crooked cut

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Hi all,
Lurker here, who just joined.. Got a chain problem, searched through old threads, and still cannot solve the problem.
Chain cuts good up to 3-4" into log, then wants to go crooked or bind. If i turn the log and cut from the other side, same thing.
Tried a brand new bar, problem still occurs.
Sharpened the chain so all teeth are near the same, problem is still happening... All the other chains I sharpen have no issues.
The chain has about half life remaining.
Its not that I need it, but now that I have been working on it, trying to get it to cut correctly, its become my mission to solve the issue. What should I look at next?
I sharpen on a bench grinder, if that matters.
Thanks for the help, Greg
 
Yes I did.. I will say, I am not a professional grade sharpener, but have done it for sometime, and never had a problem before like this.........
Is it possible a chain can just be "bad"?
 
I've never had a really bad one. Lots of factory issues that can easily be resolved by a proper sharpening sometimes tho.

but I think the answer is possibly?

there's a master or two around here that will chime in at some point...
 
Thanks. I learned more from reading some of these guys posts then I ever thought possible..
 
It's possible that they made a run of chain with all the cutters leaned over on one side or something, but I've never seen that.

My guess is that you're using the kind of raker gauge that lays on top of a tooth and subtracts 0.025.

Here's a more complete view of why they say you should set all the teeth and rakers the same to cut straight. The devil is in the details.... and it turns out that you can cut crooked with all the rakers the same height, and you can cut straight with different length teeth.

What makes a chain cut crooked? One side grabs more than the other.

W
hat makes a tooth grab? Top plate angle, hook angle, and the angle that the wood hits the cutter at (which is determined by the raker and the saw operator).

Could be the bar, but you ruled that out. So the chain!

Almost nobody hand-files both sides at the same angle or to the same size. My neighbor says he is an expert lifetime hand filer, and his actual angles and tooth sizes are terrible. I know this because his chains come to me for fixing. This isn't criticism of him- this is typical of a used chain once you look at things with a micrometer and an angle gauge.

Anybody who says they are a great hand filer and also says sometimes you just need to take a chain in to be sharpened- they are struggling to admit the truth to themselves. Almost everybody is laughably bad at eyeballing this stuff. It took me 30 years to admit that I was terrible at hand filing- but once you bite the bullet and start measuring your results with a micrometer, you are forced to admit certain truths. :laugh:

Teeth lean, chains lean on the bar, and the same size tooth looks a lot different from the front and the back sides. People are bad at telling whether left side cutters and right side cutters are the same size and whether rakers are the same height via eyeball.

They're also bad at telling whether the top plate angle is the same on both sides, especially if the chain has no witness marks. This can make you go crooked all by itself, even if all your sizes and heights are perfect. (Although @Philbert has a great photo in another thread... if you twist the chain a little and hold a left side cutter exactly side to side with a right side cutter, the Mark I eyeball gets a lot better at telling what's going on.)

Rakers have the same issue we just discussed, and are critical to determining how much grab its tooth has. But rakers are even trickier than cutters if you are working via eyeball, because it's the angle between the raker and its cutter and the wood that matters- not the height of the raker.

So your typical hand filer will normally have this side teeth shorter than that side teeth. Then they take a raker gauge that sits on the tooth and subtracts 0.025" (now we're cutting crooked because the short tooth is catching air while the tall tooth is grabby and overstuffed with wood). Or they use a raker gauge that lays across two opposite side teeth and subtracts 0.025" (this is better but still crooked). Or they use their magical eyeball and pick a height that looks right (anything could happen with this one).

Take a crooked cutting chain with perfect top plate angles but different size teeth on either side. Perfectly set all the rakers to 0.025" below the height of each tooth. It will still cut crooked, because the long tooth grabs more than the short tooth.

Now take that same chain and set all the rakers to about a 6° AoA for each tooth. It'll look funny, but it'll cut straight again (remember, the top plate angles are the same on both sides for this chain), because each tooth is taking the same size bite of wood as it comes around.

So the conventional wisdom for this situation would be to go get a pair of calipers and a file guide, find the shortest tooth, file all teeth back to that length and fix the top plate angles while you are at it, and then set all rakers to .025" below tooth height. (And that will make it cut straight.)

Alternatively, you can just fix top plate angles and adjust raker AoA and get a funny looking but straight cutting chain.
 
I'd say just buy a new chain. And a new sprocket probably wouldn't hurt either.
You could try filling the rakers down on the teeth on the other side of the crook, to try to get it to cut straight.

The most important thing though to prevent this in the future is to take the same amount off every tooth. And the same amount of strokes of every raker, so that every tooth on your chain takes the same size chip
 
Jetsam, Thanks for that detailed write up... Sure is way more to it,then just taking a file and hitting the edges a few times.. LOL...
My hand filing days are done!! Next snow storm, I'll get out the calipers and start measuring.. Thanks!
Big Hank- "I'd say just buy a new chain." I'm starting to like that advise!! Sprocket is not worn at all. So I can rule that out too.. maybe...
 
Jetsam, Thanks for that detailed write up... Sure is way more to it,then just taking a file and hitting the edges a few times.. LOL...
My hand filing days are done!! Next snow storm, I'll get out the calipers and start measuring.. Thanks!
Big Hank- "I'd say just buy a new chain." I'm starting to like that advise!! Sprocket is not worn at all. So I can rule that out too.. maybe...
Get a new chain.
 
Get the calipers and the new chain, and start reading about sharpening (there is a lot of great stuff right here). You'll end up needing a way to set top plate angles (filing guide, jig, or grinder) and a way to measure lengths and heights (dial calipers). There is a LOT of discussion about all of the above here and on other forums.

By the time the new chain is too bad to use, you'll be ready to sharpen both of them correctly.


The 'right' approach depends what you want out of chain sharpening.

A guy who owns a tree service wants a sharp chain without spending a valuable hour screwing with it, so he'll send it to a grinder or buy a new one. If he values his repair guy time at $20 an hour, even that guy isn't going to be looking at loops with dial calipers- set the grinder angles and go.

A guy who enjoys maintaining his own tools should learn more about it. It's interesting and rewarding, and your saw will always be a light saber.
 
Get the calipers and the new chain, and start reading about sharpening (there is a lot of great stuff right here). You'll end up needing a way to set top plate angles (filing guide, jig, or grinder) and a way to measure lengths and heights (dial calipers). There is a LOT of discussion about all of the above here and on other forums.

By the time the new chain is too bad to use, you'll be ready to sharpen both of them correctly.


The 'right' approach depends what you want out of chain sharpening.

A guy who owns a tree service wants a sharp chain without spending a valuable hour screwing with it, so he'll send it to a grinder or buy a new one. If he values his repair guy time at $20 an hour, even that guy isn't going to be looking at loops with dial calipers- set the grinder angles and go.

A guy who enjoys maintaining his own tools should learn more about it. It's interesting and rewarding, and your saw will always be a light saber.
The chain and bar are the most overlooked part of a saw by the inexperienced chainsaw users, In my humble opinion. Hand filling is muscle memory, takes a lot of practice and you have to know what to look for.
 
..and as far as knowing what to look for goes, having a new loop with a factory grind on it is a pretty decent reference.
 
Cutting crooked to the point anything beyond 4 inches in diameter goes into a bind but looks like the chain is OK. Other chains not such issue. That is bordering on hard to believe. Maybe not exactly what post 1 states. Perhaps the side of the cutters on one side got rocked or has not been ground back enough. Try with a fingernail, the top of the fingernail and see if the sharpness digs in on top, corner, and side of both sides. That is pretty fast to bind up and look OK.


One could also take a chainsaw file of the proper size or a little less and hold it in position and assess the angle from the bar and what % of the file is above the top of the tooth. The request was what to look at next.
 
Does the chain guage match the guage of bars you have been using? As previously mentioned I'd suggest inspecting & comparing your chain to a new one (including drive links/ tie straps etc not just cutters/ rakers). Some well focused close up pics of your chain will probably help us give more specific advice
 
Would also like to see what the existing chain looks like with a picture.

Most common is the right side teeth has been rocked and the working point is flat bent down. Then the good side of the chain has a good working point and cuts into the wood and pulls the kerf that direction. A picture will tell a lot of words and how to best advise you fix it.

Even if you don't post a picture look at the leading point on the top plate, if it was been munched then you need to bring that point back. A few swipes with file or lightly stone ground wont cut it.
 
How much is your time worth? How much is a new chain? For me, that answer is simple: buy a new chain. I don't have the time, patience or desire to break out a set of dial calipers and gauges, stop production for however long it takes to sharpen it, etc..... Im putting on a new chain.
 

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