How Big of a Bar?

[n1st]

For 90% of the trees I cut, an 18" bar is fine. But once in a while, I'd like to cut thru 30"+ with one pass. Is it possible to use, say a 36" bar on a 50cc saw? I'd be in no hurry, so I could take it slow if that would prevent the saw from bogging down.

 

[Eric Johnson]

The longer the bar, the lower your power output. It makes a big difference. There are ways to cut trees over 36" with an 18-inch bar, so for the occasional tree, it's not required.

My dad always says, "If your bar is never too short, it's always too long."

Most consumer saws are sold with bars that are too long. A 16" bar is more than sufficient for most users. If you can get away with a 13, it's even better. Longer bars not only rob you of power and put excess strain on your saw, they need longer chains, and thus more work to sharpen and more cost to replace. Hey, I could go on. You stand a much greater chance of hitting something and dulling your chain with a longer bar.

 

[kevin j]

+1 on the shorter bar.
50cc would be way low powered, a 36 bar would typically be on 70 to 100 cc.

Lot more friction and also cutting forces. You'd have to use skip chain to pull it. It's not just the time factor, but the number of teeth that are cutting. The chips are sort of defined by the raker depth gauges, so can only pull half as many teeth.

And likely the oiler would not supply enough. The chain pins get the same amount of oil per tooth passing a spot, but the sprocket nose and bottom of bar have to get oil from the oiler, then all along the top run, than along the bottom run back. Wood soaks it up and just not enough volume for that much bar.

I looked at a 30 inch bar for my 50 cc saw for a one time job, but all the advice was not to do it. Tried a 24 and it was underpowered.

k

 

[TMonter]

On most 50cc saws unless it's woods ported I wouldn't go over 18" and would recommend 16".

For 20" bars a 60cc saw seems about right and for 24"+ you need at least a 70cc class in my experience to be happy with performance.

 

[n1st]

Ok, you talked me out of it. Thanks.

 

[downeast]

The longer the bar, the lower your power output. It makes a big difference. There are ways to cut trees over 36" with an 18-inch bar, so for the occasional tree, it's not required.
My dad always says, "If your bar is never too short, it's always too long."
Most consumer saws are sold with bars that are too long. A 16" bar is more than sufficient for most users. If you can get away with a 13, it's even better. Longer bars not only rob you of power and put excess strain on your saw, they need longer chains, and thus more work to sharpen and more cost to replace. Hey, I could go on. You stand a much greater chance of hitting something and dulling your chain with a longer bar.

Right Eric. All of the Northern European loggers use very short bars from 13" to 18" tops.
First, learn the techniques of safety ( PPE Nazi here ), sharpening your chain, wedge use, and HOW to fell safely.
Look up the Game of Logging ( GOL ) programs , or a CPL ( Certified Professional Logger) course in your region. Worth the time.

I've finally settled on a 16" bar on a small 50cc MS260 Stihl saw, from 28" and down with big saws, for all my cutting. The 16" will do + 3' DBH hardwoods with the techniques from GOL or CPL training. Not more work, and safe.

 

[downeast]

Not an issue Shorty. I cut just fine with plunge or boring into big wood, who knows how much power gain. The timber gets cut.
Goodbody gets a workout, the stoves get fuel, the pulp gets to the mill, the TSI gets the woodlot looking pretty.
I do use Stihl non-safety chains, well sharpened always. It's simple to learn how to touch up the chain on site with a Pferd sharpening system and a stump vise.
And always, always use your full PPE and your brain.

 

[Gooserider]

The rule I've always seen is 3-4cc of engine per inch of bar - my 36cc Pull-on was a peice of crap with the stock 16" bar; I put a 12" on it and it's a reasonably good cutting saw.

W/ my Dolmar 7900, (80cc) I normally run the stock 20" bar, which gives an effective 18" bar length due to the very large and aggressive bucking dogs on Dolmar saws... With the 4cc per inch, it cuts like a hot knife through soft butter - sometimes it feels like you dropped the saw through the log. Dolmar reccomends up to a 32" bar for the saw, but that would be pushing the ratio at 2.5cc/inch - the saw would probably do it with no problem, but I got a 28" bar for big wood (2.9 cc / inch) since that is pretty close - haven't had to use that bar yet but will see what it does when I do.

For a 50cc saw, I would say a 16" bar is ideal (3.125 cc / inch) or possibly an 18" (2.8 cc / inch) If it was a pro-grade saw, and had agressive bucking dogs that gave a lot shorter effective working length, I might go with a 20" but certainly no more than that.

Gooserider