Bad steel on a Stihl bar??

[Ed*L]

I was servicing my ms192t last nite & noticed the rail surfaces on the bar where the chain rides were very rough & pitted. I ran my thumbnail down them & there is a definate texture to them. There doesn't apperar to be any excessive wear on the rails.
This is a new saw with only 8/10 tanks of fuel thru it. The oiler is working properly & I'm using Stihl bar oil. It's a 14" bar with Stihl picco micro chain, not the narrow stuff. I haven't abused it in any way, I've only sharpened the chain once.
I'm thinking the rough surface will probably impact the chain life.
I haven't taken it back to the dealer yet, probably next week.
Just wondering if anyone has seen this before and opinions on it.

Thanks,
Ed

 

[tek9tim]

Hmm... 8-10 tanks of fuel and only one sharpening? Hmm... Do you have a solid bar, or is it laminated? What is your chain tensioning method? Seems most people run their chains too tight. None the less, it seems pretty early for problems like that to develop.

 

[Four Paws]

Hmm... 8-10 tanks of fuel and only one sharpening? Hmm... Do you have a solid bar, or is it laminated? What is your chain tensioning method? Seems most people run their chains too tight. None the less, it seems pretty early for problems like that to develop.

No sag - no drag! Should rotate freely by hand, and snap back to the bar. You shouldn't see the bottom of the drivers when lightly pulled down. IMO, tighter is better than loose! Loose chains will destroy the bottom of the tip in a hurry - not to mention they are dangerous!

 

[ShoerFast]

Too tight or to loose and the chain is chattering?

With out a picture, it may be that the bar-rails are just not work hardened yet? As they seem to wear into condition, maybe swapping chains for some time just to see if you get the same heel ware on both chains?

Anything can happen with heat-treats and run-ins (brake-in periods) keep us posted!

 

[Ed*L]

Guys,
I haven't had any problem with the saw chattering while cutting.
The bar is a Stihl rollomatic E standard.
I do keep the chain properly tensioned. You can't see the drivers when lightly pulled down.

The pitting reminds me of porosity that sometimes shows up when you machine cast parts.

I'll try to get a pic of the bar tonite, don't know if my camera is good enough to get a good pic. Trying to focus on a pretty small area.

Thanks,
Ed

 

[Ed*L]

Here's a pic of the bar, You can see the pitting is pretty constant the whole length.

Ed

View attachment 38244

 

[bump_r]

Do my eyes deceive me in that the patches of surface irregularities match up with what appear to be waaaaay-too-hot assembly welds? Looks like the factory cooked the bar during build, weakend the rail material, and you're hosed. But that's just me looking at a picture. Do the bar rails roller-coaster in profile, further indcating messed-up steel? Are the rails wearing internally at the sites (hour-glassing, groove wider in some spots, but narrowing back down in others)? May be too fresh of a bar for too many symptoms to show. Good catch on the situation.

 

[ShoerFast]

Just .02 cents worth, as not seeing the bar in person it may look worst then it dose by the picture?

It looks to me that the bar may be a little hard at the rails, and will heat-treat themselves in time with some hard work? If I may explain, ever notice how some bars will get blue-hot on saw that don't oil well? That blue-hot heat is in effect treating that bar, it's too hot for most metals good, but it's extreme I hope shows my idea for here. (to the left is just a cut and enlarged section of the bar rails)

Just as new bars seem to seat in with ware, if you catch them just right in the sun-light, you can see a nice straw-yellow color on the bar-rail - chain surface, it is after that that we see the like glass smoothness come out, I really like bars that hit that sweet spot!

I would mention it to your dealer, if you wanted to, lightly run a hone over it, like an Arkansas med. or hard, and run it, if it gets worst, exchange it, but if it trues up, you may have something that will wear for a very long time and run very smoothly?

 

[bump_r]

I'm just not buying the "heat treat as you use it" theory. At all. While the bar obviously sees temperatures above ambient during use, I just don't see one attaining straw or blue coloration in normal use. That's friggin; HOT - you'd see the bar oil smoking, coking up, and generally uuuug- uh-lee operation. Definitely NOT something that would be planned, expected, or anticipated by a manufacturer. Add to that the shere uncontrollability of such a critical manufacturing process. Let the consumer blindly heat-treat steel? Sorry, but I can't get in on this one. Bars must come finished, ready-to use.

 

[Lakeside53]

The laminated bars are welded together (you can see the join welds), then induction hardened about 1/2 inch from the edges all around. If you strip off the paint, you can see the "blue/yellow band". I doubt there is anything wrong with the bare.

 

[bump_r]

The laminated bars are welded together (you can see the join welds), then induction hardened about 1/2 inch from the edges all around. If you strip off the paint, you can see the "blue/yellow band". I doubt there is anything wrong with the bare.

Is that rail edge surface normal? Sure is awfully rough for lazer-cut steel...

I see the brown/straw spots as well as the much larger blue ones. The rail surface appears to be different adjacent to these blue spots as compared to between them. Or is the blue surface just giving the illusion of rougher surface?

 

[ShoerFast]

I'm just not buying the "heat treat as you use it" theory. At all. While the bar obviously sees temperatures above ambient during use, I just don't see one attaining straw or blue coloration in normal use. That's friggin; HOT - you'd see the bar oil smoking, coking up, and generally uuuug- uh-lee operation. Definitely NOT something that would be planned, expected, or anticipated by a manufacturer. Add to that the shere uncontrollability of such a critical manufacturing process. Let the consumer blindly heat-treat steel? Sorry, but I can't get in on this one. Bars must come finished, ready-to use.

Bunp_r

As I offer this as .02 cents worth, I did say that bars that were ran blue is way too hot, (like the normal Wildthingy) but had offered,

"Just as new bars seem to seat in with ware, if you catch them just right in the sun-light, you can see a nice straw-yellow color on the bar-rail - chain surface, it is after that that we see the like glass smoothness come out, I really like bars that hit that sweet spot!"

As it's not that "friggn" hot, that is in the 400 deg. range, and very easy for metal - metal contact to hit that temp. Just as the cutters hitting wood reaches 212 deg as we see steem offten. If you have ever smelled hot bar oil, your into the 400 deg range. High-speed steels seems to not even work unless there smoking the oil a little, look at drill-bit cutting iron.

From what I hear, as I have not ran one yet, that GB bars count on the chain temp - ware Harding to seat the rails, as GB Titanium bars will look like a dog-turd till they seat, but will then last a very long time.

 

[Lakeside53]

Is that rail edge surface normal? Sure is awfully rough for lazer-cut steel...

I see the brown/straw spots as well as the much larger blue ones. The rail surface appears to be different adjacent to these blue spots as compared to between them. Or is the blue surface just giving the illusion of rougher surface?

Not sure... When I put a bar though out bar grinder, it's rougher than that. A short time in the wood, and it's polished up but you can still see the grinder marks for some time.

 

[bump_r]

I have no doubt that some wear-in will occur - it's the in-use heat treament theory I don't buy. Where's the quenching? If brought up to a significant temp and allowed to cool naturally, whould that not soften the material? or is that your position - the bar was intentionally shipped extra-hard with the intent that it will soften (agreed, also a heat treatment) with use? I ain't buying that, either. Not to argue, but it jsut doesn't jive. Maybe I read too much into your post.

It looks to me that the bar may be a little hard at the rails, and will heat-treat themselves in time with some hard work? If I may explain, ever notice how some bars will get blue-hot on saw that don't oil well? That blue-hot heat is in effect treating that bar, it's too hot for most metals good, but it's extreme I hope shows my idea for here. (to the left is just a cut and enlarged section of the bar rails)

 

[bwalker]

I'm just not buying the "heat treat as you use it" theory. At all. While the bar obviously sees temperatures above ambient during use, I just don't see one attaining straw or blue coloration in normal use. That's friggin; HOT - you'd see the bar oil smoking, coking up, and generally uuuug- uh-lee operation. Definitely NOT something that would be planned, expected, or anticipated by a manufacturer. Add to that the shere uncontrollability of such a critical manufacturing process. Let the consumer blindly heat-treat steel? Sorry, but I can't get in on this one. Bars must come finished, ready-to use.

Its called work hardening.

 

[bump_r]

Work hardening involves the material being displaced, not just loaded or heated. Try again.

 

[Dennis Cahoon]

I know Cannon experimented with air harded steel in a batch of hotsaw bars. The tolerances were too tight to run .063 gauge without the top and bottom rails turning red hot and shrinking againists the chain by the 3rd cut.....so most ran .058 to avoid the shrinkage....so...some metal used may be air hardened.

I've also used air hardened and oil hardened rod to hard surface bar rails. The oil hardened rod works best. Just add to the area you're trying to harden, shape it the way you want, reheat it and quench it in oil and it's hard surfaced just like using stelight. The air hardened rod hardened as soon as it cooled and is harder to work with.

Also, when you resurface your bar rails on a Bar Shop the small grooves hold oil and give you better lubrication and less heat.

 

[ShoerFast]

I have no doubt that some wear-in will occur - it's the in-use heat treament theory I don't buy. Where's the quenching? If brought up to a significant temp and allowed to cool naturally, whould that not soften the material? or is that your position - the bar was intentionally shipped extra-hard with the intent that it will soften (agreed, also a heat treatment) with use? I ain't buying that, either. Not to argue, but it jsut doesn't jive. Maybe I read too much into your post.

It's all good!

As I may have come across as too defensive, this is a huge hobby of mine.

Heat treated metals all seem to fall between making huge burrs, to one that chips or flakes easily, this bar seems the latter?

When I experiment, and just for the sake of this post, lets call the metal 5160 steel.

5160 or most carbon steels can be work hardened or harded if brought to critical temp, or when a magnet wont stick, and quenched rapidly. But that is too hard for most any application. to draw the temper out of that, the real heat treat needs to be baked out , or made a softer, I do that for my experimenting in a regular oven or a fry-daddy with a candy thermometer, oil just smoking a little is right at about 425deg. and leave a slight straw color.

http://www.anvilfire.com/FAQs/temper_colors.htm

It would be clear that saw-bars need to have some temper so they spring back straight, but not to hard that they brake when twisted, that would leave the rails a little soft, so I'm sure they case-harden the rails, a tricky processes IMO, even with hundreds a day the actual treat could vary, or vary from spot to spot on the bar, and that is what this bar seems like it is doing?

My bet, just running this bar will bring it around, and it maybe be a little better then one that was too soft to begin with?

 

[ShoerFast]

Its called work hardening.

Yes
And there is "age-harding" ware just the temp flucations work harden some steels.

 

[ShoerFast]

I know Cannon experimented with air harded steel in a batch of hotsaw bars. The tolerances were too tight to run .063 gauge without the top and bottom rails turning red hot and shrinking againists the chain by the 3rd cut.....so most ran .058 to avoid the shrinkage....so...some metal used may be air hardened.

I've also used air hardened and oil hardened rod to hard surface bar rails. The oil hardened rod works best. Just add to the area you're trying to harden, shape it the way you want, reheat it and quench it in oil and it's hard surfaced just like using stelight. The air hardened rod hardened as soon as it cooled and is harder to work with.

Also, when you resurface your bar rails on a Bar Shop the small grooves hold oil and give you better lubrication and less heat.

Dennis

Are you useing an air-harning hard surfacing rod? As having the number, as that is something I would like to try on horseshoes, cause it's tricky if I quinch them sometimes they worp and wont fit, or reshape cold.