Have used chainsaws to cut firewood and pulpwood for many years, but have never experienced this:
Milled my first log today with my Logosol M7 csm.
It came with a Husky 395XP powerhead and a 20" Forester Pro Series bar by AEI (whoever that is).
The chain is a low profile Stihl, model 63PMX. The chain is .375 pitch, .050 gauge.
The 395 was a demo, so it was already broke in, but the bar and chain are new.
Before milling, I noticed that the chain was somewhat hard to pull around the bar by hand even though the tension was correct, but at the time I didn't make too much of it, thinking that it was just the roughness of the bar rails ( they still had paint on them). After I made a couple of cuts, I noticed that the chain had become fairly loose. I went to pull it a little by hand and it was quite hard to pull at first, then became somewhat easier, but at the same time, the slack disappeared.
I took the saw to the shop and after removing the bar and chain, I discovered the problem.
Turns out that the points of the nose roller were too thick to go between the side straps of the chain; each point was wedging itself between the straps as the chain went around.
Got out the ol' dial micrometer and went to measuring.
* chain drive link - .050 (as expected)
* between chain straps - .052 to .053 (as expected)
* bar groove - .060 to .061 (seems too wide to me)
* roller points - .057 to .058 (the very tip of the points are slightly beveled, that's how they were able to start wedging between the chain straps)
This Forrester bar is stamped "3/8 050 72DL"
Got out the old Stihl Farmboss firewood saw (which also has a roller nose bar) and did some comparing:
The Farmboss bar and chain are .325 pitch and .063 gauge.
* chain drive link - .063 (as expected)
* between chain straps - .065 to .066 (as expected)
* bar groove - .065 to .066 (as expected)
* roller points - .059 to .060 (as expected)
The drive links on the Farmboss chain are fully supported on their fore and aft edges by the roller, whereas the drive link edges on the 63PMX chain can't reach the roller due to the roller points hanging up trying to wedge between the straps.
To me, it appears that the Forester bar is not kosher.
Surely the roller is not designed for the points to be forcefully wedged between the straps and then forcefully pulled out again as the chain goes around.
Is this Forester bar a cheap junky import or what ?
Anyone else run across anything like this ?
Jim (retired and loving it)
Milled my first log today with my Logosol M7 csm.
It came with a Husky 395XP powerhead and a 20" Forester Pro Series bar by AEI (whoever that is).
The chain is a low profile Stihl, model 63PMX. The chain is .375 pitch, .050 gauge.
The 395 was a demo, so it was already broke in, but the bar and chain are new.
Before milling, I noticed that the chain was somewhat hard to pull around the bar by hand even though the tension was correct, but at the time I didn't make too much of it, thinking that it was just the roughness of the bar rails ( they still had paint on them). After I made a couple of cuts, I noticed that the chain had become fairly loose. I went to pull it a little by hand and it was quite hard to pull at first, then became somewhat easier, but at the same time, the slack disappeared.
I took the saw to the shop and after removing the bar and chain, I discovered the problem.
Turns out that the points of the nose roller were too thick to go between the side straps of the chain; each point was wedging itself between the straps as the chain went around.
Got out the ol' dial micrometer and went to measuring.
* chain drive link - .050 (as expected)
* between chain straps - .052 to .053 (as expected)
* bar groove - .060 to .061 (seems too wide to me)
* roller points - .057 to .058 (the very tip of the points are slightly beveled, that's how they were able to start wedging between the chain straps)
This Forrester bar is stamped "3/8 050 72DL"
Got out the old Stihl Farmboss firewood saw (which also has a roller nose bar) and did some comparing:
The Farmboss bar and chain are .325 pitch and .063 gauge.
* chain drive link - .063 (as expected)
* between chain straps - .065 to .066 (as expected)
* bar groove - .065 to .066 (as expected)
* roller points - .059 to .060 (as expected)
The drive links on the Farmboss chain are fully supported on their fore and aft edges by the roller, whereas the drive link edges on the 63PMX chain can't reach the roller due to the roller points hanging up trying to wedge between the straps.
To me, it appears that the Forester bar is not kosher.
Surely the roller is not designed for the points to be forcefully wedged between the straps and then forcefully pulled out again as the chain goes around.
Is this Forester bar a cheap junky import or what ?
Anyone else run across anything like this ?
Jim (retired and loving it)