This is the worst sawing I have ever done

[kelLOGg]

and, it is ERC!


 

 


Someone brought me a load of old cedar logs with the sapwood completely rotten, some very knotty and others clear to few knots. Those with few knots sawed beautifully but the knotty ones were worse than hickory. In one of the logs the knots traversed the entire 12" board width in places and as the band encountered these knots smoke emerged and the cut dived changing the cut from 1.5" thick to more that 2.5". I continued the cut so I wouldn't have to contend with trying to get the band out.  The band was newly sharpened and set and had made only 2 cuts in the log before encountering the knots. It is a WM 1.25" 4° with 0.020" set. I pulled the band to re-sharpen and did not see any damage to the band - just set that was reduced to about 0.015 to 0.018. I was shocked the 4° couldn't handle this situation. I made the next cut sawing very slowly with not much improvement. In the past I have said of sawing cedar that a dull butter knife will cut it but I have been taken down a few notches now. Anyone else seen this in ERC? I have sawn thousands of board feet of ERC but this one knocked my socks off. 


 

 

[Old Greenhorn]

Well I have seen that with blade problems, but never on cedar. Holy cow batman, that is some wave! That was quite the learning experience I am sure.
 I bought some white pine from a mill on my road a few years back before I have my mill and there were two boards with the exact same wave (I didn't pick them, he did and delivered). I looked at the boards and then at the sawyer and said "How.....?" he just started cussin' about bad blades, bad day, not enough time, and other stuff. I just laughed. I cut out sections and mated the waves together (face to face) to make the rail stiles I needed. It looked pretty cool.
 When you get lemons..... :D
 OTOH, if he needs them flat, I hope he has a good planer. ;D

[kelLOGg]

OTOH, if he needs them flat, I hope he has a good planer. ;D

I will plane before anyone sees it ;D  Everyone on the FF is worn to secrecy, right? :D

[thecfarm]

The days before I knew about the FF I sawed some spruce with 10° blades.    Good thing I had a brush pile close by. ;D  I got rid of those quick. Kinda like a bad bondo job.  :D

[moodnacreek]

This is a little hard to explain. There is a cedar lot where I have been cutting e.r.c. for a few years. When I first started you could not drop a tree because they where so close and the oldest [75 yrs.] where triples. Some of the side branches that grew up from the bottom had been dead for a long time and they where petrified. I mean hard like dead locust, sparks off the chain saw hard. I sawed over 10,000 board foot of lumber from this spot and am going back for more now. It was only those old, squatty fat branched that had the hard knots. This has to be what you got.

[shelby78]

Did you or could you try more band set? I could be wrong but I thought more set helped with tricky wood?

[kelLOGg]

Some of the side branches that grew up from the bottom had been dead for a long time and they where petrified. 

I like the word "petrified". If something similar to that really happens it would match my observations. Whatever the case, I glad someone else has observed hard ERC.
Is there a hardness scale for wood? If so, how do you measure it?

[kelLOGg]

Did you or could you try more band set? I could be wrong but I thought more set helped with tricky wood?

I would think minimal set would help stabilize the band body but not so minimal to increase friction. Just guessing.

[kelLOGg]

I cut the next ERC with the same blade with no setting or sharpening prior to the cut and the results were excellent. There is something weird (hard) about those knots :P



 

[pineywoods]

Truth of the matter, some trees just refuse to lie down and be made into lumber. They fight back in every possible way. Had a nice white oak do me that way last week. Thick n thin wavy 2X6 for livestock trailer floor. I refused payment for the job, but customer insisted on replacing the 2 blades I broke. Said "them cows don't know anything about lumber.. ;D Questioned the source of the log. Turns out the tree had a 25 degree lean and 3 big limbs all on the downhill side.  STRESS

[caveman]

Kellog,
Look at Janka scale for wood hardness.  I think ERC has a Janka scale rating of 580, which is relatively low.  The knots can be much harder.  If sawing along in soft wood and suddenly hitting harder wood without slowing down or if everything is not just right deflection may result. Janka scale rating involves how much force (in Lbs.) it takes to press a ball bearing of a certain size (1/4" maybe) half of the diameter of the bearing into the wood.  Did your blade happen to get a lot of pitch on it while sawing the wavy cut?  A blade with pitch will heat up and lose tension and may result in a wavy cut.  We experienced this last week on a wide cut in live oak.

We had a heck of a time cutting heart pine flat and finally settled on Kasco, 1 1/2", 7°, .050 bands.  They have done much better than the 7°, 1 1/4" turbo WM, .045 on the heart pine but still we get a wave every once in a while.  

The other stuff has to be right:  (YellowHammer has done a good job explaining this phenomenon).
Blade, check with bgat
Enough deflection with the blade guide rollers (1/4")
Sharp blade
Proper set
Proper tension on the drive belt

 

[Ljohnsaw]

No one mentioned cutting direction.  Were you cutting from the top down or bottom up?  I would expect top down to cause a dive as the blade is forced to follow the grain of the hard knot.  And in your case, a whole line of knots.

[kelLOGg]

Caveman: there was no buildup on the blade. I rarely get that from cedar.

ljohnsaw: I was sawing from bottom of log to top. That was the way it was oriented on my rollway and its too difficult to flip it around.

[doc henderson]

Must have been something with that tree if you could cut fine in another log with the same blade.

[Florida boy]

I wonder if super high silica content is to blame?