Greenstar said:
this FREQUENCY OF REPLACEMENT is acting as something of a red-flag!
Hi Greenstar. Sorry I didn't get to answering your question, but here goes. I'll try to answer in enough detail, but possibly at the expense of offering too much overall in explanation.
First, 18 months on a bar is a good run for me. I am a commercial Arborist, the owner of the business and see a lot of continuous action. Unlike Austin1, who flushes his tanks at the end of the season with diesel (a good idea), I don't have an 'end of the season', just brief vacations. Winter is as busy as Summer and is often when I hire extra help. 50 - 60 hour weeks are the norm for most seasons but it goes down to about 40 in the Winter because of the shortened daylight hours. Just the sheer number of hours of usage has something to do with bar life. Maybe cycling between sub-freeze / operating temp does too.... I don't really know.
I claim to recycle every bit of every tree. This means chips get bioconverted back to soil, premium logs get milled into planks and a lot of firewood gets cut. The chips, it is nice to say, have only residual vegetable oil in them, so folks can handle them for landscaping, or be safely used for playground use of the bioconverted soil can be used for growing vegetables. Milling logs into lumber is very tough on a bar and chain.
I have a Bandit 6" chipper, meaning a 6" log is the maximum size it can take and if we're wise if we only chip 4" and down to conserve fuel and engine wear and minimize trips to get rid of chips. So what happens to pretty much everything 4 inch diameter and up ? Firewood. This may be laughable to larger companies with big chip trucks, big chippers, prentice or crane loaders and bigger crews but our efficiency (profit) is equalled by the fact that our equipment overhead is way low and I have guys standing in line to come and take the firewood. The tradeoff to the low overhead costs is that I have to make a LOT of firewood. Having a number of firewood recipients makes it so we don't have to handle the wood very much, maybe just toss it into a general area, but if I time their arrival just right I cut it and never have to touch it. However, I make a number of truckloads a week of firewood, forearm diameter and up, and this may be in part why I can't get two years out of a bar.
I cut the stubs off the downed logs and limbs flush with the log's surface. This is a bigger cut than leaving a stub protruding out past the branch collar. More cutting, but a higher quality end-product. It makes it so the firewood splits better and stacks better. My main firewood guys generally drop their duties and come get the wood when I call. In like, I make them the highest quality firewood of which I am able (they're in the business to sell it). More detail, yea, more cutting, but in the sense that they are helping me to help them, we all do what we can to make this system work. As a biologist, Greenstar, you are certain to understand what is meant by a beneficial, mutualistic symbiotic relationship.
Big rounds, too big for the firewood guys to load by hand I will cut lengthwise into fourths. Cutting
with the grain creates 'shredded mozzerella' sawdust. Big takedowns require a lot of firewood to be cut in the first place, and when I get into quadding these big diameter rounds it just makes for a lot of work for the saws. This could have something to do with bar life.
I hit dirt now and then like any of us. Sometimes I press on, rather than stopping and resharpening, depending on how bad, or what I hit, and how much daylight is left and how close I am to being finished when the chain drops in effectiveness. I like to think I'm a stickler for running a sharp chain all the time, but I'm nowhere near perfect in that department, though I am acutely aware of when the chain is too dull to move on. These moments of less-than-perfect sharpness could have something to do with bar life.
I run 8-pin, rather than 7 pin sprockets, giving a higher chain speed. This could have something to do with bar life.
My main firewood maker is a power-ported Husky 346 XP that I changed out the 7-pin .325 sprocket to an 8-pin 3/8 sprocket. I run 3/8 low profile chain and a smaller 14" bar, the same used on top-handled climbing saws. The reason is I have a higher-powered saw with 12,500 RPM top speed and a thinner kerf bar and chain is I want wicked-fast cutting of firewood since I do so much of that. I take advantages anywhere I can. The bar and chains are undersize for the saw. Bars this size, though, aren't that expensive and I buy chain by the 100-foot reel and have chain-making gear onboard in the field. I think this unconventional setup might have more to do with bar life than anything else.
I sometimes do plunge-cutting for creating mortise and tenons, or gargantuan dovetails, crafting occasional benches out of trunk/log sections. Not a whole lot, but I do get these requests now and then and if they're willing to pay my regular climbing fee I'll do whatever they want. I can blow a tip doing a plunge while the rest of the bar is fine. This can take a bar out early. Mini bars don't generally have replaceable sprocket tips, so you blow out the tip, you say goodby to the bar.
I cut stumps really low for the stump grinding guy. Often there is dirt pockets embedded in the convolutions of the buttress. Sometimes you go through them, the chain dulls somewhat, but you're still cutting, so you keep going, especially if it is the last cut of the day. This definitely creates accelerated wear on a bar.
Recently I had to dice up a bunch of piles of stacked brush out in some guy's woods. Stacks taller than me, he was wanting us to drag 5 of these piles out of the woods to be chipped. I politely declined, but offered an option to diminish the size of the piles from 8 feet tall down to two or three, leaving a compact area where he could continue to pile brush on top of into the future. This is very, very hard on a bar as all the branches and limbs are going all directions and your chain wavers left and right offering inconsistent pressure on the left and right bar rails as it passes through the tangled mess. You have to run your chain with extra tension, and still you're gonna pop the chain off now and then. Not recommended practice.
What else? I work in the rain and really don't mind it. If I can leave a crowned-out major trunk standing, poised for felling, and come back and fell and buck it up in the rain, this is a good use of time that I might otherwise stay home. This won't make sense to many, but with as heavy a schedule as I have, it sometimes makes more sense to clean up the crown, leave a pile of firewood at the base of the standing trunk and move on to other climbing duties while the weather is good. This maximizes profit, allows me to get to the next waiting client and come back to something I can do when it rains and climbing is less than ideal or less safe. I'm not sure, but using a saw in the rain
has to be harder on it, as well as tougher on the bar and chain. This could have something to do with bar life.
All things considered, I'm pretty thrilled if I get a year and half out of a bar. With a 14" bar costing hardly more than a 14" pizza, the comparative cost of 18 months of bar use compared with other expenses like 18 months of lunches, or 18 months of fuel mix, the cost of 14" bars (though we're not talking about money) is almost laughably low.
Back in my petro bar oil days it seemed like the life of a bar was not any different.
Right now I'm running a 12" titanium carving bar on the 346. Sizzling fast firewood cutting, a wee bit lighter overall.
As predicted, a whole lot of words.
I hope this answers your question.
It's all good.
