Mystery problem cutting?

[Scratch]

I'm using a Stihl MS362C with a 20" bar and a standard Stihl chain on it. I've sharpened it many times with a Pferd sharpener. I've used this exact combination for about 15 years and cut about 15-20 cords a year for home heating in my outdoor wood boiler. I'm not a pro. About 3 years ago, the city dumped 25 dump truck loads of green Cottonwood on my property and I've been slowly working at it along with other firewood. I know Cottonwood is not the best, but it was cut to 5 foot lengths, and delivered for free so I took it!

This year though I'm having a problem cutting. It's almost like my bar is too wide. The first 5-6 inches cut great into the wood. Lots of big flat chips, cuts fast, then it seems like starts to bind. The chain still spins easily but it seems like the bar is getting bound up. Every time I sharpen, I flip the bar, clean out the oiling hole, and file the edge burr off whenever I see it, but it still binds. If I do a plunge cut, it digs right in but will still bind up once I start going up or down with it.

This chain still has lots of life left in it, and I've tried switching to an older sharp chain with the same results but I'm thinking about trying a new chain because nothing seems to cut like a brand new chain.

The only thing I can think of is that maybe it's the wood. It has rained a few days straight recently and the water may have soaked in and made this Cottonwood swell making it bind easier?

Any other ideas?

 

[Muggs]

Sounds to me like you need a new bar.

 

[Reach]

I can see a few possibilities there. Could be you need a new bar, could be your chains are a narrower gauge than the bar is supposed to have. Another possibility is the oiler on the saw, if it isn't pushing enough oil the chain will bind. Also, could be the fibers in the wood are causing binding, I don't know enough about cottonwood to know if it has that tendency, we don't have true cottonwoods around here.

 

[Scratch]

Sounds to me like you need a new bar.

What could happen to the bar? I can see if I get a burr on the edges of the bar where that would bind, but I've filed the edges of the bar, in fact the last time, I was so concerned with the burr that I lightly used my 4" angle grinder with a 120 grit flap disc to make all edges of the bar super smooth. Other than the center of the bar becoming thicker on it's own, I can't imagine what a new bar would do. Maybe I'm missing something?

 

[Scratch]

I can see a few possibilities there. Could be you need a new bar, could be your chains are a narrower gauge than the bar is supposed to have. Another possibility is the oiler on the saw, if it isn't pushing enough oil the chain will bind. Also, could be the fibers in the wood are causing binding, I don't know enough about cottonwood to know if it has that tendency, we don't have true cottonwoods around here

Whenever I flip the bar, I always run the saw right over a fresh cut piece of wood to check if I get a line of oil spray coming off the chain. It looks normal to me. About the same that I usually see....

 

[Muggs]

What could happen to the bar?

The bar can get tweaked sideways just enough from hard usage that it won't run true. You won't notice it by eye just looking along the length, it will look fine. Easiest fix for the behavior you're describing is a new bar. I cut lots of poplar, there's nothing about it that makes it bind like that, least not that I've ever heard of.

 

[Bendroctanus]

Not sure if this has been said but along with dressing the sides of the bar for burrs, you also need to dress the rails. The chain tends to run it down particularly at the base of the bar by the dogs and sometimes at the tips depending on the length of the bar. This what the bar dressing file tool is primarily used for and it can make a big difference in your cutting. The bar dressing file will slide flush on the side of the bar so that it can file at a flat angle along the rails of the bar. Take the bar off and look down the rails from the oiling end and see if they’re worn.

 

[Reach]

Whenever I flip the bar, I always run the saw right over a fresh cut piece of wood to check if I get a line of oil spray coming off the chain. It looks normal to me. About the same that I usually see....

Like said above, the bar rails themselves need dressed much more than the burrs on the sides. We run our bars across a rail grinder at times, to true the rails.

Also, the bar groove can wear wider in time, causing the need to close it or replace the bar. We replace those bars.

 

[flushcut]

What could happen to the bar? I can see if I get a burr on the edges of the bar where that would bind, but I've filed the edges of the bar, in fact the last time, I was so concerned with the burr that I lightly used my 4" angle grinder with a 120 grit flap disc to make all edges of the bar super smooth. Other than the center of the bar becoming thicker on it's own, I can't imagine what a new bar would do. Maybe I'm missing something?

The bar rails themselves can splay open in time with heavy use. A bar rail closer might be the ticket.

 

[Evo]

All the previously mentioned reasons can cause this issue.

Some trees/woods will store tension and pinch.

Some inner bark will swell after it’s cut pinching the saw.

Trying to dress the rails with a flap disk is way too aggressive without proper truing.

Consider getting a 25” bar and chain of the same pitch etc. See how that cuts and deduce from there. If it cuts good it’s your old setup that’s the problem (which it likely is). You’ll be able to get the task done and figure out if you’re going to try to salvage your old bar/chain.

One rail worn or ground more than the others will cause the chain to list to one side with dramatic effect. This is my guess of what you have going on. A worn bar groove and that same list will still happen but in a more random pattern.

Bars can last a very long time, with minimal maintenance. It’s also possible your ‘over maintaining’ setting it up for human errors. I have bars that are on their second power head. I likely don’t cut near what most do here, but only really dress them as needed. Every so often I’ll run a flat file to knock the burrs and that’s about it.

 

[southsoundtree]

Bar pics up close to the trails will help.

A new chain will tell you it's your bar or its your chain.


Different wood will tell you if it's the spongy cottonwood.

Any j-cutting?

Wedging?