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Problem with chain locking

Started by Oregon40Acres, January 27, 2019, 07:57:31 PM

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Oregon40Acres

I'm a complete amateur with 20 years experience using chain saws. I suppose that the proudest boast I can make is that during that time, the worst injury I suffered required nothing more than a band-aid. A rather large band-aid, to be sure, but no stitches.

Anyway, last September I replaced my 18" Husqvarna with a brand new 18" Husqvarna. I used the new saw enough to add gasoline twice, then set it aside for the winter. Today was a sunny, somewhat warm day, so I trekked into the woods to thin a few thickets. But I caught a vine as I was cutting, and it threw the chain. Back at the shop, I put it back in place, but it wouldn't rotate around the bar. I tried a bunch of things to figure it out, but the first decisive observation came when I put an old chain awaiting sharpening onto the new saw. It rotated around the bar just fine. OK, that means that the problem is with the original chain. So I took it out into the sunlight and examined it closely. It was well-oiled, no rust spots, and no sticky links. I looked at the inside teeth very closely. There was some wear visible, mostly in the sharpness of the tiny teeth at the tip of each of the inside teeth. Some were quite sharp, but some had been worn down a bit. There was no wear whatsoever on the sides of those teeth, and no bungs or other irregularities sticking out sideways. In other words, those teeth looked fine to me.

So what am I missing? I'm sure that the problem is with the chain, but what could it be? 

lxskllr

My guess is some drive links got boogered up when you threw the chain. Check for burrs, and if you have to force any link into the bar groove, you should check it closely, and file down any high spots.

doc henderson

20 years does not sound like a  novice.  Check the part of the chain that goes into the grove of the bar, to make sure nothing is scored or deformed.  If not, try the chain again, you may have had some organic stuff wedged in there that is now out.  They make a tool in the shape of a hook to clean the bar groove.  I had a chain once get scored and I had to file the drive portion of the link.
Timber king 2000, 277c track loader, PJ 32 foot gooseneck, 1976 F700 state dump truck, JD 850 tractor.  2007 Chevy 3500HD dually, home built log splitter 18 horse 28 gpm with 5 inch cylinder and 32 inch split range with conveyor powered by a 12 volt tarp motor

Oregon40Acres

Thanks, guys. I had searched the forum for similar problems, but found nothing. However, after posting my request, the forum AI found some good discussions, which I read. The most likely explanation seems to be that the chain was damaged when it was thrown. I laid it flat on the table as per one suggestion elsewhere, but it shows no sideways bending. I went through and examined it closely and STILL couldn't find anything wrong. I'll make one more examination under a magnifying glass, but I'm pretty sure that I'll just have to chuck the chain and use a new one. Or maybe sharpen one of the old ones that might still have some length left on its teeth... 

Thanks again!

OntarioAl

Remount the chain on the bar, back off the slack adjuster so the chain hangs loosely.
With a glove on slowly pull the chain along the top of the bar watching where it binds.
a little filing on the drive links identified as tight then retest.
Cheers
Al
Al Raman

Old Greenhorn

Quote from: Oregon40Acres on January 27, 2019, 08:34:48 PM
I'll make one more examination under a magnifying glass, but I'm pretty sure that I'll just have to chuck the chain and use a new one.
All of the the other posters are pointing you in the right direction and your last assumption is likely right. You've been doing this a long time but probably never really gotten into the details of how a chain is made or works, most folks don't. If there is a drive link with a .010" tweak in it you are done with that chain unless you can find it and file out the bend as others have posted. From your perspective, I am thinking you might best write it off and move on unless you want to spend some time trying to understand how chains function. For myself, I could see me killing a whole day trying to figure it out and fix it, but most folks won't do that, and I am not suggesting they should. i bet a new chain, or an old one resharpened with the same pitch and gauge will set your world aright.
Tom Lindtveit, Woodsman Forest Products
Oscar 328 Band Mill, Husky 350, 450, 562, & 372 (Clone), Mule 3010, and too many hand tools. :) Retired and trying to make a living to stay that way. NYLT Certified.
OK, maybe I'm the woodcutter now.
I work with wood, There is a rumor I might be a woodworker.

thecfarm

Oregon40Acres,welcome to the forum.
I have thrown chains and the part that goes into the chain groove will have a burr on it. Yes,the problem is with the chain if another went around fine. Put the chain back on,don't tighten it up.Rotate the chain on the bar.Where ever the problem is,the chain will not be in the grove of the chain. It will be up in the air and you will be able to see between the bar and chain. Mark that spot,remove the chain and file that place down and put the chain back on. Might be more than one place too. Of all the chains I have ever thrown,I never had to throw one away.  
OntarioAl is right with the glove too.
I would hate for you to toss a good chain. Part of learning.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

hedgerow

Welcome Oregon 40 Acres 
It sure sounds like one of the drive links got burred. Seems like with a new chain you really have to watch the tension as they like to stretch when you first start using a new chain. You should be able to take it off the saw and look at the drive links were they would engage the sprocket and find the one or one's that are burred up. I usually use a die grinder with a stone to clean the burrs off. Like others have said a 18 inch chain isn't a ton of money and some times it's not worth the effort and tossing it just makes since. 

Al_Smith

If the driver is bent lots of times you can just crank down on it in a big vise .Then if it's burred use a file or a little stone that goes in a mini die grinder ,Dremel or such .Good as new,cut wood 

Old Greenhorn

Tom Lindtveit, Woodsman Forest Products
Oscar 328 Band Mill, Husky 350, 450, 562, & 372 (Clone), Mule 3010, and too many hand tools. :) Retired and trying to make a living to stay that way. NYLT Certified.
OK, maybe I'm the woodcutter now.
I work with wood, There is a rumor I might be a woodworker.

Old Greenhorn

By the way, if you check the knowledge base here on the forum under chainsaws you will find a link to a great booklet Carlton produced that tells you EVERYTHING about chains, bars, and sprockets you ever need to know. The link is broken and I have put in a request with the update, but here is the correct link. I printed this out in letter size to have for reference when teaching others. 
Go here: http://carltonproducts.com/pdfs/CarltonSafetyMaintManual_EN.pdf
Very nicely booklet and I think Carlton is, or was a sponsor here? The only thing I don't see in there is any mention of square grinding, but I haven't read the whole thing yet.
Tom Lindtveit, Woodsman Forest Products
Oscar 328 Band Mill, Husky 350, 450, 562, & 372 (Clone), Mule 3010, and too many hand tools. :) Retired and trying to make a living to stay that way. NYLT Certified.
OK, maybe I'm the woodcutter now.
I work with wood, There is a rumor I might be a woodworker.

Oregon40Acres

Quote from: Old Greenhorn on January 27, 2019, 10:12:00 PMFor myself, I could see me killing a whole day trying to figure it out and fix it,


I'd like to know what went wrong, too, but after putting about four hours into various tests and examinations, I've decided that I need to get back to cutting. I just got back in from cutting down 13 small Douglas firs, all dead or dying from hot dry conditions from the last few years. I've got eight big Douglas first close to the power lines; I don't dare touch them. I have to call the power company to get them to take down those trees. There's another big old Douglas fir right at the corner of my house that's dying, and even though it's leaning way over away from the house, I'm still going to hire a professional to take it down safely. There are some things I know I have to leave to the pros. Ever watch those YouTube videos of idiots with chainsaws? I'm not that dumb, but I don't ever want to star in one of those videos. Those videos are great educational resources; they truly make you respect how tricky it can be to bring down a tree.

One other thing: the outside air temperature right now is 51ºF. I expect that some of you guys further east of me would really appreciate such balmy temperatures about now.

doc henderson

thx Oregon for the f/u.  glad you are back cutting wood.
Timber king 2000, 277c track loader, PJ 32 foot gooseneck, 1976 F700 state dump truck, JD 850 tractor.  2007 Chevy 3500HD dually, home built log splitter 18 horse 28 gpm with 5 inch cylinder and 32 inch split range with conveyor powered by a 12 volt tarp motor

Old Greenhorn

@Oregon40Acres check out that booklet I posted the link for and go through that chain on a Sunday afternoon when you have time to kill, not wood to cut. You will figure it out and we'd all like to know what you find. Or you could send it to me and I'll figure it out ad send it back, unless it trashed. There is a solution to every problem, it just takes a steady mind and a steady hand. You'll get it yet.
Tom Lindtveit, Woodsman Forest Products
Oscar 328 Band Mill, Husky 350, 450, 562, & 372 (Clone), Mule 3010, and too many hand tools. :) Retired and trying to make a living to stay that way. NYLT Certified.
OK, maybe I'm the woodcutter now.
I work with wood, There is a rumor I might be a woodworker.

Oregon40Acres

OK, thanks. I downloaded it and will read it soon.

Oregon40Acres

You folks will be pleased to learn that you were right about the chain inner teeth being bunged. I had inspected them with a magnifying lens and found nothing, but then I carefully cleaned the whole chain and examined it under a magnifying light. Sure enough, I found eight inner teeth that were damaged. The damage was hard to see, I could barely feel it with my fingertips. But I carefully ground them down with my Dremel tool and now the chain works just fine. 

Thanks again for all the help!

sawguy21

And so concludes your first session of Chain 101. ;D
old age and treachery will always overcome youth and enthusiasm

Al_Smith

A thought FWIW .If a person isn't paying attention the drive systems can be worn out to the point of damaging a chain .The slots in a rim drive or the cogs in a spur sprocket wears to the point of contact on the drivers of the chain causing  the chain to rise up contacting with less area of the driver .Worst case is a rim splitting .That will really hammer the drivers .
Due to my own fault I split the rim running a 32" bar which turned that chain into "cut down" to  a 20" loop .A rim is relatively inexpensive .From 5 to 8 bucks depending on who made it .

mredden

Saturday, I threw a brand new 36" chain on a brand new bar. When I say "threw a chain" I mean it threw with enough force to knock the bolts off the sprocket cover! Bolts were okay, but threads in nuts were damaged.

I am not sure, but I think a driver may have been defective. I had trouble getting the chain tension set right. Since it was a brand new (ripping) chain, I wanted it slightly tighter than normal because I expected stretch. Every time I thought I had it right, I would tighten down the bolts. Once tightened, the chain would not spin by hand. After an hour of frustration, I took it out of the mill and set it looser than I like. It spun by hand, but maybe not as freely as it should. I then planned to noodle three chunks of live oak (ugh). First one cut beautifully. Second one cut good and I checked the chain "hang." Not too bad. Touched the third piece, and it blew up.

I took the saw inside and checked the bar. It appeared perfect. Put the chain on. Tightened it a bit and spun it then tightened a bit more. Then I pulled up on the chain in various paces until I felt resistance. Marked that spot on the chain with chalk and removed the chain.

Put the chain under a magnifier and there it was. One driver was ugly -  not chipped but the metal just didn't look smooth on the sides of the driver. The next driver had a slightly chipped tooth. Next driver looked fine. Fourth driver did not look chipped but the tooth was not sharp. Tried to flat file them but the drivers still did not run smooth in the bar and there was still some grab when I did a pull test.

Dremel time. Just ground the sides of the "ugly" driver smooth and smoothed out the tips of two teeth. Put on two new nuts and tightened chain to usual tension. Spun by hand. Viola! No more chain problems. Smooth as can be and I cut four oak slabs Sunday afternoon just to check.

I believe the "ugly" driver was defective from the start. It caused the chain to hang up  in the bar just after passing the sprockets on either end. The two teeth were damaged by the throw. I could be wrong.

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