yep, here, just busy with family etc.
Ok, quick reply before going back to family stuff this season.
its pretty much the norm to run 880s and 25 or 20" bars with 404 semi chisel.
first for the durability that 404 and semi brings, also the slower chain speed of the 880's or other earlier series saws that is also very helpful in cutter edge durability with the harder dead euc's.
edited to add as distracted, the torque of the larger saws is needed too.
Also, its quicker to sharpen when you need to
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If its not self feeding as well as it should, look at the cutters edge again, some timber can be so hard it just knocks the edge off and your wondering why it wont feed.
Other times its just the timber and its odd grain orientation.
Another thing to consider is that the chain and bar rail groove can get worn, and allows the chain to cant over on an angle, the hard timber pushes the cutters away where as soft timber will just be cut. and that then makes the chain not self feed, and your wondering why its fine on one cut and move to a different part of the tree and its not self feeding.
So going further with that, you have a long bar, ie 42" + and the chain can wave not only up and down with harmonics like a wave, but also side to side, and one part of the chain cuts, other parts just passes over, eventually it starts to cut after you put a bit of pressure on it and make the cutters sit right.
Other times, the timber is just plain hard like iron, and no matter what you do, its going to be a struggle to cut thru it.
yeah chisel will cut thru it quicker, as the edge bites well, but its just not economical time wise to keep the edge of the cutter sharp with harder euc. Its great for green and felling notches as its easier to do the diagonal cutting compared to semi, but thats about it.
Keep the cutters sharp, less hook, dont worry about a large gullet, just make the top angle right, depth gauges right and smoothly rounded after setting their depth (helps with smoothness of cut), and keep the chain speed down and know that some parts of the tree where there is lots of different grain orientation, its just going to be harder/ slower, or the timber will release tension and move and you have to get the bar back out and start the cut again a few times to get thru it without it binding or canting the bar over in the cut.
but it burns like coal when its finally dry and ready to burn
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edited to add.
dont have any pics of the 404 handy, apart from some odd chisel stihl chain being made ready to cut green wood, so its got a large amount of hook, and not that good for this convo, apart from comparison, also I had to take out the gullet a bit due to improper grinder wheel setting from prior owner, depth gauge yet to be done. its not standard RS, but an odd ball sq ground chain I was repairing with a round file.
I think its RSLF going by memory.
here is some carlton (old stuff) 3/8 semi using 5.5mm file with a husky roller guide, gives a higher file placement, thus less hook, works really well on hard stuff, cuts well, druable edge, often when a chain gets to this cutter length, you can go to a smaller file to give more hook again due to the cutters reduced height on the green or soft stuff, with hard, its better like this.
Chain has cut a bit in this picture, i use a progressive file guide for the depth gauge, and round over the leading edge.