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What makes a chain grab?

stehansen

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I am in the middle of a large job removing 23 pine trees that are pretty tall and slender and so I bought a 32" bar and a couple of chains for my 660 as the 42" bar is pretty cumbersome. It has full skip chain on it and this may be the problem but the chain is really grabby. It sometimes will stall the chain and you have a hard time getting the chain out of the cut it is so deep in the wood. The chain is brand new Stihl chain. The guy at the saw shop talked me into full skip and I'm thinking I should have went for semi skip, or it may just be a bad chain. OH, both chains do this.
 
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Frans

Guest
Rakers are set at the factory to allow for the 'best' cutting in a wide variety of wood types.

Pine is soft, so the chain grabbed(s) more. Try it on hard wood and see what happens.

I run my chains straight from the box, but when I sharpen them I think about what job I will be using it on.

Usually my schedule changes and this backfires, but sometimes I get it right and then the joy starts!
 

sotc

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rakers or maybe your getting sawdust built up in the cut and its getting under your chain?
 

Old Monkey

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For good cutting, keeping your RPMs up is important. Before I dog in I cut down on the power head side and then I lift up an inch before I dog in and cut down. The teeth closest to the power head are the ones that stall out the chain when they take too much so when I am dogged in I make certain they are not all engaged. Does that make sense? I could show you in half a minute but describing it is hard.
 
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xtremetrees

Guest
Husky helps prevent the dogging in! Due mostly in part to thier incrediablely high rpm derived mostly from combustion based on ingenious engineering from the brains most likely similar to Einstein!

All kidding aside, I've only run a full comp skip tooth (got one on my 440 now) a few times. Could be not enough teeth to clean out the saw dust and the dust is going into the bar itself.? err what sotc said.
 
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fishhuntcutwood

Guest
Do you mean grab as in jumpy and rough cutting, or grab as in bog down in a cut? You mention sometimes bogging, so....

For good cutting, keeping your RPMs up is important.
Bingo. All else being equal, saws need rpm to cut. Lose rpms and the chain won't work. It could be the depth gauges are lower than what you're used to if you do your own chain, and this chain is brand new. They're probably at .030 if they're factory (if memory serves). But if you do your's at .020 when you sharpen, the chain will feel more grabby, and can bog.

Beyond that, skip chain is meant to keep rpms up and help with chip clearance. Fewer cutters put less load on the chain and saw, and rpms (all else being equal) will stay up. Likewise, fewer teeth in the cut allow more room for chips to "ride" the chain out of the cut, and thus, less clogging. (Again, all else being equal.) But full comp chains can feel smoother, and less jumpy. I run full skip 95% of the time, so I don't even hardly notice it being any rougher or less comfortable.

All that being said, a healthy 660 should manage a 32" through pine all day long; and even with full comp if need be. I'll run mine with a 36" in fir all day long and the saw never slows down.
 

gf beranek

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Number one I'd say rakers.

Factory sharpened chain off the roll is not always uniform. I use to buy it by the 100 ft. rolls and perodically a section would be ground differently than the rest. I suspect the machines that do the grinding at the factory have to be periodically dialed in and so every once in a while that is why I would find 15 to 20 feet in the roll ground too long, short or otherwise not like the rest. It showed up as a grabby chain once. Left me wondering til I looked close and seen why.

That may not be the case with you. But still check the rakers. In pine you should get by with .035 just fine with the 660.
 

Burnham

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Husky helps prevent the dogging in! Due mostly in part to thier incrediablely high rpm derived mostly from combustion based on ingenious engineering from the brains most likely similar to Einstein!

All kidding aside, I've only run a full comp skip tooth (got one on my 440 now) a few times. Could be not enough teeth to clean out the saw dust and the dust is going into the bar itself.? err what sotc said.
Make up your mind, Robert...it is either full comp or full skip, but it surely is not both.
 

squisher

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Maybe 'reaming' out your cuts every now and then as well to help clean out the sawdust, like backing off with the saw still revving and sliding the bar back and forth and in and out of the cut.
 

Al Smith

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This might not be the case but on a long bar in a deep cut if it is cutting the least bit crooked it will eventually bind.

You won't see it too much if you are bucking straight through.However if you say go part way through then swing over the top it will show up .This can be a bit annoying at times.
 
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Frans

Guest
This might not be the case but on a long bar in a deep cut if it is cutting the least bit crooked it will eventually bind.

You won't see it too much if you are bucking straight through.However if you say go part way through then swing over the top it will show up .This can be a bit annoying at times.
if the chain and bar are straight, then if that happens it is from someone who doesnt know how to use a big saw properly
 

stehansen

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  • Thread Starter Thread Starter
  • #18
Boy, I knew we couldn't be serious for too long. So, assuming the rakers are a little aggressive should a few sharpenings straighten me out? Chain is tight, bar is brand new, cutting straight as an arrow. I sharpened the chain by hand last night but we didn't use it today. I was planning on this thing cutting like no one's business.:(
 

squisher

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And yes if your rakers are to agressive a few good sharpenings should go a long way to straightening it out.
 

Magnus

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As I see it eash tooth has to carry the dust it cuts out of the wood.
A aggressive chain will fill the tooth fast and ride along further without working than a tooth with a higher raker.

When it transports the dust it is possble it tries to get behind the tooth by forcing it to the side, it it has a bit of travel in wood...

If you paint the cutters with a marker pen you can see what happends.
This is very educating to do.

Another thing to do is cut a thin end , just a couple mm thick, stop in 2/3 of a cut, breake the disk of and have a look what is going on.

These two combined explain a lot.

A good thing to know is that if the rakers are set too low the tooth will want to go sideway's a bit. The tiestraps will be heavely loaded and bar/chain wear much faster. The saw will get a workout, but the chain will get a beating.
 
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