<font color="blue"> John, I have read many of your long-winded posts here and there and I can now agree that you have some great info with Sthil products and starting methods. </font>
Ummm - well hey wushaw .... thanks ... ermmm ... thanks for those uhhhh ... those mostly kind words. /forums/images/graemlins/laugh.gif
You remind me that I have on occasion been a little "spendy" with my verbiage - I'll see if I can tighten things up a bit. Remember though, the best steak has some fat on it. /forums/images/graemlins/laugh.gif
I used to use a grinder myself, the Oregon 251 that you might just have. I sold it for what I paid for it ($200) about 10 years ago, but you know what? After reading your post, I just decided to pick up another one for the sole purpose of salvaging chains that have had run-ins with rocks and can't realistically be brought back to life with hand filing. You know the ones I mean, rounded over about 1/8" and would take about 75 strokes per cutter by hand. /forums/images/graemlins/tongue.gif
I'm looking forward to posting a big, long treatise on chain, chain sharpening, bars, bar maintenance, and yes, even sprockets (woohoo!) (aka shprockets for my German-American friends out there). /forums/images/graemlins/smile.gif (SNL reference).
One of the biggies that will be stressed is that the cutter must be absolutely razor-sharp (well, close to it; knife-sharp?) in order to do its thing. Sounds obvious, but my point is that when/if you sharpen with a (fresh, new, great-cutting) file, you can't take a few half-hearted swipes at the cutter and say "OK, that's good enough". The entire leading edge of the cutter, but ESPECIALLY the very front point of the cutter MUST be absolutely sharp, or your chain will NOT cut well. This is especially true on a full-chisel chain, where the front point, the first part of the cutter that starts each cut, is more like a single point than on the slightly more (but not much more) forgiving leading edge of a semi-chisel chain, whose leading front "point" is actually an arc.
Once a cutter has been sharpened to the state, absolutely razor sharp, at the proper top plate angle (the angle that those laser-etched lines on the top of the cutter are at, 25-35 degrees depending on the chain model and/or mfr., but in a pinch 30 degrees will get you down the road just fine every time), with its rakers taken down to .025 (just fine in the vast majority of cases), and is running on a bar that is in good shape, it will cut like nothing you will have probably ever experienced before.
I say this because as I mentioned before, brand-new, out of the box chain typically has rakers that are set way too high. When we tune up a "new" chain its proper settings, the difference in performance is downright startling. So in short, I suspect that many users out there, (except you - that's right, you - you know who you are - you've figured it out and know what I mean) who by getting, and KEEPING their chains in this state will be cutting like they have NEVER cut before, even with a new chain.
And once your chain is sharp like this, KEEP it sharp like this! NO HITTING THE GROUND, NOT EVEN A TEENY LITTLE BIT! This will take the keen edge off your chain in ONE SECOND FLAT! It took me YEARS, yes YEARS to finally get this through my thick skull! A Samurai does not use his sword for digging in the garden!
Rocks and metal are of course the two mortal enemies of the chain. Rocks are the more avoidable of the two, and you have to be constantly vigilant to avoid them. Always be aware of what is underneath, or just behind that log or branch you are cutting. There is nothing more disheartening than to see all of your fine sharpening efforts get destroyed in a heartbeat in a dazzling display of sparks.. When you hit a rock, pretty much forget restoring it by hand. Maybe have it sharpened on a grinder, but remember that it will usually then be more difficult to sharpen by hand.
As for metal, be constantly on the lookout for it - old clothelines, eyebolts for hammocks, screws and brackets for light fixtures, any of the many things people attach to trees. And it's often found right inside the tree, long-since covered over by years and years of growth rings. Nothing whatsoever you can do about those hunks of metal, it's just the luck of the draw.
OK - just to review: get it sharp, keep it sharp, and when it becomes "wood dull" - i.e., the cutter doesn't look noticeably dull, but you can tell that the chain isn't slicing the way it should be, and you're having to exert just a little too much force to make a cut, or the chips aren't flying like they were .... STOP! .... the chain isn't going to get any better without a little action on your part. Just take your little rubber-rollered thingie, give each cutter as many strokes as it takes to restore a razor sharp edge (just 3 or 4 if you've been good), and it will cut like new (well, better than new) again. No need to take the rakers down each time, especially if you just give it a few strokes. You'll know when its time, it just depends on how much cutter you've filed away. But keep the chain sharp, heat is the enemy of bars, chains and engines. Don't struggle with a dull chain, it's a good way to get tired, frustrated, and then hurt.
Lastly, why do rakers have to be continually taken down? Notice how the cutter is angled downward from leading edge to trailing edge. As more material cuts filed away, the lower the leading edge becomes, relative to the raker. Keep that distance at .025, or very close to it, with a sharp cutter, and you're styling.
One final point. Yet another reason to keep the cutter razor sharp is that the part of the cutter that does the actual cutting is the chrome plating found on the very surface of the cutter. Wear that away, and you're cutting with the relatively softer metal underneath the chrome, wear accelerates drastically, and performance goes to he$$ in a handbasket.
Don't be like the woodsman who is so busy chopping down trees that he can't afford to take the time to stop and sharpen his dull axe! And as always, be careful with that thang.
