Chainsaw cutting to the right

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mtcox1791

Member
Aug 16, 2017
31
Upstate South Carolina
Admitted novice. I have noticed that my chainsaw (MS 250) is cutting to the right with larger rounds, 20 inches or so. I do not notice it with smaller cuts. It still seem to cut quickly with good chips. I notice it when I am about half way through the cut, it stars turning to the right. Trying to guide it straight seems to cause teat to bog down, so I just let it cut to where it wants to go. I have researched this and believe it is because of filing differences from one side to the other. I use a 2-in-1 sharpener, which I love. I don't have a caliper, but stacked feeler gauges and cant see much difference in cutter length. I know a caliper would be better, but don't have one. I know a grinding sharpener would fix this but don't have one.

My question is which cutters should i file more to correct this with cutting to the right. I suspect it is the cutters that face to the left (non dominant hand filing) as they appear when holding the saw?
 
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EbS-P

Minister of Fire
Jan 19, 2019
1,473
SE North Carolina
Check that your bar rails are square. Fast way to check if the rails or chain is flip the bar over.

Evan
 
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thewoodlands

Minister of Fire
Aug 25, 2009
14,009
Foothills of The Adirondacks
Admitted novice. I have noticed that my chainsaw (MS 250) is cutting to the right with larger rounds, 20 inches or so. I do not notice it with smaller cuts. It still seem to cut quickly with good chips. I notice it when I am about half way through the cut, it stars turning to the right. Trying to guide it straight seems to cause teat to bog down, so I just let it cut to where it wants to go. I have researched this and believe it is because of filing differences from one side to the other. I use a 2-in-1 sharpener, which I love. I don't have a caliper, but stacked feeler gauges and cant see much difference in cutter length. I know a caliper would be better, but don't have one. I know a grinding sharpener would fix this but don't have one.

My question is which cutters should i file more to correct this with cutting to the right. I suspect it is the cutters that face to the left (non dominant hand filing) as they appear when holding the saw?
This has some good info, save the link.

 

jetsam

Minister of Fire
Dec 12, 2015
5,283
Long Island, NY
youtu.be
If you are using fixed-depth raker adjustment, your tooth length is probably different on one side (file down the other side to match). Common filing error.

If you are using progressive depth raker adjustment, it's more likely to be a raker issue, as tooth length doesn't matter near as much. Make sure you are checking and filing the rakers the same way on both sides of the chain. Adjust tooth lengths to match the low rakers on the low side.

Also possible that it's the bar, but 9.5 times out of 10 the novice issue is fixed raker depth and uneven tooth filing.

A grinder would absolutely not fix your problem. With a grinder or a file, the first step is to know what a good chain looks like (keep a brand new one onhand if you want a physical reference to look at). Most grinders, especially cheap ones, tend not to cut both sides the same length by default- it's up to the operator to make that happen.

I suggest you get some calipers- you can get some basic ones for $5 or $10, which will let you find the shortest tooth. I suggest spending a little more- This one is very good and not too expensive. With the better calipers you can put numbers to all your measurements, and it has the fringe benefit of being good for other stuff (like never again wondering what size a screw is).

For now, flip a chain around and hold a left side cutter back to back with a right side cutter and see if they are the same or not.

20210301_170306.jpg


When you're ready to move forward with your sharpening skills, look up progressive raker adjustment. The simple way requires a progressive gauge, the better way requires a digital angle finder, and the best way requires.... calipers! (It's real slow though.) I use the DAF most of the time, though I like to validate its results with the calipers once a chain or so.

Top to bottom, FOP-style progressive gauge, digital angle finder, dial calipers

20210301_170917.jpg
 
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GENECOP

Minister of Fire
Jan 31, 2014
734
Ny
Did you sharpen the chain? Every time I sharpen my own chains, my saw makes right turns
:)
 

Max W

New Member
Feb 4, 2021
17
Maine
Your stacked feeler gauges should be plenty good to measure cutter length. Calipers and angle finder surely would help a chain work at its best. I’ve always filed by eye along with a raker gauge. From what I can see on the 2 in 1 sharpener there is a flat file built in that takes the rakers down as you file the cutters. They should be ok if the cutters are the same and the tool is working correctly. I’m guessing that if you didn’t dull up you left side as you describe it, your filing may not be consistent holding your angles on that side. Hang in there it does just take practice.
.
 

jetsam

Minister of Fire
Dec 12, 2015
5,283
Long Island, NY
youtu.be
I use a 2n1 in the field, too, and you can screw up the rakers with it if you are not watching.

If you let the right rail fall off the right hand cutter and give it a good hard stroke, you'll lose a good amount of raker without touching the cutter.

If you put it on upside down, your square file sits on top of the cutter, so you won't be adjusting it at all.

In general though, it does a good job with rakers on new chains (because .025" is good for new chains) and a poor job on worn chains (because .025" is not good when the tooth is short).

Even if you do it right, raker height depends on the height of the next opposite-side tooth, so uneven tooth length will get you twice.
 
Dec 14, 2020
173
Lisburn, PA
I use a 2n1 in the field, too, and you can screw up the rakers with it if you are not watching.

If you let the right rail fall off the right hand cutter and give it a good hard stroke, you'll lose a good amount of raker without touching the cutter.

If you put it on upside down, your square file sits on top of the cutter, so you won't be adjusting it at all.

In general though, it does a good job with rakers on new chains (because .025" is good for new chains) and a poor job on worn chains (because .025" is not good when the tooth is short).

Even if you do it right, raker height depends on the height of the next opposite-side tooth, so uneven tooth length will get you twice.
I switched to a 2in 1 about 3 years ago. I used to hit rakers 2 strokes every second time I sharpened and sometimes I would go to far on the raker or not enough. I new how my 291 should cut and got pretty good guessing on taking some off the rakers. But the 2in1 puts me almost dead on every time. My eyes are going and even with the 3.5x readers I can't see well enough anymore to do the teeth and rakers by eye.
Question - why is .025" not good on short teeth? I have a chain that is sharpened down to mostly almost triangle shaped tops on teeth and it cuts just as well as my new chain. I sharpen each tooth and don't worry about keeping them same length as long as I get them sharp. Maybe I can learn something here.
 

xman23

Minister of Fire
Oct 7, 2008
2,352
Lackawaxen PA
It's the chain. Don't waste your time get a new one.
 

jetsam

Minister of Fire
Dec 12, 2015
5,283
Long Island, NY
youtu.be
I switched to a 2in 1 about 3 years ago. I used to hit rakers 2 strokes every second time I sharpened and sometimes I would go to far on the raker or not enough. I new how my 291 should cut and got pretty good guessing on taking some off the rakers. But the 2in1 puts me almost dead on every time. My eyes are going and even with the 3.5x readers I can't see well enough anymore to do the teeth and rakers by eye.
Question - why is .025" not good on short teeth? I have a chain that is sharpened down to mostly almost triangle shaped tops on teeth and it cuts just as well as my new chain. I sharpen each tooth and don't worry about keeping them same length as long as I get them sharp. Maybe I can learn something here.

Did you ever have someone tell you, "There's nothing like a new chain" and think he needed to learn to sharpen?

Well, he's actually right, if you always take the rakers down to 0.25" below the tooth.

I can't find a good picture on the internet, so here's a real life example from my workbench.


20210301_213209.jpg
Here's a fairly new cutter with most of the tooth length left.

20210301_213255.jpg
The old 0.25" raker gauge says this raker is way too low

20210301_213319.jpg

A FOP progressive says it is just about perfect, maybe a hair low


The calipers say the tooth is .505 high and the raker is .480 high, a difference of .035.
The calipers also say the distance from the tip of the raker to the tip of the cutter is .375.

Here is the triangle formed by the tip of the raker (yellow), the tip of the cutter (red), and the wood being cut (green).



20210301_213209.jpg


Solve the right triangle to get the angle of attack there. A new chain generally bites at 5.7°.

Screenshot_20210301-215648.jpg

So that raker is .035, and making a 5.3° angle to the wood.... lower than a factory chain at 0.25"!

I put the digital angle finder on it and got 5.5, so close enough.



Now add some wear to the tooth.


20210301_220611.jpg

Now the tooth is .490 high, the raker is .445, a difference of 0.045. It is 430" In a straight line between the point of the tooth and the top of the raker.

Screenshot_20210301-225027.jpg

So 5.9° , this raker is about perfect.

If this depth gauge was set at 0.25"....

Screenshot_20210301-225206.jpg

We'd be cutting at 3.3 degrees and making tiny chips and sawdust.

The upshot is that if you always keep your rakers at 0.25", you will be cutting at around 2° at the end of the chain's life- barely any bite!

Progressive gauges like the FOPs are a huge improvement but they still don't keep you at 5.7 by the end of the tooth.


Hope this made sense. It's all about the angle between the raker and the place where the wood meets the tooth! Small angle, little bite. Big angle, big bite. Big bite cuts faster; too big gets rough and is hard on the saw, chain, and operator.

Interestingly, and this makes sense, I heard a guy say that you can have teeth twice as long on one side than the other and still cut straight if all your rakers are set to the same angle. (Haven't tried it, want to.)
 
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Dec 14, 2020
173
Lisburn, PA
Did you ever have someone tell you, "There's nothing like a new chain" and think he needed to learn to sharpen?

Well, he's actually right, if you always take the rakers down to 0.25" below the tooth.

I can't find a good picture on the internet, so here's a real life example from my workbench.


View attachment 275613
Here's a fairly new cutter with most of the tooth length left.

View attachment 275614
The old 0.25" raker gauge says this raker is way too low

View attachment 275615

A FOP progressive says it is just about perfect, maybe a hair low


The calipers say the tooth is .505 high and the raker is .480 high, a difference of .035.
The calipers also say the distance from the tip of the raker to the tip of the cutter is .375.

Here is the triangle formed by the tip of the raker, the tip of the cutter, and the wood being cut. (I did the wrong color in the picture, .375 is the green line not the red one).



View attachment 275617


Solve the right triangle to get the angle of attack there. A new chain generally bites at 5.7°.

View attachment 275618

So that raker is .035, and making a 5.3° angle to the wood.... lower than a factory chain at 0.25"!

I put the digital angle finder on it and got 5.5, so close enough.



Now add some wear to the tooth.


View attachment 275620

Now the tooth is .490 high, the raker is .445, a difference of 0.045. .375" In a straight line between the point of the tooth and the top of the raker.

View attachment 275619

So 6.8°... this raker is actually a little aggressive but not bad enough that I'd file the tooth back to fix it.

If this depth gauge was set at 0.25"....

View attachment 275621

We'd be cutting at 3.8 degrees and making tiny chips and sawdust.

The upshot is that if you always keep your rakers at 0.25", you will be cutting at around 2° at the end of the chain's life- barely any bite!

Progressive gauges like the FOPs are a huge improvement but they still don't keep you at 5.7 by the end of the tooth.


Hope this made sense. It's all about the angle between the raker and the place where the wood meets the tooth! Small angle, little bite. Big angle, big bite. Big bite cuts faster; too big gets rough and is hard on the saw, chain, and operator.

Interestingly, and this makes sense, I heard a guy say that you can have teeth twice as long on one side than the other and still cut straight if all your rakers are set to the same angle. (Haven't tried it, want to.)
OK, I'm a few Premiums in after dinner, so please bear with me. How does "a" stay at .375 if the tooth is shorter?
 
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Dec 14, 2020
173
Lisburn, PA
As the chains get sharpened, I always end up with different lengths on teeth and one side is always a bit shorter, but if I keep all teeth sharp and rakers at same depth, my cuts are straight.
 

jetsam

Minister of Fire
Dec 12, 2015
5,283
Long Island, NY
youtu.be
So with the 2in1 as the tooth gets shorter, I need to take more off the rakers to get the right bite?

Yes, exactly, because the 2in1 always files the raker at the same depth below the teeth (assuming the next tooth is the same size, the bar rests on the next tooth).

A real simple way to get most of the way there is to use a fileoplate type progressive gauge- they are not perfect but they are real easy to use.

If you ever want to accurately check how your hand filing or depth gauge system is steering you, grab a pair of calipers and measure like I did above!

Like I said, the pole is at 5.7° because that's how they get ground at the factory, but maybe you have a smaller saw with a bigger bar cutting oak, and maybe 4.5° is going to work better for you. Maybe you have a titanium chain and a custom saw made out of an old motorcycle, and 10° will get 'er done faster. :)
 
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Dec 14, 2020
173
Lisburn, PA
Yes, exactly, because the 2in1 always files the raker at the same depth below the teeth (assuming the next tooth is the same size, the bar rests on the next tooth).

A real simple way to get most of the way there is to use a fileoplate type progressive gauge- they are not perfect but they are real easy to use.

If you ever want to accurately check how your hand filing or depth gauge system is steering you, grab a pair of calipers and measure like I did above!

Like I said, the pole is at 5.7° because that's how they get ground at the factory, but maybe you have a smaller saw with a bigger bar cutting oak, and maybe 4.5° is going to work better for you. Maybe you have a titanium chain and a custom saw made out of an old motorcycle, and 10° will get 'er done faster. :)
Thanks for the sharpening lesson. :cool:
I know what you mean about sharpening for different wood.
I wasn't trying to be a smartazz on the "a" length question but I did help my Rocket Scientist sister get thru differential equations.:)
I will pick up a progressive gauge.
 
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jetsam

Minister of Fire
Dec 12, 2015
5,283
Long Island, NY
youtu.be
Thanks for the sharpening lesson. :cool:
I know what you mean about sharpening for different wood.
I wasn't trying to be a smartazz on the "a" length question but I did help my Rocket Scientist sister get thru differential equations.:)
I will pick up a progressive gauge.

No, thanks for pointing it out, it was wrong and it would have confused everyone.

I spent 30 years being that guy who always said, "That's good enough to cut firewood"- but now that I quit saying that and started learning what a chain should look like, I spend a lot less time cutting firewood! No more leaning on the saw while it spits out sawdust.

I think you'll like that progressive. No difference on a new chain, big difference at the end of a chain.

I think fileoplate is gone but Husky still makes their style gauge.
 
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Dec 14, 2020
173
Lisburn, PA
No, thanks for pointing it out, it was wrong and it would have confused everyone.

I spent 30 years being that guy who always said, "That's good enough to cut firewood"- but now that I quit saying that and started learning what a chain should look like, I spend a lot less time cutting firewood! No more leaning on the saw while it spits out sawdust.

I think you'll like that progressive. No difference on a new chain, big difference at the end of a chain.

I think fileoplate is gone but Husky still makes their style gauge.
At our camp, we got a member who tries to cut all day with a dull chain!!!! It's painful! Poor Husky!
 

mtcox1791

Member
Aug 16, 2017
31
Upstate South Carolina
Update. Thanks for all the advice. Sorry took a while to get back but only have only have limited time to cut wood and work on the saw. I found a fair amount of variability in the length of my cutters. The trick of flipping the chain around to compare the cutters is pretty handy. I hand filed the longer teeth more with each resharpening. I also found that the rail height was different. The bar wound not stand up by itself on a flat surface. I hand filed the bar rails in my vice. It definitely cuts better. Again, I only notice it with with big rounds and I don't cut big rounds that often. Again, thank you very much.
 

maple1

Minister of Fire
Sep 15, 2011
10,809
Nova Scotia
My experience. Filing is only part of the issue. With a new bar and chain, if you get the filing off a little bit it will still cut straight. Up to a certain amount of wear. Then even a tiny bit of inaccurate filing will make it go crooked. Then it gets to a point where no matter what you do, it cuts crooked. Even with what looks like lots of tooth life left. That's because the other side of chain is wearing, along with the bar groove. Chain is sloppy in the groove and won't stay upright. When it gets to that point, time to start new again with both. For me. Sometimes a new chain will tighten things up enough, but most cases here, both are worn. Should be able to get 2 or 3 chains worn out with 1 bar, but trying to prolong bar life can lead to frustration with crooked cutting.

(That could likely all be lessened by cranking an adjustable oiler up. If you have an adjustable. The 250 is not.)
 
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salecker

Minister of Fire
Aug 22, 2010
1,534
Northern Canada
I got a 2x72 belt grinder for making knives last year
Bonus was it is great for dressing bars,you can get right in close to the sprocket tip with it.Makes truing the rails an easy task.Then a vice to squeeze the rails back together if they have got sloppy.
And then you have a bar that cuts straight and is good for a bunch more chains.
 

SpaceBus

Minister of Fire
Nov 18, 2018
6,270
Downeast Maine
My little Stihl MS 150 started cutting very noticeably crooked not too long ago. I spent a while today trying to get all those tiny cutters the same length, bar dressed, etc. but it still cuts pretty crooked. The 1/4" micro stuff is very annoying to deal with so I just ordered a new bar and a pair of chains. The little saw still throws chips, but anything over 3" diameter is a chore to cut and the cut end ends up looking like a potato chip. I wasn't as diligent as I should have been with flipping the bar and I'm betting the chains ended up wearing unevenly against the rails.