Harvester Chain 3/4 cutters breaking.

[c greenham]

Hi All,

Having issues with the saw chain cutters breaking on the bottom side of the saw chain. 

Any one have experience with this and have suggestions of a possible correction.

Thanks for your help.

[Gary_C]

Any pictures? I'm not sure what you mean by the "bottom side."

You should look for a bad nose sprocket, a pinched groove or misalignment with the bar mount.

Most large heads that use the 3/4 pitch chain have enough power to rip a chain apart if the chain is binding anywhere. Find out where the binding occurs.

[c greenham]

The bottom side means, lower side of the chain towards the saw box bottom.

The saw drive sprocket is worn but the cutter bar nose is good.

[BargeMonkey]

How many teeth are you breaking off ? How worn is the chain you've broken them off ? I've done it before, noticed more on the "bottom side", always chocked it up to a rock or tougher wood. Are you knocking your drags way down ? Chattering in wood ? 

[c greenham]

The chain is almost new about 8 cords on it, four cutters broken on one side.

The wood is all soft wood fir and spruce.  I'm wondering if its hitting the saw box but it doesn't appear to be as I cannot see any marks.

Would misalignment between the chain and the sprocket cause this issue?  It looks like the tip of the cutter bar is closer to the saw box then the sprocket end.


Thanks for the help.

[moodnacreek]

Saw chains, files and bandsaw bands from time to time are hardened wrong. I can remember my first mini chainsaw, the o.e.m. chains broke off the cutters. The dealer told me I hit something like i didn't know. As a teenager I had cut more wood than him.  Whatever the problem it will be on you.

[barbender]

I've experienced faulty. 404 sawchain that kept snapping side plates. Ponsse knew it was a bad batch of chain (Oregon) because other operators were experiencing the same thing.

 There's a lot more meat in a 3/4" chain but I suppose if they are over hardened they would do the same thing.

[Firewoodjoe]

I ran my sprocket until the chain skipped. It wouldn't cut hardwood anymore.

I've hit my saw box, dirt, rocks bent bars sparks fly all the time.

My original saw arm had been repaired so it was weak. It would bend all the time in big hardwood. I'd run the saw out , chain spinning and bend it back on a stump. While the chain was spinning! Did that for over a year then bought a new saw arm.  

I've had bars bent and pinched to where it was smoking and throwing sparks and just ran it until it stopped.
Yes I'm crude and these bars and chains take it.

My point is when I say these are tough they are tough. Crazy tough. The only time I have a chain break is 1) when it gets bent. Either it breaks then or when I try to bend it back.
2) when the chain is just old. They get worn and weak before you'll ever wear the teeth out. At least in my case. Lots of hardwood. In about 16 months I'm on about 20 chains and 6 bars. I've bent and rebent all my bars. I never get them perfect and they still cut a full 24" just fine.  I still use all but one chain. It's missing so many teeth and is about half sharpened down I just keep it for a spare.

Pull your bar out with a chain on. Eye ball down it from the sprocket side. If it's pretty straight it will work. Then I'd put another new chain on. Out of the Oregon bag. Not one someone is making. Then run it for just a few cuts stop take it off and look for hotspots on the chain or the bar. And marks on the side of the tooth. That will tell you if it's hitting something but you should see that easy without cutting anything.  If none, run it again. But I would fell a large pile if you can. Then process out of that pile so you can try to verify if it's when felling or bucking. Good luck.

[c greenham]

Hi Firewood Joe,

The chain will always break during the falling process, this wood I'm cutting is small softwood. It seems if there is any brush in the way it will knock the chain off or cause it to bend. 


Thanks for your help.

[barbender]

If it is getting knocked off by brush it is probably getting kinked.

[Firewoodjoe]

Hi Firewood Joe,

The chain will always break during the falling process, this wood I'm cutting is small softwood. It seems if there is any brush in the way it will knock the chain off or cause it to bend.


Thanks for your help.

Ok. If I remember somewhere you posted about your chain being loose. I wonder if your block needs resealed to maintain more tension. This isn't right and may not work in your case but one time a fixed a chain and made it one link to short. 54 rather than 55 drives.  It went on but hard. You could try that and that will take up a lot of the slop. These things will fly off easy if it's spinning with a twig pushing on the chain. But either way it must be getting bent to break. Chains fly off and don't generally break when they do. 

[Firewoodjoe]

I just looked at the pic in your gallery and it is bent some but should work. I've had mine hitting the tip on the saw box and never broke or threw chains. 

[Riwaka]

The Logmax head (in the pic) (and other processing heads) has holes behind the drive sprocket to let the sawdust out so the sawdust does not build up in the saw park enclosure.

https://www.logmax.com/en/products/4000t/

[c greenham]

Hi All,

I'm thinking that maybe the sawdust, twigs will build up in the saw box and cause the chain to bend and break.  

Will try to keep the sawdust hole clean I wasn't thinking about that, we have about 16 inches of heavy snow in this area now.

The chain drive link was split in the middle this time were it was previously bent.  

Logging is a learning curve for sure. 

Thanks for all your help.

[Skeans1]

We've had a whole saw box plugged full and I can't think of one time it has caused cutters to break unless there's a rock in there. There's a couple of bearings that I can think of that might cause this, one a saw motor bearing, a sprocket nose bearing on the bar and the bearing as well as the wear plate for the saw  bar mount that can cause something like this to happen. If I remember correctly this is a manual adjuster one still if it is I'd check the bar tip then the motor shaft if you're not loosing it off at the end of the running day it will take them out.

[BargeMonkey]

 I don't wanna hijack his thread but if we are on the subject of 4-rollers,
 Do they measure close enough with the just the regular wheels or is the inner 3rd wheel mandatory? Any idea how bad it is to install ? 

[Firewoodjoe]

Saw box plugged up won't cause anything except sometimes the saw sensor won't read home. But a sapling at the base of your trees will push on your chain and cause it to come off. But it needs to be a stout one. But still shouldn't break often. 

[Firewoodjoe]

I don't wanna hijack his thread but if we are on the subject of 4-rollers,
Do they measure close enough with the just the regular wheels or is the inner 3rd wheel mandatory? Any idea how bad it is to install ?

All I know is there's a lot of 4 rollers here. And everyone disconnect or shut off the wheel encoders. Ive heard they need to be calibrated or something also. 🤷‍♂️ Fabtek themselves must have thought it needed a third wheel. 

[c greenham]

Good day all,

Update put on a new chain on last evening ran it for a few hours no issue, I'm thinking that the small brush knocks it off and the chain gets kinked then breaks.  Somehow the teeth gets broken but not sure how.  Maybe it was a faulty chain.  I'm being very carful on the head placement and positioning trying not to tilt head to to far forward to keep it from hitting a rock.  I'm in Newfoundland Canada rocks are everywhere .

I don't have the encoder hooked up on the unit it came disconnected, I just measure the first log and cut the rest to match, I cut everything 8 ft long.  At some point if I get the chain issue straighten out I will see how to hook up the measuring system, its all there but unplugged according to the guy I bought it off.

Thanks for all your help.

[c greenham]

Just an update on the 3/4 chain issue, I put on a new chain if I tighten up the chain when the bar is out to the required specs the chain will break after a few trees are cut.  If I leave it lose so that the drive links are barely in the bar guide it last much longer.  

Still breaking teeth on one side of the chain cant figure out why.  Not cutting any hardwood and the ground is good with no rocks keeping my stumps a bit high to avoid hitting the ground but still breaking teeth.

[c greenham]

Hi All,

Kinked another chain this week this time the chain didn't come off during the process, it seems as if once the cut is finished and the saw button is released the chain spins backward during the bar retraction.  This is when the chain runs of the bar and kinks, this time when trying to get off the bar nose sprocket the chain kinked.

The sprocket nose seems to be worn and sloppy, I have installed a new nose of the cutter bar also I made a bar mounting pad to be placed near the drive sprocket.  The pad is a little wider then the bar the hope is it will prevent the chain from spinning of during the bar retraction.

Will try it out this weekend to see if it works.


 Merry Christmas Everyone.

[Skeans1]

Under the sprocket is there a spool?

[c greenham]

Just a bolt and washer holding on the sprocket no spool. 

[c greenham]

 

 

 

 

[Skeans1]

The spool on the bottom helps keep the chain from getting tossed in the brush. Now that plate is no where near as thick as what was once there, my head says it was 1" solid aluminum with counter sunk holes for the nuts to protrude from. When everything is in the right place and together I don't remember being able to use a 1/2" racket with the thicker head to be able to tighten or loosen the bar nuts.