain usually does not fail at the moment of the chatter but the very high loads crack the steel and it fails later.
I use square chisel, so all my tie straps get ground into pretty deep, and I can almost always link chain failure to excessive shock loads. The chain almost never fails at the point where it is ground, but in the narrow part of the tie links in between the cutters. Usually it fails on one side and I will notice it before both sides break and it flies off the saw.

 

[randyg]

the last 3 that broke on me, broke at the link plate. .

And therein lies the problem sir. Probably a little aggressive with the spinner on one or both rivets. That will make pivot stiff. I've heard many say that after a few revs that will loosen right up, not always true. If chain is oiling well, not just the tang in the bar slot gets oiled but each rivet pivot also. If tight rivet gets oiled quickly on, it will stay stiff. If tight rivet does not get oil for a bit, then the metal will gall and pivot will indeed loosen up but now the integrity of that link has been comprimised, leading to connecting link failure. The one that gets oil quickly stays stiff, and will cause vibration/chatter esp. when bore cutting, thus shock loading entire chain causing failure/cracking throughout.

With saw not running, pinching chain on top of bar near power head and pulling to end of bar, you can actually FEEL a little resistance when that link bends around nose sprocket, and then you FEEL a little greater resistance when that link rounds the drive sprocket (smaller radius).

And that's my two cents

 

[randyg]

I meant to specify, if the connecting links are failing, it is the maker of the loops who is at fault, and not the sharpener. Could be inferior connecting links? (Exception to every rule donchaknow)

 

[Themadd1]

Make sure you are using the proper chain for your bar. .5 gauge in a .58 bar might cause some of the problem? Just a thought.

Also, tightening the chain too tight on the bar can cause excessive wear on the drive links. Heat = failure.

One more thing to check is that your oiler is working properly. There is a book with every chainsaw on the market. Find it and read it, you might find some useful tips in that thing.

I have seen shock load on branches cause damage to chains as well, right as the branch breaks it can catch a tooth, causing it to grab, this can be a problem. Just make sure you have good control of your saw and keep your cutting plane in line with the cut as the branch bends over. I have had chunks of wood catch and wedge into the drive links on occasion. Never breaking a chain but making me stop to take out the wood.

I use my own saw because I know where it has been and what has been done to it. Most companies if they dont require you to have your own saw at least let you use the same saw while you are onsite. That way you know where the saw has been. Also, if you maintain your own saw and do the work on it yourself you gain more respect for the equipment.