Modify my new bar?

Michael_E_Tx · February 03, 2004, 08:19:03 PM

I recently bought a used Stihl 036 Pro. Bar, chain and rim sprocket were worn out.

I replaced these items with a new Oregon rim sprocket assembly with a standard 3/8-7 rim sprocket, a new bearing, a new Oregon 20" Power Match Plus bar and a couple of loops of Oregon round chisel 72LG chain.

Man, I love this saw, runs like a top and cuts really well. Now here is where my question comes up

After only 3-4 hours cutting time, when I went to clean the bar and sharpen the chain (I flipped the bar for the first time today), I discovered that there is possibly significant wear, right at the tail end of the bar on the upper side. This wear is approximately 1/32" deep and about 1/2" long.

It appears to me that the bar is cut a little wide on the sprocket end, and that perhaps it would be good to take a file to it right where it is already worn in and level it at least to the wear level and perhaps even a little farther?.

I am a novice at such things, this is the first new bar I've ever bought. Maybe this wear is expected and helps the chain always center on the bar. My concern is, it seems to me, the current setup might result in unnecessary wear on the bottom of the drive links and tie bars of my chain.

This is my first "real" saw. I have a Stihl 021 that I've used for pruning and trimming for about 10 years, but the bar has never shown this type of wear at the sprocket end. It has worn extremely uniformly.

I might add that after I assembled the new bar and chain on the saw, I turned the adjustable oiler to maximum and added additional oil to the chain and bar for the initial run in. I also bide by the convention of raising the nose of the bar when adjusting the chain.

Any advice and/or opinions would be greatly appreciated.

qatanlison · February 04, 2004, 03:09:00 AM

Did you tighten the chain according to Oregon?
It sounds as you've been running the chain too loose.
Lift the bar up at the tip, tighten until the chain firmly contacts the underside of the bar, then add another quarter of a turn. That is if it's a bar with replaceble nose... Tighten the rear bar-bolt first.
The bar-rails are supposed to be a bit wide-cut at the end.

Good luck,

Ola

Michael_E_Tx · February 04, 2004, 09:33:28 AM

Qatanlison, thank you sir. I most definitely was not tightening the chain according to Oregon. I have since read thru the Oregon Maintenance and Safety Manual. You are correct about my bar being a replaceable sprocket nose bar. I had never even heard of the "snap" test mentioned there.

I have definitely been running the chain too loose. I have basically been following the procedure Oregon describes for a hardnose bar.. And then after the chain warms up, have been hesitant to tighten it enough to take the slack entirely out, even if the chain has cooled, such as when refueling.

Well, I'm going to stop fretting about my bar, tension my chain properly and get back to cutting.

Thanks again,

Mike

Kevin · February 04, 2004, 10:27:08 AM

A sure way to test the slack is to lift the chain from the bar.
You shouldn't see the very bottom of the driver when the chain has proper tension.

qatanlison · February 05, 2004, 12:34:39 AM

Mike, don't tighten the chain while it's warm! When it cools down and shrinks, the tension might be too much for the drive sprocket and bend the crank-shaft! Let it cool down first, the proceedure for tightening is for a cold chain, so that when warm, it'll get the right tension...
When the chain is new, let it cool and check tension every half tank of gas or so. (If you're bucking hardwood with long bars, more often) If you've tensioned the chain properly, when cool, there shouldn't be any slack when warm, and the chain shall certainly not hang on the "gut-side". The saw takes very much beeting from a poorly tensioned chain as does the chain and bar so tension IS important - and then there's the safety aspect...

Again, good luck with that new saw of yours!

/Ola

jokers · February 05, 2004, 02:20:47 PM

Hi Qatanlison,

I`ve never seen solid evidence of any crankshaft being permanently distorted by leaving a chain tensioned, but you may end up with crank seal damage from the seal being compressed on one side as the chain cools and contracts. This would be the reason why you are supposed to release the tension on the chain when you are done cutting for the day. Chains should be tensioned throughout the day as necessary whether they be warm or cold, but having to retension too frequently means that you are running dull chain.

Proper chain tension is as Kevin stated. You can pull it up far enough that you can almost see the bottom of the drive tang. It`s fine if it sags a little off the bottom of the bar, maybe a dime`s thickness, as long as you have good tang engagement in the groove. More tension offers no benefit and robs cutting power. It also limits the porpoising action of the cutters which results in slower cutting. One benefit of a belly bar on a race saw is to have the bar contour mimic the drape of a loose chain supported off the nose, but the average guy would be having chain throws with that little amount of tension for everyday work.

Lifting the tip of the bar while tensioning is also important to place the bar in it`s normally stressed cutting position and then tighten the back nut first.

Russ

oldsaw-addict · February 05, 2004, 02:49:47 PM

I had a saw that I was ALWAYS retensioning the chains on when I was using it, I found out after a lot of thinking about the problem and a little experimenting, that I needed a chain tensioning screw set on my saw. I was running an Echo cs-3000 with a 14" oregon intenz type guide bar with the crappy bar mounted adjusting system that is built into the bar, I had to accidentally break off a bar stud and ruin about 6+ sawchains before I realised that the problem was not dull chian of anything like that, it was the bar, it had no locking mechanism to keep it from sliding back on the saw and letting the chain go slack on the saw but not stretch very much. the moral, DONT buy oregon intenz bars.

jokers · February 05, 2004, 02:56:18 PM

Hi Oldsaw,

My understanding of the Intenze system is that you lift the tip of the bar and turn the adjusting screw until it feels like it`s locked up, then tighten the nut. If you simply adjust tension as you normally would on a saw with a tensioner, it won`t hold.

Your`s is a common complaint.

Russ

SasquatchMan · February 05, 2004, 05:12:43 PM

I noticed some wear right near the sprocket on my new bar after just a bit of cutting, and I think as qatan said, they're just a tad fat there... I haven't noticed any more wear with significantly more cutting.

Kevin · February 05, 2004, 05:19:11 PM

When I bought my Husqvarna 335 that was one stipulation.
They remove the Intenz system and put the original parts back in.
I was concerned about water getting into the bar and freezing preventing tensioning.

qatanlison · February 06, 2004, 12:23:40 AM

Jokers, I've never really though it possible for the chain to actually have the power to bend the crankshaft, but some technicians still says this can happen. On modern saws the shafts tend to be very stout so I doubt the bending theory as well... But I don't agree it is allright for the chain to hang a dime-thickness, the wear on the underside of the nose, when cutting with the belly and upper side near the sprocket, when back-chaining, will increase as the slack will be more than a dime here as the slack on the rest of the bar will be eliminated by the pull of the engine. But then again, a chainsaw is one tough tool, built of tough materials and will probably work under more abuse then some minor slack in the chain...

/Ola

jokers · February 06, 2004, 03:04:04 PM

Hi again Qatanlison,

I agree that too much slack in a chain will give accelerated wear behind the tip, but in my experience a dimes thickness in the middle of the bar is not a problem. Back in my younger days when I was prone to run dull chain because I didn`t know any better, I would have chains that drooped far enough for the tangs to no longer engage the bar. That`s when I first learned about this type of wear.

I`ll venture a guess that if we were side by side, our set ups would not be that much different.

Russ

Blue9R · February 07, 2004, 10:07:51 AM

Qatanlison,

The practice of placing a dime between the edge of a tie- strap and the bar to set cold chain tension has been around for a long time in the U.S. I have a 1984 Homelite manual with a rather nice illustration showing a dime used in this manner.

In the States, a dime is .050(1.3) thick, so this is the amount of gap we are talking about.

What is the common practice for setting cold chain tension in Sweden?

Mike

Blue9R · February 07, 2004, 11:01:38 AM

Let me try & post a pic of the diagram in the 1984 Homelite Manual.

Mike

Kevin - Does this bump up against any copyright issues?

Kevin · February 07, 2004, 03:19:07 PM

You're ok with that Mike, thanks.

qatanlison · February 08, 2004, 03:50:59 AM

I've never heard any good thumb-rules about chain-tension in sweden. Each and every logger seem to think his tension is the best and so on. But the most common one is to tighten it until it firmly contacts the belly of the bar. As the most common bar-lengths are up to 18" it does not take much tensioning to get the chain firm all along it...

/Ola

tony_marks · February 11, 2004, 03:49:38 PM

if u went strait power match with saw sprocket bar an everthing this may not apply.. but i do know that stihl sprockets are not quite the same as the power match... u canhold an power match
325 sprocket and an stihl sprocket fot my 026 and see that while the power match is close .. its not close enough to suit me.. either a thing fits or it dont.. and the powermatch was bigger..
which i think will wear everything out quicker..
edit on thinking about it .. i believe u may find the power matc sprocket is where u will find to much play,, when put on your stihl saw..i did..it was a reallesson for me..

kenskip1 · February 11, 2004, 04:47:47 PM

ola, Is that A Stihl in your picture? And you being from Sweden. The picture is small, and I may be mistaken.
Ken.Snowy NY.

qatanlison · February 12, 2004, 12:32:27 AM

Ken, the saw in my icon is a Husky 385XPG with a 28" bar.
As a Swede you wouldn't want to go with anything else than a Husqvarna... Hope you don't think less of me for that ;)...

/Ola

jokers · February 12, 2004, 02:22:41 AM

"As a Swede you wouldn't want to go with anything else than a Husqvarna... Hope you don't think less of me for that ..."

Well I certainly don`t Ola, the only reason that I could think less of you is because you`re not Norwegian, but then not everyone can be this lucky,

.

Russ

kenskip1 · February 12, 2004, 06:28:46 AM

Russ,
Are you Norweigon? I thought that I was the head Viking in this crew. You Have my name. Ken

qatanlison · February 12, 2004, 09:41:52 AM

Actually, Russ, I'm a descendant of Norwegian Vikings who came to sweden through Ireland, Scotland, Germany - Sweden. Does that sound better?

/Ola

jokers · February 12, 2004, 10:02:33 AM

Yes Ola, that sounds much better. It sounds as if you and I share to some extent, an ancestral heritage considering the adventures that they undertook.My great grandfather hailed from Bergen and great grandmother came from Sweden. They came to the US as young adults at which point my great grandfather began a distiguished career in the US Navy. Sadly I was too young to care where she was from when she was alive and my father doesn`t know either.

My surname, Christensen, ending in "sen" shows Danish influence also, which isn`t surprising given the history of the region, although my family goes way back in Bergen.

Ken, I made note of your name and assumed that you would have seen mine in the e-mail. I guess this means that there are atleast three of God`s favorite people, Scandinavians, on this forum. ;D

Russ

tony_marks · February 12, 2004, 05:14:28 PM

well my mothers maiden name was henson.. a shortened johansen im told..theyalso have allpassed on.. just learned the johansen pt prior to my aunts passing away..i do know the family story goes that some hensons got ina feud .. one faction started spelling it hinson..boys will be boys,,i guess..
kinda reminds me of a time some fellas come here wanting me to sellum some papers,, so they could breed thier dog[pit bull] an register the pups..i gaveum some.. dont know how their endeaver turned out but since the papers was on an old english shepherd dog.. i spect they run into a little trouble..