aggiewoodbutchr
Addicted to ArboristSite
A while back I posted this...
http://www.arboristsite.com/showthread.php?t=37090&highlight=gb+mill
Well, finally, I'm closer to finishing what I started. Before I get into the details of the mill mods, I must detour a bit and explain what brought about the sudden need to finish this project.
Last evening I set out to make a 24" square, 8' long oak cant for testing various ripping chains. I mounted a brand new GB 44" harvester bar with FX style roller nose and a brand new Woodsman Pro 3/8 ripping chain to the 084, put it on the mill and got to work. Things were going well; saw was set, rails were on the log, aux. oil flowing, raised rpms to get the chain moving, started the cut, full power, dug in. Made about 12" of cut and it all went to hell. I saw sparks shooting from the bar end out of the corner of my eye and immediately shut her down. Upon inspection I found that bar nose had come loose and cut into the mill about 1/2", wrecking the chain in the process.(Image 1 & 2) Actually, the bar had melted it's way loose from my "prototype" plastic bar mount. You may think that the plastic is to blame here but I have used this exact setup with my 72” bar and .404 chains many times with absolutely no problems.
After studying all the evidence, I was able to conclude that the root of the problem was a combination the FX bar nose and 3/8” chain. GB advertises that their FX bar tips will function similar to a sprocket nose but with the advantage of being able interchange 3/8” and .404 chains on the same bar. I found this to be only partially true after comparing the fit of both .404 and 3/8” chains of various manufacturers on a new FX bar tip. As you can see in Image 3, the .404 chain chassis is picked up clear of the rails as it should be to reduce friction. Not so with 3/8” chain due to it’s shorter drive link (Image 4). The result of this when I was milling was a tip that got very hot, very fast as you can see by the burnt paint (Image 5).
Continued…
http://www.arboristsite.com/showthread.php?t=37090&highlight=gb+mill
Well, finally, I'm closer to finishing what I started. Before I get into the details of the mill mods, I must detour a bit and explain what brought about the sudden need to finish this project.
Last evening I set out to make a 24" square, 8' long oak cant for testing various ripping chains. I mounted a brand new GB 44" harvester bar with FX style roller nose and a brand new Woodsman Pro 3/8 ripping chain to the 084, put it on the mill and got to work. Things were going well; saw was set, rails were on the log, aux. oil flowing, raised rpms to get the chain moving, started the cut, full power, dug in. Made about 12" of cut and it all went to hell. I saw sparks shooting from the bar end out of the corner of my eye and immediately shut her down. Upon inspection I found that bar nose had come loose and cut into the mill about 1/2", wrecking the chain in the process.(Image 1 & 2) Actually, the bar had melted it's way loose from my "prototype" plastic bar mount. You may think that the plastic is to blame here but I have used this exact setup with my 72” bar and .404 chains many times with absolutely no problems.
After studying all the evidence, I was able to conclude that the root of the problem was a combination the FX bar nose and 3/8” chain. GB advertises that their FX bar tips will function similar to a sprocket nose but with the advantage of being able interchange 3/8” and .404 chains on the same bar. I found this to be only partially true after comparing the fit of both .404 and 3/8” chains of various manufacturers on a new FX bar tip. As you can see in Image 3, the .404 chain chassis is picked up clear of the rails as it should be to reduce friction. Not so with 3/8” chain due to it’s shorter drive link (Image 4). The result of this when I was milling was a tip that got very hot, very fast as you can see by the burnt paint (Image 5).
Continued…
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