Need Help from the "Big Saw" Guys

Jed

TreeHouser
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Nov 2, 2010
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Snoqualmie, WA
Weirdest Thing. We've got this foreman who transferred over here from the Philadelphia office who had never seen or heard of square-grind before. "Why wld you ever use that," he asked. So, after explaining about the straighter and faster cutting bit, I added that, since the top-plate angles are less severe, (about 15 degrees with square, as opposed to some 35 degrees with round) than round grind, the drivers pull much less hard to either side in the bar groove than round, thus minimizing friction, and prolonging the life of the guide bars. "Oh," he said.

Next thing you know the shop gives him a brand new 660. Next thing you know, he tells me that the brand new 32" stock guide bar is "bent, or something, cause it won't cut straight, no matter what I do...." Of course we just accuse him of being a crummy sharpener, but here's the thing: I've always seen that his top-plate angles were very, very good, and consistent, AND, I've always known his saws to cut straight when mine had a broken pull-cord, or whatever.

Anyway, they buy him another brand-new bar, this time a 25", which he actually wanted. East-Coaster, what can I say. The thing runs absolutely perfectly for about two months, and then WHAM. All of the sudden, the darned thing will not go through a log. When you try to dog it around through a big cut, it suddenly just locks up (no burrs at all, believe me: I already thought of that) and will not go farther no matter how hard you lean on that pig.

Any guesses? I'm as stumped as a Cottonwood.

P.S. After saying that he sharpens really well, I WILL tell you that he cuts his side-plates a little too deep, because he really likes that super-aggressive "pull" feeling that the acute "beak" of the side-plate of a round-filed chain will provide.
 
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Of course.... Silly me.

O.k. Does anyone BESIDES BUTCH, have any ideas. :)
 
He may have taken out the gullet of the tooth leaving the top plate to thick as well. When you file down, instead of across they tend to get grabby!
 
Inaccurate cutting can be caused by lots of different things, I go through them in descending order of likelihood. (Probably some iv missed too)

Incorrectly set depth gauges.

Inconsistent sharpening, ie if the technique is different on one side of the chain because of poor technique one side will cut slower.

Burrs or rails on the guide bar.

Loose nose on guide bar.

Last and very rare IMO, slight bend or twist in guide bar.

Many guys jump straight to the last option without considering the other much more likely possibilities. It's really simple to rule out the guide bar, throw a new chain on and if the symptoms disappear then its the chain.

All chain maintenance faults are amplified on long bars, its not uncommon for an inexperienced sawyer to get trouble when they step up to long bars for the first time.
 
Anyway, they buy him another brand-new bar, this time a 25", which he actually wanted. East-Coaster, what can I say. The thing runs absolutely perfectly for about two months, and then WHAM. All of the sudden, the darned thing will not go through a log. When you try to dog it around through a big cut, it suddenly just locks up (no burrs at all, believe me: I already thought of that) and will not go farther no matter how hard you lean on that pig.



P.S. After saying that he sharpens really well, I WILL tell you that he cuts his side-plates a little too deep, because he really likes that super-aggressive "pull" feeling that the acute "beak" of the side-plate of a round-filed chain will provide.
So then it cut fine for a few months then fell down ?

Put a little square on the bar rail and see if one side is worn more than the other which would tilt the chain .

If nothing else grind the chain so you know it's dead right .It has to be one of three things .Either a bent bar,crooked rails or a bad sharpening job .
 
So is this on square chisel or round? I am not sure I got which chain he is actually using at this point Jed.
The gullet is very important on square.
gullet_filing.jpg
 
That's interesting Stephen. I've never left that little shelf on there like that. I do know you can't neglect round filing the gullet, or things will slow down drastically.
 
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Can't thank all of you enough for the generous and thoughtful responses. Also can't wait to go through em all one by one. Slammed at the moment, but I've got to solve this thing.
 
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Rajan: Yup, he hogs his stops down WAY too far, for one thing. "I'm just addicted to that feeling.... like the saw wants to damn near rip out of your hand."

Stephen: Thanks tons for the images. He files round. I'm thinkin you guys are right about the rakers. A heavy right-hand stroke wld be enough to do it.

Peter: Thanks for the comprehensive response. Hadn't thought of all of those possibilities. Will check em all.

Steve: Yeah, that's the interesting part. His saw just flies through the first fourteen inches of the cut, but then totally locks up. Man, I wish you guys cld feel it. You'd probably know what it was at once.

Dave: Me too. I always take my gullets all the way out with square grind--way better chip flow. Oh and by the way Stephen, thanks again for the Madsen's stuff, but--to me--those guys can be a little confusing. For instance: their label over the image of the "end of life 'wrong,'" chain. E.g. the only reason it is "wrong" is because your chip flow will really slow down, which causes the cutting to slow down. But, if your angles are straight, your saw will cut straight; other things being equal.
 
If it was the bar rails being out of square, seems like it wouldn't be cutting straight to begin with, it would be angling off. Same with left and right cutters out of balance.
 
It has all been said.......but even when you know how to file, how to set depth gauges , how to dress a bar etc, ocassionally you get a bumfuzzler. It has happened to me a couple of times where everything looked good but wouldn't cut straight. In those cases it probably stemmed from forcing a dull chain trying to finish dirty stump cuts. Once you achieve uneven wear on the tie straps no amount of "perfect" filing makes things track straight. I also once got a bar that was softer on one rail than the other! Dress it put on a new chain and soon it was lopsided again. Not sure how that happened in the heat treatment but throwing that one away made life easier.
 
I've posted this many times, but I'll do it again for those who haven't seen it. Having a right proper filing station makes all the difference to me.
 

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Whatever it is I'd be razzing the hell out of him and telling him as foreman he better get it 'squared' away.
 
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