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What causes a guide bar to chip bits off near the sprocket?

altair

altair

ArboristSite Operative
Joined
May 5, 2012
Messages
273
Location
New Zealand
My Oleo Mac GS650 is chipping tiny bits of bar off just above and behind the sprocket. After a few hours use today, it left a jagged bit ready to chip off.
I keep my chains tensioned okay, not too tight, but able to be turned by hand, use proper bar lube, and keep the bar clean, by cleaning groove/oil hole etc each day. I'm a maintenance freak.

Cut soft woods only, keep my chains sharp and saw well tuned. Been using saws for 35 years and self employed some of that so pretty good with them. Have never come across this chipping before.

My "hope" is its because its a chinese bar, Zomax brand. Are the chinese bars known for this? Crap metal?

The 661 does not do this, mind you it has Stihl bars.

Will be ordering Oregon or Carlton bars as I have two of these chinese ones, and the second bar has just developed a sticky sprocket, so it went in the bin. Haven't done much work either.

Oleo Mac bars here are crazy expensive. Why I went with the chinese, could get a 20 inch bar and chain for $70, Oregon is $160 NZ.

Crappy bars? Interested to see what you guys think, can't find anything on the net about it,

Cheers
 
Bwildered

Bwildered

Tree Freak
Joined
May 26, 2015
Messages
10,197
Location
33' South
My Oleo Mac GS650 is chipping tiny bits of bar off just above and behind the sprocket. After a few hours use today, it left a jagged bit ready to chip off.
I keep my chains tensioned okay, not too tight, but able to be turned by hand, use proper bar lube, and keep the bar clean, by cleaning groove/oil hole etc each day. I'm a maintenance freak.

Cut soft woods only, keep my chains sharp and saw well tuned. Been using saws for 35 years and self employed some of that so pretty good with them. Have never come across this chipping before.

My "hope" is its because its a chinese bar, Zomax brand. Are the chinese bars known for this? Crap metal?

The 661 does not do this, mind you it has Stihl bars.

Will be ordering Oregon or Carlton bars as I have two of these chinese ones, and the second bar has just developed a sticky sprocket, so it went in the bin. Haven't done much work either.

Oleo Mac bars here are crazy expensive. Why I went with the chinese, could get a 20 inch bar and chain for $70, Oregon is $160 NZ.

Crappy bars? Interested to see what you guys think, can't find anything on the net about it,

Cheers
I've got a Stihl bar that did that, it chipped out so much it derailed the chain really easily depending on which side the bar was flipped, it ended giving me the shites, so it's hanging on a nail in the shed now .
 
Franny K

Franny K

xyz
Joined
Jan 16, 2013
Messages
2,538
Location
North eastern Ct USA
Above and behind the sprocket seems a bit odd. I find coming off the sprocket either drive or nose the chain tends to want to continue in a circular direction and slams into the bar. This often causes chipping or wear of some sort. Another thing is there is a desired set off that the sliding surfaces of the tie straps (and cutters) should be offset from the nose surface as they ride the points of the nose sprocket. Perhaps the actual nose radius is more designed for a different pitch and nose tooth count. I have found this with an Oregon 1/4 inch pitch 10 tooth nose sprocket bar that the bar nose was really for 3/8lp 7 tooth, a more common choice. Oregon even puts out literature that they clearly did not follow in this case.
 
LoveStihlQuality

LoveStihlQuality

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Indianapolis
Why hang on to it? Recycle with scap metal.
I've got a Stihl bar that did that, it chipped out so much it derailed the chain really easily depending on which side the bar was flipped, it ended giving me the shites, so it's hanging on a nail in the shed now .
Sent from my SM-N900P using Tapatalk
 
Franny K

Franny K

xyz
Joined
Jan 16, 2013
Messages
2,538
Location
North eastern Ct USA
If one is going to go to the trouble of taking the chain off to file it in a vice I would want a new bar or section of bar in the vice. That way the drive links and hence the cutters will be closer to rigid.

I have not yet modified bars with the welder but it would seem pretty easy to weld on a section from a hard nose bar or a nose intended to be riveted on.
 
Big_Wood

Big_Wood

westcoast dweller
Joined
Dec 11, 2012
Messages
7,335
Location
Canuckistan
If one is going to go to the trouble of taking the chain off to file it in a vice I would want a new bar or section of bar in the vice. That way the drive links and hence the cutters will be closer to rigid.

I have not yet modified bars with the welder but it would seem pretty easy to weld on a section from a hard nose bar or a nose intended to be riveted on.
I’ve welded on a bunch of bars to repair rails and even had them last. To weld sections of bars to other bars might call for a new bar though lol This issue is sounding like a chain to loose and in potential need of help. When cutting with bottom of bar any looseness in the chain will chatter just before the tip on top especially if a guy is trying to force a dull chain to cut. While back barring the chatter moves to the top of the bar tail. Why so many go through so many bars.
 
smokey7

smokey7

jack of a lot ace of a few
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Sep 22, 2014
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As far as good cheaper bars stay away from the Forester green label bars. The red label Forester seem just a little better then there are Forester pro which are comparable to Oregon Powermatch. My new favorite bar is the Forester Platinum bar. I bought a 24" d009 3/8 .050 with a loop of there full chisle chain for real close to 40 shipped. I would say its neck and neck with Sugihara quality wise. Ive now wore out 3 chains and have absolutely no wear atall on the rails or sprocket. Forester touts a rockwell hardness of 58 on the rails in the adds ive seen and its 58 in the center of my bar and 60-62 at the rails. The green Foresters are low 40s rockwell the red is mid to high 40s the Professional Forester and Oregon are high 40s to mid 50s depending where you check. Now for about $40 us where or what kindabar and chain can you get for that kindof money. Ive seen Hutzl bar and chain combos going for near that and are nowhere near the quality of Sugihara or Forester Platinum. Im so pleased with my Platinum bar im telling everyone i can. I used to be a loyal GB bar and a ton of chain guy till the chain went to hell and the bars got to almost double the cost of what i was payimg for them. Oh and my GB TItanium bars are 55-57 hard but seem to like to chip to right behind the tip\bar seam.
 
Mike Kunte

Mike Kunte

ArboristSite Operative
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Aug 15, 2017
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The main cause for this is a chain which is too loose. I've been cutting for nearly 20 years (without chipping bars near the srpocket), and just last week met "Mr. Chainsaw", Marius Taljard, who showed me that my chains were too loose. He tightened my chain up to where I thought it was waaaaaaay too tight, yet it turned out to be perfect! No sagging after working with it! Sooooo, long story short - even though I have not had damage to bars from loose chains, my "tight" were still too loose....
As long as you are running a sprocket tip as opposed to a solid tip, you can really tighten that chain up!!!

But having read your post again, it probably has something to do with the Chinese metallurgy of the bar..... Best to replace it with the proper item...
 
thomasinvancouver

thomasinvancouver

ArboristSite Member
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Apr 19, 2018
Messages
79
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Vancouver, WA
What’s the distance between the sprocket and tail? Is the tensioner maxed out? This will cause the chain to impact the bar and results in increased heel wear. Could also be a poor quality bar or a combination of both.
 
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