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050 v 058 gauge chains ...

Started by BC_coops, December 17, 2004, 09:35:47 AM

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BC_coops

I need to replace the bar on my limbing saw and am considering migrating from the US (3/8 x 050) to the Canadian (3/8 x 058 ) configuration.  It seems like my 050 chains are stretching out too soon, based on growth of sprocket wear relative to decline in cutter tooth.  That is to say that my sprockets are gone long before I've trimmed the cutters on a pair of chains even to half way to the end mark.

So I was wondering about changing over to the 058 Canadian option

(0) the 058 chains might accelerate a little slower, due to the heavier drive links, and "rewards" of kickback might be a little more severe due higher chain momentum when it happens

(1) possible longer life of the chain, due to less stretch.  Theoretically, there should be less pressure inside the drive link holes on the 058 chains ... the thicker drive link should give more surface area for the lugs on the tie straps to carry the running tension, and all the impulse accelerations that are happening.  Similarly, after champfering of an 050 drive link, there would be much less bearing surface, and thus the holes in the 050 drive links would "elongate," and the chain "stretches out" sooner.

(2) possible longer life of sprockets due to less "cutting of gooves" into the drive teeth ... the increased width of the drive link should provide more surface area for the sprocket tooth to pull it along.

(3) for deep cuts, the 058 chain might provide better cleaning of the bar gullet. For a given amount of cut, there is a given amount of cutter dust, and the greater volume within the 058 bar groove would give the bottom side of the chain a better mechanical advantage in cleaning out any given volume of oil mung (oil+dust) which tries to migrate down into the gullet.  ?-The chain would seem to run looser, when in fact it could be tighter.

(4) offsetting features - If the 058 bar is thicker-?? than the 050 bar (e.g. it both bars are made with same outer laminate, then the kerf on the 058 would be wider, and that might generate more waste and draw down on production.  On the other hand, the gullets of an 058 chain might "breath" better, and its waste might be cleaner, e.g. it might have larger chips.

(5) less bar pinch ... the main reason I prefer 3/8 chain to 325 for limbing.  The wider kerf of 3/8 seems to give me a little more warning of impending bar pinch when relieving compression in a spring branch (e.g. it is more foregiving).  Thus I seem to spend less time and energy working (yanking) the bar out of the few spring branches that occassionally (ha) "get me."  The wider kerf of a 3/8 x 058 should be even a little more forgiving (give me better warning) on relieving  limb compression, relative to the 3/8 x 050 or 325 x 058.

Any comments appreciated ...

Kevin

BC;
You have an issue but it isn't with chain gauge, seems more like the chain is too tight, too loose, the bar could be worn, or chain lube isn't sufficient.
If just one of these ... sprocket, bar or chain is worn  then all could be affected.
Damage one, you damage them all .

Lewis Brander

Kevin. Well said. If bar, chain, chain adjustment, sprocket and lubrication are up to par then the old rule of thumb should be to replace the sprocket after replacing the second chain after it wears out. If you're not keeping the chain sharp, not adjusting it porperly, using a worn out bar or sprocket and the chain isn't getting enough lubrication, then it doesn't matter what gauge chain you use, you will have the same PROBLEMS. Take care. Lewis.
My hobby is restoring old saw. Just because it's old, doesn't mean she can't run and look good again. Take care. Lewis Brander.

BC_coops

Thanks, guys ...

No doubt about it ... on the beloved saw in question, I finally decided to admit that the worm gear on my oil pump is way gone, and, I regret to admit, it gets even worse than that, as the main bearing at the flywheel end was also so worn that I could "clunk" the flywheel end of the crank around from the rear end of the bearing to the forward end.  (It didn't feel like perceptible motion, but nonetheless there was this barely audible "clunk" sound.)  I have the feeling that the crank may have gotten bent in a micro-millimeter way, when I hit a buried nail full on on an upcut.  I tried measuring runout on the shaft-- and got nothing, at the clutch end of the shaft only ... but nonetheless after that accident, the saw never really ran the same ... there was this barely perceptible increase in vibration ... I always thought maybe I had trimmed down my rakers too much ... 025 is just right for me.  When I recently dismantled the saw to try to repair the oil pump, that's when I noticed the clunk in the bearing at the flywheel end, so I probably should have tried to meausre runout there too, as I have the feeling that it was the bearing (or case) at the flywheel end of the shaft that "took the hit" on that nail.

So, my question would have been better framed as ... do I want to set up my replacement saw (say in 50-60cc range) with 050 or 058 chain?  I've been thinking along the line of Dolmar 6000.  I defninitely agree with your main point, well made, that if I put off basic repairs for too long, or if I take a major hit like that and just keep running the saw like nothing happened, it won't make any difference 050 v 058.

But, still, it seems that there must be some reason that saw manufacturers give us a choice of 050 or 058, but I haven't found anything in the literature ...


Crofter

The .050 and .058 chains are identical except the drive tangs are reduced to .050 where they enter the bar groove. Not until you jump to .063 chain do you get heavier elements in tie straps and rivets.
Frank

jakemi

Hello everyone,Im a newbie here and this was the question I was looking for. Need to replace mine also and I have .058 chain but all i can find is .050 without ordering it. Would  it cause any damage if i went smaller. Little bit more clearance in the bar?  What do you think?.  Its fits on a older Husky 55(1990 or 91). Just use it to cut firewood off of my property

Michael_E_Tx

Welcome jakemi.   I'm no expert, but I know what you have in mind is a bad idea.  About equivalent to putting new (right size) chain on a worn out bar.  If your bar isn't worn out now, it soon will be if you do this.  Too much clearance = tendancy to cut crooked, excessive wear to bar and chain, more sawdust/chips packing into the bar, less efficient oiling.

My question to you is what's wrong with ordering?  Try it you'll like it.  It's cheaper too.  There are several large suppliers that folks use.  In the past year, I've bought from Bailey's, Madsen's and CCD.  Painless everytime, delivered to my door (well, gate, hehehe) in rural E. Texas in just a few days.  Some folks who have a favorite good dealer, buy their chain from that dealer to support the dealer for having what they need.  I'm assuming you don't have one of those or he would surely get you some .058 gauge chain, it ain't rare in the chainsaw world.

If you've had your saw for some time, or got it used, consider treating yourself to a new bar, they are not very expensive either.  New chain, new sprocket, and new bar is a combination guaranteed to please.  Plus it will set in your mind how your saw cuts when everything is right.

Mike

BC_coops

On basic principles of geometry and physics (warning -- begin to liberal application of salt ... ), it seems that the stronger drive links of the 058 chain should last longer, all other things being equal, than the weaker 050 links.  There's more bearing surface for the rivits of the tie straps to transfer the stresses, and keep the parts "tight" and "lined up."  In addition to the 058 chain being stronger and lasting longer, the 058 bar should similarly be stronger (and a little heavier) and also last longer.  The wider bar will offer wider "shoulders" for the cutters to run on.  (The outer laminates of the 058 and 050 bars are the same, so the cutters "run" on the same "rails" for either bar.  However, the 058 bar is wider because the middle laminate e.g. the "gauge" laminate" is 059 v. 051, or whatever.)  Because the 058 cutters have wider shoulders to ride on, they should tend, all else being equal, to "sit up straighter" in the cut.  Thus the wider bar supports the cutter in its reaction against the side of the cut, e.g. against its reactive desire to "tip" inward.  When the cutters try to tip inward, they would pass a twist over to the drive link (left cutters twisting opposite to right cutters) which would tend to wear the tips the descenders down in the bowels of the bar groove (where the gag muck is).  The leading edges drive link descenders stay sharper and clean the bar groove better, and the bar lasts longer.  In a deep cut, the wider chain might offer more of a "flow channel" in the wider space between the left and rigth cutters, for evacuation of detritus out of the cut.  Thus, all else being equal, the wider chain would have a little less tendency to "gag out" in wet stringy stuff.

In Europe, the owner's manuals for the Dolmars (p17 of the 7300 for example) do not refer to chain "gauge" like we do.  In stead of gauge, they refer to the chain's "Driver element strength."  That might be something worth thinking about.  For their larger saws, Dolmar does not recommend 050 driver element strength, and they start at 058 for over 20".  For the race cutters amongst us, the 050 chain or even narrower, will be lighter, and will accelerate faster, etc. if you are into trading half-seconds for safety and durability.

I sent a question to Oregon tech staff a few days ago, but haven't heard back yet.  

(after all that, now I gotta go pour some salt on my head ... )


leweee

BC_coops    ...yah sort ...kinda like that ...but not Quite . your almost there :-X
just another beaver with a chainsaw &  it's never so bad that it couldn't get worse.

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