Slight OT - Flattening Chainsaw bar...?

Howdy,

I pinched, and then had to replace the bar on my Husqvarna chainsaw.

As I removed the cardboard "scabbard" in which it was packed I saw printed information about maintaining the bar.

One step involved using a flat file held flat on the side of the bar to remove the burr that forms at the edges.

My question is this:

Why would that be necessary? Or, said another way, what problem might one have if the burr were simply left where it formed?

Thanks for any help on this,

Reply to
Kenneth
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Three reasons.

  1. It is there due to the wear of the chain against the bar. As the chain wears into the bar, the surface to surface area is increased causing more friction and thus more heat and wear.

  1. The burr on the sides of the bar increase the width of the bar and make it harder for the bar to go into the groove made in the wood you are cutting. The bar becomes wider than the groove it needs to go into.

  2. The burr is rather sharp and adds to the danger of cutting oneself on the burr.
Reply to
Robert Allison

If you heat up the bar by either running with too little oil delivery to the bar, or trying to force a dull or poor cutting chain through a hunk of wood, etc. you will develop this burr, or edge along the bottom of the bar. It is something you will be able to feel, but it's really quite small. Small is enough though. It's all you'll need for the bar to hang up in the cut. The cutters on the chain don't cut much wider than the width of the bar itself and when you build up the burr the bar will hang up in the cut. So... the problem you will have if you tried to leave the edge there is that you'd not be cutting too much anymore.

Reply to
Mike Marlow

Reply to
Wilson

And yet nobody gave the primary reason why the edges of the bar peen over, which is a slack chain and sideloading.

Take a rock with one side's teeth and see how fast that sucker wears.

Reply to
George

the deal is after time a wire edge or burr comes on to the bar from friction of the bottom of the chain on the rail of the bar. this can be minimized by keeping the chain sharp so it pulls thru the wood without excessive down pressure on the bar, however after time it happens and left on the bar will tend to hange up while cutting causing it to want to cut crooked. sometimes it takes putting the bar on a bench grinder or disk grinder to flatten the rail's to 90 degrees of the bar itself, this is when one side is worn more than the other also causing the saw to bind in the cut. ross

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Reply to
Ross Hebeisen

I'll answer with another question. How many cords a year do you cut and does your saw provide adequate oiling?

Answer: If you have adequate oiling, turn the bar over every 3 cords or so, and only cut 1-2 cords a year, the problem will never occur. If you have inadequate oiling, don't ever turn the bar over, or cut a total of 15-20 cords you will probably need to file the bar. First, you top file the bar to flatten the surface that the chain rides on (makes the chain ride flat on the bar)and then you file off the burr on the side to make it smooth. With the bar in a good good vise, filing an 18" bar will take about 8 minutes. It just makes the cutting smoother. Or, you can just throw away a good bar and go buy a new one for $20 or so.

Reply to
George E. Cawthon

I should really hope not. What you are talking about (I think) is the chain wearing more on the cutters on one side than the other. That's an entirely different issue. This is usually more of an operator error than it is a use problem.

Reply to
Mike Marlow

Correct-a-mundo. You just had to go and point that out now, didn't ya George. Ok - you get the prize. Oh yeah - the prize is the chance to sharpen these old chains of mine...

Reply to
Mike Marlow

So how tight is tight enough? It does not seem to stay tight and my oiler seems to keep things lubed. Relatively low hours bar but it does need a new chain which is in the toolbox. I have a crummy Poulan/Craftsman 16" that does what I need as my property is practically barren except for the scattered cedars I need to remove and a few big pines, sweetgums and oaks in two corners of the property. I also do not have a fireplace. That run on sentance was just to clarify that I do not need a quality chainsaw for the little sawing I do in a year. It has been 20 years since I used a quality chainsaw. I do not recall if it did a better job keeping tight but I think it did.

Reply to
Jim Behning

I must have two/three (ok, six) chains that are "sorta" good hanging out in the garage that I'll put on someday. Sort of like those scraps of wood that breed in the corners of the shop. What I should do is pitch 'em, because one spare is enough. I flip, join and deburr the bar when I start the year's wood in April, but I only do about 10 full cords a year. That's 25 20" face cords.

Granville File-n-Joint is the berries for chain maintenance.

Reply to
George

Tight should be about 1/2 of the chain link that rides in the bar groove. You should be able to gently pull 1/2 or just a bit more of this down from the bar when the bar is cold. Make sure that when you put a chain on, or adjust your bar that you hold up on the nose of the bar while you tighten the bar down. You should end up with a chain that can freely be moved all the way around the bar by hand without a lot of force. Hard to describe what a lot of force is, but you should not have to work at moving the chain around the bar. New chains will stretch and require adjusting the bar during the first use. Are you using a new chain?

As far as the oiler goes, you should be able to hold the saw 6" to a foot away from an object (daughter's boyfriend's head is usually good), and see a light spray of oil coming off the nose of the bar at full speed. If not, turn up the oiler some. Lack of oil is the number one killer of bars and chains. When you've used the saw for a while - long enough to heat up the chain and bar, does the chain coast to a stop when you let off the throttle, or does it kind of scrape to an immediate stop? It should coast. If it scrapes to a stop then the chain is not getting enough oil.

Other than power issues that can be common to lower end saws, you should get reasonable service out of that Poulan/Craftsman. As you say, you don't cut a lot and you don't really work the saw when you do cut. Can't see any reason why that saw would not do what you want - again, assuming it simply has power enough.

Reply to
Mike Marlow

I do the same thing - the chain thing. I end up keeping old chains in case I need a stumping chain, and end up with too many of them hanging on a nail. In the end, I never end up using them. It's stupid to do it too, because new chains aren't that expensive and they sure do cut better.

I used to have one of those. Don't know what ever happened to it. Now I just use a file guide.

Reply to
Mike Marlow

The key is to put a block under the tip and push down on the saw when you tighten the chain and the bolts holding in place. Otherwise the bar will move some when it gets hot. You should be able to put the chain about 1/8 inch away from full contact when everything is cold. When it is hot it might sag 1/4 inch.

Reply to
George E. Cawthon

Stuff about chain saws. As a young man, I used little 12" bar and big chain saws up in the trees and on the ground. I've used the old two-man saws, alone and with another person, and many brands of saw. After hundreds and hundreds of trees, oak, pine, wild cherry, poplar, and clearing land, I have learned a lot about chain saws. As far as cutting to the right or left, some cheaper chainsaws aren't center balanced but are motor weighted to the left, and will drive you nuts anyway. If your saw is balanced, the follow info applies. I've mostly changed my own bars and chains, and sharpened my own chains by hand, except when a saw was in for engine repairs. The secret of maintaining a good chain is to have the proper tension and oil, oil, oil. We used to buy the cheapest motor oil by the gallon and even when a saw had an automatic oiler, constantly pumped the manual oiler. Before you cut a log, you should be able to see some oil being flung off the chain onto the wood. the chains are metal on metal and oil is the only cooling agent. If you are cutting a 24" or larger log, you should stop occasionally and pour some oil into the cut while the saw is still in it. Then continue. If you are cutting a stump, some are pretty large and you will be at it for a while. No matter what, don't touch dirt with the chain blades. Clean around the stump and cut it high to save your saw. We usually kept an older saw with a well used chain for stumps, because touching dirt with the blades instantly dulls them and the heat will start building up on the bar. Sharpening: If you have the right size rat tail file for the blades, you can touch the blades up evenly, any time you want. Keep them sharp. You don't need a machine sharpener. Ever. The machine sharpeners tend to sharpen conservatively, straighter across than I like. An angle is nicer. Sharpen from the concave cut, across and finishing with an upstroke up. You don't want to cause a deep concave groove in the blade or it will "dig" to much and slight differences on right or left blades will exaggerate any left or right pull. Sharpen the cutting blades on one side first, then the other. Then if you experience left of right cutting direction, you simply touch up the side that isn't as sharp. It will straighten out. Don't push a chain saw through a log. You can rock it, but let the saw do the work. If properly sharpened it will simply "dig" itself through the log. The cutting depth guides that are part of the little cutting teeth and are in front of each one determine the depth of cut. These are filed down with a flat file when necessary. It is not necessary very often. Here's why. Cutting different types of wood will make the chain saw work differently. If you are cutting something soft like pine, willow, palm, poplar, etc, a sharp saw will go through like butter, and if the guides are filed down, it will throw large chips. If you then cut hardwoods, the chain will bite too much and the saw will work too hard, the bar will heat up, and bind a little. If you are bucking (cutting up from underneath the wood), the saw will throw itself back at you. Use the flat edge of the flat file across the top of the teeth to see how far down the guides are when new, and keep them at that depth, If you break a tooth off, get rid of the chain. Sometimes you will find pieces of metal buried and grown into trees from decades ago, and will damage a chain. It is important to get rid of the damaged chain. A chain with a missing tooth will still cut softwood, but, if you buck from under a hardwood, the chain skipping the missing tooth will catch the next tooth and slam the saw upward into your hand or face. It gets messier from there. Brush cutting is even more dangerous with a missing tooth. When you check the tension of the chain, it should sit comfortably, unexpanded with all the chain guides seated in the bar. It shouldn't hang to where the guides along the bottom of the bar are not seated, but you may see a portion of a few guides. The chain will loosen after the first use, so tighten it a little when it does. You should be able to pluck the top part of the chain upward, and see the guides trying to leave the bar grove, without doing so entirely. If you aren't stretching the chain pulling upward, but there is the same amount of play you would leave in a wheel bearing, you've got it. Remember, you can never use too much oil on a chain, and occasionally shut the saw off and clean the sawdust away from the oiler port at the back of the blade.

Reply to
john

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