Chattering band-Kasco

[Deere80]

what would make the cut look like this?  2 weeks ago I installed Cooks roller guides and now I am getting rough cuts, I am using .045 7 degree Kasco bands that are new out of the box and have tried more than one so that isn't the problem.  If I speed up it will not give me the gouge marks but I am pushing it so hard that when I hit a knot it gives me a wave with a brand new band and if the board is wide I cant push hard because I do not have the horsepower to go fast.  Do I not have enough down pressure on the rollers??  I have them set at 1/4" down pressure.


 


 


 


 


 

[Kbeitz]

I'm kinda new at this but I would like to make a guess that you have
one or two teeth out of set.

[ladylake]

I'd try tightening or loosening the tension, is your blade level with the deck before adding down pressure.  Steve

[Mt406]

I get the same pattern.
My mill is a LT 35  25 hp
It seams to happen to me on wide cuts over 8 in.
I am thinking (for all that's worth) it has to do with blade tension and speed.
most of my wood is for ranch's they don't care much about looks they want cheap.
when its finish wood I go with a 4 it gives me a smooth cut and cuts knots best for me   

Scott

[pineywoods]

Most common cause for that washboard pattern is a slipping drive belt. Band wheel belt worn down to where the blade rides on the metal of the bandwheel will also cause that. The blade gets a good bite into the wood and slows down or even temporarily stops, then pulls loose from the wood and resumes speed..

[Deere80]

I have a new drive belt installed ten hours ago that i checked last night and is tight.  If that is the case Pineywoods why would it be a lot worse when I go slow and when I increase my feed speed it is a lot better.  Wouldn't it slip more if i am pushing the blade harder into the material?

[Mt406]

Piney
That is a good thought My mill has only 100 hrs and I adjusted the drive belt when it was recommended I will check it.
On my mill it only seams to happen with 7s.
If I am remembering right I think the WM dealer said I didn't have the HP to run 7s or was he talking about the turbo 7.

[Cutting Edge]

what would make the cut look like this?   If I speed up it will not give me the gouge marks but I am pushing it so hard that when I hit a knot it gives me a wave with a brand new band and if the board is wide I cant push hard because I do not have the horsepower to go fast. 

This is a common problem with smaller mills trying to run to aggressive of a hook angle.  The engine does not have a sufficient torque curve to keep the blade at a consistent speed and blade speed drops, harmonics set in/take over... IMO

Most small mills are already running on the low side of the blade speed to compensate for the lack of engine HP and a VERY narrow torque band in relationship to RPM's.  Combine that with sawdust spilling past the gullet due to a small particle size and inconsistent feed rates, the problem begins to compound itself.  Hence, poor cut quality.

As ladylake suggested... Make sure tension is proper.  Adding down pressure may help but it will only cover up the root cause IMO.  There are many mills of this class running 3/16"-1/4" down pressure making excellent lumber provided the best suited blade is being used.

If tension is right, a small reduction in the amount of set may prove to be the best solution to help stabilize the blade in the cut.  If you have the ability, resharpening at a 4 deg hook angle will probably produce the biggest improvement.

I didn't have the HP to run 7s ....

In my experience and feedback from customers, this is a prime example of why a 4 deg blade works best on these type mills and why I always recommend it to most customers under 25hp.


Hope this helps.

[Deere80]

So if that is the case Cutting Edge why did I not see this ever with a 10 degree band then? 

[Cutting Edge]

The 7 deg. blade has a taller tooth/deeper gullet, which in turn, takes away from the beam strength of the blade.  And at lower speeds (surface ft per minute), makes it more susceptible to harmonics. 

Maybe the best way to put it in different terms would be how a vehicle acts when a tire is out of balance and at certain speeds it will make the vehicle shake and if that speed is maintained it will get progressively worse (sometimes violently).  Increase speed and the feeling of the vibration goes away.  Similar to how you described increasing feed rate and the chatter marks went away... but lacked the power needed to maintain a smoother cut.

Vibration causes harmonics.  This could be from the engine, the belts, band wheel out of balance, flat spot on guide roller, etc.  or a combination.  Regardless, this can/does get transferred to the blade.  The blade is flexible and has little chance of resisting these forces.

If you compare the 10 deg profile to the 7 degree, the difference is very noticeable.  The Kasco 10 deg and 4 deg have the same tooth height/gullet depth and back angle, only difference is the hook angle.

[Ox]

Harmonics.  When I see this I change the tension in the blade and it goes away.
Not saying the others are wrong, cause what they're saying is right too.  This is simply what I do. 

[york]

Grab a hold of your band guide`s and see if they are not moving-they need to be rigid,try without band tension...

[Deere80]

York,  you saying the roller guides?  to see if I have a bad bearing or loose bolt not holding it steady?

[york]

Yes,they need to be rock solid,no movement,no vibration...

[Deere80]

Well last night I went and tightened my drive belt, checked the rollers to make sure they were solid, and adjusted one of them a little because it was off  on the level of the blade.  Cut a log and it was better but still get the chatter marks a little so will just have to play with it some more to try and fix it.

[slider]

Deere80 i am with Cutting Edge on this one.I saw a lot of knotty pine.I don't get the chatter you are getting with my lt 70 but i did with my old lt 40.I did however change to the 4 degree bands and i don't get near as much wave as before.The lt 40 was 24 hp and the lt 70 is 62 hp.Hope this helps.

[gmmills]

   You do not have enough horsepower on your mill to run a 7 deg blade. You can adjust you mill until you are utterly frustrated and will not correct the problem.  Cannot emphasize this enough, any mill with under 25 HP should be running a 4 deg blade as an all around blade. Low hp mills are not capable of maintaining optimum blade speed, narrow torque band, to be able use a blade of higher hook angle. Being able to maintain blade speed is paramount to sawing accurately while achieving peak productivity for your mills hp rating. Get yourself some 4 deg blades. 

[YellowHammer]

Harmonics and at least one tooth out of set.  The harmonics is simply a blade that vibrates excessively and gouges wood.  Caused by what everybody has said.  It's easy to detect, look at the band when it spinning, you'll see vibration before it ever hits the log.

[Kbeitz]

I cut ash in the fall last year with 7 deg. blades with a 13 hp Honda.
I just bought a box of 4 deg. blades and have not tried them yet so
I don't know how much difference that I'm going to see. But I don't
think I had any problem with the 7's like everyone said I would with
only 13 hp. I will report on how much difference that I find.

[fishfighter]

   You do not have enough horsepower on your mill to run a 7 deg blade. You can adjust you mill until you are utterly frustrated and will not correct the problem.  Cannot emphasize this enough, any mill with under 25 HP should be running a 4 deg blade as an all around blade. Low hp mills are not capable of maintaining optimum blade speed, narrow torque band, to be able use a blade of higher hook angle. Being able to maintain blade speed is paramount to sawing accurately while achieving peak productivity for your mills hp rating. Get yourself some 4 deg blades.

I have to disagree with this. I have the same mill the OP has. I use 7drg Kasco blades and I don't have the problem he is having. I find those 7 drg blades are three times better then 10 drg. ;D

OP, did you have this problem before changing out your guides?

OP, check your throttle linkage to make sure your engine is running at full speed. Mine had slipped in the past.

This is some oak fresh felled and I sawed this morning using Kasco 7 blades. No marks.



 

[Cutting Edge]

Another point worth mentioning...

Judging by one of the pictures and the fact of being located in N. Dakota, there is a good chance Deere80 is sawing partially frozen logs.

As some of us know, frozen logs are a whole different animal.  Partially frozen (thawed outer/frozen inner or vice versa) are even worse.

[barbender]

Good point, Cutting Edge. I also agree with your assessment of the cause of the striations, the only time I get those marks is when I am moving too slow.

[4x4American]

Although I don't think there's anything wrong with the blade (might not be the best profile for you), ffr, don't rule a blade out because you tried a few new ones.  It's not a bad idea to pull a blade off early that's cutting good and save it as a benchmark blade.  Before you pull it off, spritz it with a blast of your diesel/bar oil to keep it from rusting over time.  Get you some 4 degree blades and don't look back.

[Deere80]

Well with the help from you guys giving suggestions and talking on the phone with Cutting Edge I got it figured out why I was getting the washboard look on the wood.  I readjusted the Cooks rollers that didn't change anything, I added more tension that didn't do anything, I added even more tension that didn't help, loosened it up under what is recommended that didn't do it.  Then  both Cutting Edge and Goose63 mentioned to me if I had changed out the rubber bushing under a steel washer where you tighten the blade up with the T-handle. I never knew it was even there and Goose has the same mill which Woodland sent him some dished/spring washers that replace the rubber.  Called Woodland up they sent them free of charge installed them put on a 4 degree Kasco blade and bye bye to the washboard look.  I bought a box of 7 degree from Cutting Edge which he told me to buy 4 degree because that would fit my HP of my saw better but I didn't listen to him which I should have because he was right the 4 degree cut much better than the 7s for my saw.  So I just sharpened my 7s to 4s and they work great.  If you need any blades I would recommend buying them from Cutting Edge he was a big help for me trying to figure this out and he is very knowledgeable all around.


 
This is the rubber bushing.


 


 


 
Cuts after fixing the problem


 
Slab from same  log before fixing the rubber washer.

[ladylake]

   From Cutting edge  (The 7 deg. blade has a taller tooth/deeper gullet, which in turn, takes away from the beam strength of the blade.) There is a lot of truth in that statement, I find blades with a shallower gullet cut straighter, even adjusted my sharpener to make a shallower gullet.  I tried some Kasco blades with a deeper gullet than my Simonds and they didn't  cut very good at first but after a few sharpening's when the gullet matched my Simonds blades they cut way better. More beam and less tooth height trying to twist on the blade.  A mill south of me had exactly the same results.   Steve