Blade Breakage……a head scratcher???

[POSTON WIDEHEAD]

Your thoughts.
I've been sawing ERC lately.
Lots of it.
I never use a brand new blade on ERC but use a new re-sharp blade when starting my day.
I rarely use the debarked on ERC because of knots, dips, flutes, etc. but debark on good slick logs 8" and up.

Recently, I stopped using lube on my blade because I did not see a build up of pitch....really none at all.
I can saw about 300-350 bf and POW....I break a blade. I have done this several times.
When I saw ERC....I walk the dog and spit the boards out. There are no waves in my boards when the blade breaks.
I go back to using lube again.....and the blade will run until I see a need to change it......starting to dull.

Is it possible for blades to break because of "not using lube" even though there is no visual need for lube?
My alignment on the mill is very good and I have good belts. Rollers roll perfect and space on each side of the blade going through the blade guides are within specs. When sawing ERC....I put around 2500 psi on my blade....about 2800-3000 on Pine.

This problem DOES NOT happen on other species where I use lube. Perfect boards.

[ladylake]

ERC spits out a lot of derbis on the exit side, does your mill have a good chip deflector to keep the debris from getting between the guide and drive wheel.   My theory is that debris is hard on the band if it gets between the band and wheel.  Steve

[POSTON WIDEHEAD]

ERC spits out a lot of derbis on the exit side, does your mill have a good chip deflector to keep the debris from getting between the guide and drive wheel.   My theory is that debris is hard on the band if it gets between the band and wheel.  Steve

Steve....if I have a deflector......its what ever came on my 2010- LT40. You have made a good point I have never thought about....maybe when I use lube, it keeps it washed out......I don't know.
Thanks Steve.

[hamish]

Perhaps a heat issue in the band when not using lube.  Even thought it well below freezing here (my -40C washer fluid froze on the weekend, kinda hard trying to mill and pee on the band at the same time).  At time lube is still required.  Usually the harmonics in the band tell me when a shot of lube is needed.

[drobertson]

you asked for my thoughts, so here it goes, you said you never ran a new blade on erc?  Not sure why, but if it works use it, re sharps break do to fatigue most of the time, not knowing the cycle time you have I can only guess that this is part of the equation. the other as mentioned buy Steve, flying debris caught between wheel and band.  which with a fatigued band will go. I can't remember when I've broke on in a ECR log, but now that I've said it will expect it, thanks, if the tension is good while dry or with lube I see no heat issue, but then again not there, so can't say.  I'm of the mind set of Murphys' law?  Does it happen every time you saw ERC?   I don't keep records, only mental notes so I'm not saying nothing, except blades break, and it's just metal fatigue, no cause of your operating procedures.  I once had 5 of 12 break brand new with no real answers,  I think it's in the heat treatment/manufacturing process.    At least you don't live in Ukraine !   or anywhere else I suppose,    david

[xlogger]

I hardly ever break a blade unless I'm sawing ERC. I broke two blades yesterday sawing cedar. One had be sharpen 7 times and the other only twice. I put a chip deflector on my mill like Steve suggested, it seem to help somewhat but I think those small pieces of bark still get by it. I put a post here about it awhile back and seem to be the only one with the problem. Ricky

[red oaks lumber]

even in the great white north i have cut erc :D my limited experiance says the wood is a gritty dry, which to me makes the blade build heat if not using lube.

[POSTON WIDEHEAD]

David, the reason I never use a brand new blade on ERC is because the "Jack Legs" (old saying) that bring these logs to me, get them mostly out of yards and fence line. Their logs are almost always under 8 inches. I'd rather hit metal with a blade that has been resharpened 7 or 8 times than a new blade.
I always ask where the logs come from.

Sometimes I get ERC 8 inches and over that have come from a mixed plantation.......big logs, no metal, but I still use a good resharp blade.

But back to the breakage problem......I think it may be a heat issue also, Red Oak and Hamish.

[drobertson]

Hear ya on the jack legs and deer pegs! ;D   I was just trying to say on any job I saw I (most always) start with a new blade.  Re sharps, depending on how many times it has been factors in.  I just think if the heat was there the tension gage would have shown it, that's all.  I will stand on fatigue, and debris.  Fatigue especially if it happens before entering the cut, which has happened to me as much or more than while sawing,   
david

[xlogger]

Both of my blades that broke yesterday where out of the log.

[Ga Mtn Man]

Keep an eye on your drive wheel bearings.

[Planman1954]

I would use the lube no matter what I'm sawing...

[POSTON WIDEHEAD]

Keep an eye on your drive wheel bearings.

She's tight. This problem only happens with ERC when I'm not using lube......but I can change that.  ;D
Thanks Planman.

[drobertson]

For the record, I most always use blade lube, times I don't, is from being so close to finishing a cant and to lazy and in too big a hurry to just get done with the cant.  Still, my gage shows the most smallest of blade expansion, which is caused by heat.  I watch the gage as close as I do the blade guide, and back stops and clamp. 

[scully]

If it was a heat issue ,you would see it on your tension gauge , while makeing the cut tension would fall off . Also I have had trouble with the .055 bands snapping {when new }  Bands with a ton of spin time I think would not hold up well in tough cutting ,just my opinion but after 3to4 sharpenings I would think the metal is starting to lose tensill strenth .

[POSTON WIDEHEAD]

Scully, I use the .045 and I have seen the psi fall while sawing ERC without lube.

[Rockn H]

I was going to ask if you had to adjust the tension on the blades much while sawing without lube.  Sounds like the blade could be heating up more.  I never saw anything without lube.  Guess it's an old habbit from when Daddy had a circle mill, had to keep the blade cool.  ERC reminds me of sawing sand paper..... you can see the sparks flying out of the log when it starts getting dark.  lol

[GeneWengert-WoodDoc]

Technical explanation:  Eastern red cedar when it is freshly sawn has a green moisture of 33% MC.  Many other species have 75% MC.  Southern pine is often 100% or higher.  So, the sawdust chip with ERC is lighter weight (less water and a low density species) so it is harder to get it out of the gullet and away from the saw, plus it has less "natural" lube (less water) in the wood than many other species.  ERC is quite dry.  Adding lube (water or other) makes the chip heavier so the chip can be carried away better and the lube also reduces heating and binding.  Hopefully, this makes sense.

For the green MC of various wood species, see table 1-5 at
fpl.fs.fed.us/documnts/usda/ah188/chapter01.pdf

[ladylake]

 The last time I started breaking too many blades was when my chip deflector got wore off and was too far above the blade.  Steve

[pineywoods]

I have a slightly different take on broken blades. I don't think a perfectly sound blade suddenly breaks. Been scratchin my noggin and figgerin for years trying to figure out why blades break. I know about metal fatigue and how many trips around the bandwheel. That doesn't explain why some break right out of the box and others last 10 or 8 sharpenings. I started looking closely at the ends of the broken blades. In almost every case, close inspection will show a crack about half way across the blade, all dirty and rusty, obviously been there for a while before the other half finally gives up. In other words the blade broke because of previous damage, maybe weeks ago. There may be a connection to lack of lube, but I don't see heat being the cause. Most likely it's crud built on the top of the blade. That stuff is sticky, otherwise it wouldn't stick to the blade. A twig or piece of bark will stick to that crud and be carried around the drive wheel. Demo this. Shut the mill down, leave the blade fully tensioned, and stick a match stick on top of the blade just before the drive wheel. Rotate the wheel about 90 degrees by hand. Observe the blade where it lays on top of the match stick. There will be a much sharper than normal bend in the blade, especially if the belt is worn down to where the matchstick rides on the metal sides of the pulley. Most of us know from experience that worn down belts seem to cause increased blade breakage. On woodmizer guide rollers, there is a small round metal bar that sticks out over the blade just before the inboard roller. It's there to knock stuff off the top of the blade. My observation is that on most mills, that bar is either missing or bent. ????
That's my theory, comments ??? Keep yer blades clean  8)

[Peter Drouin]

If the blade gets hot, it's dull. With or with out lube ;D

[Magicman]

I agree 100% with Peter above.

I realize that some disagree and with good arguments concerning water swelling the sawdust and causing more heat, but personally I use the same amount of lube with everything that I saw, and that includes ERC.

I have never experienced additional or increased breakage with ERC, but I do have increased dulling.  When the tension drops off, I feel the blade.  If it is warm, it gets replaced.

[Ga Mtn Man]

Keep an eye on your drive wheel bearings.

She's tight. This problem only happens with ERC when I'm not using lube......but I can change that.  ;D
Thanks Planman.

I was actually talking to xlogger.  Sorry for the confusion.

[Tom the Sawyer]

Your blade breakage may be a combination of factors, not lethal by themselves but, combined with a lack of lube, could be causing your problems. 

Heat can be generated by friction of the blade passing through the kerf and by the blade flexing.  Not only does it flex twice every for every time through the log but if you are pushing them pretty hard you may also be flexing the back of the blade during the cuts and when you enter the log.  Is it running against the rear flange of the guide rollers when you are pushing it?  You might consider using an infrared thermometer to check the blade temperature when using lube vs. when running dry. 

Good luck tracking it down.

[drobertson]

I am going to just say it.  Nothing is "perfect in sawing" and surely not in steel manufacturing, in regards to band blades at 20 bucks a pop, give or take.  Carbon content, and the rest of the elements that are incorporated with the alloying composition have so many factors as related to the heat treatment processes, and manufacturing, that when all the varying conditions that sawmilling impose, stress, wear, and impact, not to mention the tension, I just wonder why anyone would even wonder. Yes it is frustrating when a blade breaks, many times at the worst time. But really, the bands that are sold, bought, and used by all of us are pretty good for the money. Real good.
If it takes more coolant, than it should be used, without question, if the justification exist.  I say whatever it takes to maximize the tool life then do it.  In the end, all cutting tools will fail at some point, and all measure should be made to maximize the tools life.   sorry, just a rant. seen lots of tool life loss in many areas,   david