Ideal chainsaw bar length in regards to wood diameter.

[Drewman]

Pardon if this has previously been covered but I have tried searching and have come up wanting more information.

Is there a general rule of thumb or mathematical reasoning, or basic logic that I am lacking, to determine the ideal chainsaw bar length to use based on the diameter of the log being cut or bucked.

For example: One has a 16 inch bar (we will assume 2 inches is used up by the bar nuts) which only has 14 inches of cutting length. For a one pass buck cut or cookie cut, the maximum log diameter would be 14 inches.

Assuming the saw body remains the same (an MS290) would a 16 or 18 inch bar cut this more quickly, in theory.

Obviously the 16 inch bar would probably turn a bit quicker since it's shorter but it may bog down since 100% of the cutting area would be used up? Or would an 18inch bar be a slight quicker since it has 2 extra inches sticking out the other end, possibly cooling or oiling or something to improve efficiency.

Any thoughts?

 

[owingsia]

well its all up to you.... What I mean is what size saw do you like? This will also limit the size of wood you can cut....

1. smaller bar saws have smaller engines (Unless you buy a big saw and put a small bar on it). This means that the speed or power they have will be limited or for example I run a 16 in saw because anything I can harvest with a 16 inc saw I can safely handle on my own. (Personal taste plus anything I can cut down or buck with my saw I can split by hand)

Now when I am cutting bigger wood were the 95% of the bar is cutting... well lets just say it can bog down a bit!

Take into account my friends 30 inch bar on a 80 something CC engine cutting 28-29 inch logs and it just rips through them.

The bog down factor has more to do with engine power than bar size.

Example my little saw can accept a 20 inch bar... it however does not have the power to cut a 18 inch log....

If you need to cut large logs get a bigger saw. If you are like me and want to be able to easily handle the logs, trees, rounds whatever on your own without breaking your back then get something smaller. I am very happy with my little saw as most of what is in my woods I can take with my saw.... that being said some of the bigger stuff takes either back breaking work or many people and during those cases I have my buddy and his huge saw and other tools he uses every day on the job... He haw a 20000 pound winch that can pull just about anything out of the woods that he wants too.

OK anyway bar size has nothing to do with the engine bogging down, its the engine size that affects that. Example put a 14 inch bar on a 55cc engine and it rips though full bar length limbs with ease!

 

[Drewman]

I have a Stihl MS290 with 18bar from the factory that needs replaced. I was thinking of down grading to a 16in just for a little weight savings plus my large trees are over 18 inches so I will be making two cuts either way...thanks for the advice!

 

[owingsia]

If you are going with bigger trees that will take two cuts... you want more power not less..... get either the same saw.... well get a bigger saw... My 16 inch stihl could do a two cut take down.... I would never recommend that however for safety reasons. Double cuts imho you need a 20 inch 50+ cc engine....

 

[jeffesonm]

60cc saw with 20" bar

 

[BigCountryNY]

I'm extremely happy with my 60cc saw with 20" bar. I also went with a pro-model saw for a couple of other reasons too. It gets up to speed faster (great for limbing) and it's built to withstand constant use, provided you maintain it.

 

[claydogg84]

I say get 3 saws and put 3 different size bars on them

 

[Fred Wright]

Could be wrong about this ~ read somewhere on a state forestry website that your bar should be no less than 2 inches longer than the diameter of the log you're cutting. Probably for safety's sake, I'm guessing. Lowers the chance of kickback.

Large saws with longer bars are essential for speed when felling trees. For bucking firewood and limbing, it probably ain't all that critical. We've bucked a few that were larger than the 18" bar we have. It takes more time but we got it done.

 

[heavy hammer]

Big saw more power easier to cut through big wood still 660 or 066 little less than 92 cc 25 inch bar for small stuff 36 inch bar for big stuff best saw for power to weight ratio ever have an 880 but it's a beast to much saw until your cutting over four feet diameter wood plus really expensive

 

[EatenByLimestone]

I have a 290 and have 2 bars for it. 16 and 20 inch. I've used the 16 with a chisel chain on it for 99% of my cutting. I can bury it without any issues and it'll keep pulling. The 20 is used for felling larger trees. Always use a short bar if you can. It's harder to cut rocks with.

 

[TreePointer]

You can cut most logs with most any saw. It just depends on skill level and time you have to complete the job. It's nice to have bar length that is more than log diameter and the power to pull the chain (whether full comp, semi-skip, or full skip chain), but it's not necessary, and even professionals don't always have this luxury.

Sure, it's a bit safeER not to have the bar tip buried in wood, but that goes back to skill level. An experienced sawyer can do this without incident.

 

[Drewman]

...read somewhere on a state forestry website that your bar should be no less than 2 inches longer than the diameter of the log you're cutting. Probably for safety's sake, I'm guessing. Lowers the chance of kickback.

THANK YOU.

This was the response I was looking for. That seems reasonable from a safety standpoint as less chance of hitting something and causing kickback.

My dilemma is that my 18 in bar on my saw is getting pretty warn and I am not sure if I should go with an 18 or 16 inch. I do like my 18 and with my muffler mod and sharp chain it only bogs down if I am leaning too much into it when bucking, when I should be letting the saw do all the work. I rarely fell a tree as most of the stuff I cut falls down on it's own. I have 15 acres and am still harvesting the trees that fell this past year. I think I'm going to stick with the 18 for now and one of these years I'll ask for a 16 inch for a Christmas or Birthday.

 

[TreePointer]

There are what many consider sweet spots for given displacement. One definition for such is the longest bar can be buried in your typical wood yet not bog down too much.

My sweet spots:
50cc = 16", .325 pitch
60cc = 20", 3/8 pitch

Now, this is always tempered with specifics. A Stihl 261, for instance, is a strong 50cc class saw that has no trouble running regular 3/8 pitch chain on an 18" bar, while a Husqvarna 450 is better suited with .325 pitch chain on a 16" bar to meet the "sweet spot" definition above.

The 55/56cc midlevel saws (like the Stihl 290) are more of a crossover area in which a 20" bar is a little long when buried, but many don't bury it often and prefer the reach. Personally, I like saws with reach, so I'd go with the 18" bar over the 16" on a 290.

For the record, I owned a 290/20" (.325, .063) for a while, and 20" was certainly too long when buried in oak.

 

[Highbeam]

For any given log diameter, the same number of saw teeth will be engaged in the wood no matter how long the bar is. Assuming of course that your bar is long enough to get through the log in one pass. As such, when cutting a 12" log, the saw doesn't know if you are using a 14" bar or a 20" bar.

We have big wood in the pnw. I use the cut it 3/4 through and roll to finish method on the ground. Nobody likes to bend over all day so I use a 28" bar since that was the length of bar that would make it to the ground without me bending over.

 

[D8Chumley]

There are what many consider sweet spots for given displacement. One definition for such is the longest bar can be buried in your typical wood yet not bog down too much.

My sweet spots:
50cc = 16", .325 pitch
60cc = 20", 3/8 pitch

Now, this is always tempered with specifics. A Stihl 261, for instance, is a strong 50cc class saw that has no trouble running regular 3/8 pitch chain on an 18" bar, while a Husqvarna 450 is better suited with .325 pitch chain on a 16" bar to meet the "sweet spot" definition above.

The 55/56cc midlevel saws (like the Stihl 290) are more of a crossover area in which a 20" bar is a little long when buried, but many don't bury it often and prefer the reach. Personally, I like saws with reach, so I'd go with the 18" bar over the 16" on a 290.

For the record, I owned a 290/20" (.325, .063) for a while, and 20" was certainly too long when buried in oak.

That's some good advice Tree Pointer. I also had the same 290 set up and agree. My MS 460 rips ass with a 20" bar however

 

[TreePointer]

My MS 460 rips ass with a 20" bar however

Heehee! 70cc + 20" bar =

 

[cheeze]

You can cut most logs with most any saw. It just depends on skill level and time you have to complete the job. It's nice to have bar length that is more than log diameter and the power to pull the chain (whether full comp, semi-skip, or full skip chain), but it's not necessary, and even professionals don't always have this luxury.

Sure, it's a bit safeER not to have the bar tip buried in wood, but that goes back to skill level. An experienced sawyer can do this without incident.

I am presently cutting a red oak that is 51" in diameter. I'm using a Mcullough 4-30 with a 30" bar. Problem I'm having is trying to keep in line with the cut on the opposite side. Wondering if there is a "special technique" that works best for this kind of situation. I have been cutting all the way down on one side then going to the other side to make second cut. Trying to keep both cuts in line with each other is very hard to do and creates much more work. Any suggestions?

 

[2broke2ride]

Holy crap, a 4-30 is a museum piece, you must look like the hulk after lugging that beast around lol
Sorry, I'm no help with your question though, but love me an old McCulloch[emoji106]

 

[Oldman47]

Go back to the beginning. A 20 inch bar does not measure 20 inches overall. It exposes about that length to cut wood and ignores the part near the saw motor, drive sprocket and clutch. That means that a 20 inch bar will always cut all the way through on an 18 inch log or tree without getting you in trouble with things like kickback caused by the tip being buried.
To cut accurately with a saw near half the diameter of a tree or log, walk to the other side and begin the second cut by inserting the bar tip into the cut you have already made. Then you can just walk it back to a place that you set the end of the cut. You are continuing a cut, not starting a new one.

 

[Drewman]

I agree with Old man47. Continue a cut. However you need to do it up top on the exposed edge try to continue the cut around the log. That's just a really big log and I have little experience with something that large....

 

[klxrelic]

Most of the wood I cut is rarely over 12 inch diameter. The only reason I prefer 18" bar over the 16", is that I dont need to bend over so far when it comes to de-limbing the tree when on the ground, Its only two inches, but I can really tell the difference. Spruce has a lotta limbs, so yeah, it is noticeable