chainsaw chain


I have a chainsaw where the chain wants to not stay in the bottom of
the blade. There were some notches (2 sets) in the drive gear/sprocket
(clutch hub) so I replaced that. I figured once it moves over to the
outboard notch, the chain wouldn't stay in the blade.
Once a motorcycle chain stretches, it will wear out the sprockets
faster. The chainsaw chain stretches like crazy compared to a
motorcycle. The chain is driven differently on the chainsaw though.
So like on a motorcycle should the chain be replace when the sprocket
is
replaced?
The saw worked fine with the chain out of the blade. I do have a groove
in the plastic cover that holds down the blade.
Thanks,
Wayne D.
Reply to
Wayne
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Are you calling the bar the blade? The bar is the grooved flat carrier of the chain that has the slot all around to hold the chain in place. I would think that the sprocket would be made of hardened steel, and last through several chains. If you get excessive sprocket wear, something's not right. Check to make sure your oiler is working and not plugged up. A lot of people use their chainsaw and never blow it out with air, or disassemble slightly to clean out the shavings, and they can become hard packed or freeze, and all bets are off. Disassemble frequently, and blow it out, or at least brush it out, and make sure the oiling channel is free flowing. When I use mine, I have a scrench (T handled screwdriver with two sized hex sockets), and I adjust the tension frequently as needed. Watch for any heating up and burning or scorch marks on the bar, as that indicates a lack of lubrication by the oiler.
Steve
Reply to
Steve B
Wayne, I'm not sure what the question is. Yes, chainsaws get hot, the chain expands, it requires tightening the blade several times while out working. No, there is no requirement to change a chain until it is dull. As long as it is making sawdust it is fine. Most chainsaw blades are filed so they are "safer" and don't take large bites. This is controlled by the height of the rakers. A chain might be sharp, but not taking very large chips that will require filing the rakers down lower - some pros keep the rakers quite a bit lower to have a more aggressive chain.
When tensioning the chain, hold the blade up and tension until the chain has slack, but the drive links don't come completely out of the blade slot on the bottom of the chain. It is quite normal to have gouges, nicks, and grooves in the drive sprocket. Make sure you are spraying a small bit of oil while cutting - it helps clean, cool, and lube the chain.
Reply to
DanG
On a chain saw, the chain will not wear out before you have sharpened it to the condition it is no longer usable and then replace it. After a dozen or more chains, the bar will have worn on the bottom and on the tip to where it will need to be replaced. I have an old Homelite saw with the engine worn out that has never had a sprocket replaced and has had only one new bar.
All chain saws have a tank for bar oil. This is very thick oil and will slowly leak out onto the chain so it will lubricate the bar channel. Some saws also have a pump for the bar oil so you can manually apply the oil, like when you first start the saw, or are cutting into dirty wood or pitchy wood.
Sounds to me like your saw it not getting any bar oil and/or the chain is not the correct one for the saw. The drive sprocket will get chewed up if the chain is slack and is allowed to jump off the bar and hang up in the drive sprocket. Other than that, anything that would damage a sprocket will get blown out and away by the sawdust.
Paul
Reply to
co_farmer
...
Point the tip of the bar at a clean smooth surface like the end of a freshly cut log and rev up the engine. You should see a stripe of oil build up on the wood in a few seconds.
jsw
Reply to
Jim Wilkins
Originally I had the chain too tight. I thought maybe the groove in the sprocket were caused by that. I'm adjusting it properly now. Oil is properly flowing to the chain.
DanG wrote on 12/25/2009 :
Reply to
Wayne
I keep the chainsaw cleaned up with compressed air after using it. I check to make sure oil is coming out after reassembly. My problem is the chain likes to ride out of the bar on the bottom and then continues back into the bar. If I don't turn the saw over and look, I don't even know anything is wrong.
I took it to the dealer to get it repaired. They said a bad clutch could cause that problem. When I got it back from them they said everything was fine and charged me to adjust the carb.
So I'm now trying to figure this out on my own. I put a picture in the dropbox (csgroove1.jpg) of the groove that is created in what the manufacturer calls the sprocket guard. It is the cover that holds the blade down.
I don't ever let my chain get to loose. It has never been thrown. Some other guy's saw I see the chain hanging down. Another guy doesn't do anything to his until the chain gets thrown.
Wayne D.
Reply to
Wayne
Um, I meant bar... I knew that!
Wayne D.
Reply to
Wayne
Well, as for your original question, yes, it is generally better to change sprocket and chains as a set - whether your set of chains is two or six. Rotate through the chains as they need resharpening, and when the whole set is worn out, replace the chains and the sprocket.
The size of your set depends mostly on how much work you are doing, and somewhat on how much filing .vs. grinding you do for sharpening (filing can be done in place, grinding usually means swapping the chain off for a sharp one, grinding it, and then it's on the "sharp" side of the set).
Even if you are regrinding regularly, you should file with every tank of gas, unless you are cutting some mythical clean, non-abrasive wood that does not cause chains to dull. More often if needed. If not very dull, it need not be much of a filing.
BTW - if there is sawdust the chain is dull. There should be chips. Dust is dust, chips are small chunks of wood the width of the chain, length varies. If you are getting dust, change chains.
Saw chain heats up, especially when dull - this makes it longer - it's not actually stretch, but it may mean you need to tighten once the saw warms up - in which case you should slack off at any long breaks (lunch or the end of the day) since the chain will cool and shrink and get very, very tight if adjusted to run well when hot. If running very hot due to being dull, you should change for a sharp one or sharpen it, rather than fiddling with the tension. Likewise make sure there is enough bar oil being delivered to the chain when running, and fill bar oil every time you fill fuel.
Reply to
Ecnerwal
Well, sounds like you are doing everything right. If you adjust the chain tension when it's cold, it should follow the groove in the bar. both top and bottom. Sounds like the chain is coming out of the bottom groove in the bar when it's hot. This is normal and like you said, it reenters the groove before it gets to the sprocket. The only time this will cause a problem with sawing is if you get the bar in a bind so the chain doesn't return to the groove and hits the sprocket at an angle. This is what throws the chain. But you said the chain has not come off.
Everyone should experience a chain coming off sometime in their life! Wear leather gloves.
Just tighten the chain after every time you sharpen it and should be ok. Look at other peoples chain saws and see what their sprocket looks like.
Paul
Reply to
co_farmer
Loosen the chain until it really sags under the bar enough to feel the bottom of the bar with your finger. DO THIS CAREFULLY, as there may be a razor edge there. It should be square sided around the bottom of the bar, that is at right angles. If there is a T where the too tight chain has deformed the metal, then it may have worn into the groove enough for the chain now to be riding on the bottom of the groove, instead of the sides. You could file off the T if there is one there, but check the depth of the groove, and the depth needed for your chain to run without hitting the bottom of the groove. If it has worn off a lot of metal, replace the bar. With the lack of lubrication, the increased wear from tension, plus the dirt and abrasives passed through there, you can smoke a bar real fast. When I adjust my chain, I like it to hang about 1/8" drooping under the bar, but not so that the teeth come out of the groove. Check after tightening the nuts, because that always seems to make it move one way or the other. Have a scrench in your pocket, and check often. Use the point of the scrench to dig out sawdust from wherever your oil hole comes out, if you can reach it on your model of saw.
Steve
Reply to
Steve B
On some saws, when the bottom of the bar becomes worn, you can flip it over and have another life in the bar. Do that finger check thing I described in the other post.
I thought you meant bar, but never a-ss-ume.
Steve
Reply to
Steve B
"Ecnerwal" wrote
Likewise make sure there is
Got a gallon of bar oil on sale the other day. A little over ten bucks. Ace sells it for six bucks a quart. Sheesh.
Steve
Reply to
Steve B
It is a general bad concept to blow with pressure particles off because you might blow particles into small cracks. Same goes with the lathe and mill.
Martin
Wayne wrote:
Reply to
Martin H. Eastburn
On Sat, 26 Dec 2009 19:30:30 -0800, the infamous "Steve B" scrawled the following:
Steve, it frequently goes on sale for ~$4 at BiMart here in the PNW.
-- REMEMBER: The sooner you fall behind, the more time you'll have to catch up!
Reply to
Larry Jaques
I have trouble digging out the gunk because there are so many tiny places in there especially around the clutch, the kickback brake, and sprocket. It is impossible to get the stuff out, even if you use dental picks to get in there and loosen it. I do see your point, but I really do a thorough cleaning, even having made a support stand on a tire rim for just this. Have had no problem with small cracks yet, as they lead to nowhere. Except for the one tiny channel leading to the oiler, and that cleans out with a small piece of piano wire.
Steve
Reply to
Steve B
Still, ten is better than sixteen.
Steve
Reply to
Steve B
And you can get it at Autozone for 99c a quart. Or run your used engine oil through a Mr Coffee Filter and fill up the tank.
its not like its going to do anything besides cool the chain as its being thrown off.
Gunner
"I am for doing good to the poor, but I differ in opinion of the means. I think the best way of doing good to the poor, is not making them easy in poverty, but leading or driving them out of it. In my youth I travelled much, and I observed in different countries, that the more public provisions were made for the poor the less they provided for themselves, and of course became poorer. And, on the contrary, the less was done for them, the more they did for themselves, and became richer." -- Benjamin Franklin, /The Encouragement of Idleness/, 1766
Reply to
Gunner Asch
On Sat, 26 Dec 2009 22:17:25 -0800, the infamous "Steve B" scrawled the following:
Or $24 at Ace. Egad! "Now with PURE GOLD flakes inside!"?
-- "I believe that sex is one of the most beautiful, natural, wholesome things that money can buy." --Tom Clancy
Reply to
Larry Jaques
Try ether starting spray, or brake cleaner. Both work well.
Reply to
Stormin Mormon

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