Saw wobble. Need some expertise.

[francismilker]

Here's the scenario.  I'm sawing Hickory.  I'm using the standard 10 degree blades.  WM LT-10 with 10hp gas motor.

Today after finishing up sawing some ERC logs I had staged it was time for a band change.  I put a new band on and started slicing away.  After I got the first small log squared up and started slicing 1x6's I noticed my carriage wobbling like I've never noticed before.  It was acting as if I was putting too much push pressure on the sawhead so I backed off a little.  The wobbling would slow down and eventually go away.  When it went away I'd speed up a bit and the wobble would come back. 

Problem is, even though the band was chewing the log up real nice and cutting like a new band should I was only able to move at a snail's pace through the log.  (like it was taking me several minutes to get through a 14' cut on a 6" cant. 

The wobble didn't happen on ever cut at the same place in the log.  Sometimes it didn't happen at all.  I tried making some adjustments to the water flow and tried experimenting with different sides of the cant to make sure it wasn't due to some kind of stress in the log. 

Should I try a different degree band?  Should I try different lube other than water?  There was no sap at all.  I made a few cuts without lube and it cut OK.  I just don't want to shorten the life of my band. 

I ended up cutting 10-1x6x14's, 6-2x6x14's and 6-1x6x8's before I started experiencing dull band issues with some ups and downs to my cut.  I made sure the log was very clean before starting.  Any advice would be appreciated.  I like the grain on Hickory and would like to cut another 10 miles of it.  I just don't think I'm doing something right or I wouldn't have been experiencing the carriage wobble and shorth band life. 

Thanks.

[YellowHammer]

I have never used a LT10 but I would definitely say you are using the wrong band for hickory and the head wobble along and a slow feed could easily be the result.  For hickory, I use a 7 degree or even a 4 degree for the big logs.  I would think the 10 degree is way too much for hickory, and wouldn't cut well, or for very long, which is what you are seeing.  Also with hickory, I really like to double or even triple dose up on blade lube additive into the water, or just switch to oil based agricultural lubricants entirely.  In my experience, hickory ranks near the top of being extremely hard on both bands and sawmill, and requires things to be dialed in just right. 
YH

[customsawyer]

This is why we say that hickory is the  . Any time I start having trouble sawing a log the first thing I do is change the blade, before I make any adjustments to the mill. Even if the blade is new it still might have a issue. Was the blade leaving any lines on the boards? 

[dgdrls]

Francismilker,

Same experience with my 10, I didn't get 7 or 4 deg bands prior to selling
mine but I know they are available from WM.
I did run some 9 deg bands with more success in hard wood

spec an 045 thickness band not 042

http://www.woodmizer.com/us/Blades/BuyBlades.aspx

DGDrls

[T Welsh]

I always have problems with Hickory. I always start with a new blade, and when I start having problems I change it and they go away! Sometimes I might get a log a blade other times it will last longer. The stuff is just hard. Tim

[rimshot]

My lt10 is brand new and I am a new user so what do I know.  I have never sawed hickory either.  yesterday I cut my first log.  My lt 10 cut fine but did act like  yours a couple of times as it got a little side to side shake toward the end.  I called WM and they had me do two things TIGHTEN the blade and they meant tight.  The tech said I want to see you so it takes two hands to move the band tightening shifter lever and tight enough so if it slips out of your hands and smacks you in the face it would knock you out.  I was glad that did not happen.

He also pointed out with a new belt it was going to stretch.  I opened the door and inspected and was I surprised how much that belt had stretched.  So  that remains the first thing on my list this morning is get that linkage under the engine lengthened to tighten drive belt.

rimshot

[5quarter]

Yellowhammer beat me to it. You will have a much better result with less hook angle when you're cutting hickory. If the wobble you mention is moving the sawhead from side to side, it is likely due to the aggressive hook angle of the tooth. Bigger mills generally don't see this as the weight of the sawhead is great enough to counteract the lateral force of the blade. I use 8° blades on most everything, except dried Hedgeapple, Hickory and Buroak. I have a couple bands that I've resharpened to 4-5° just for them.  ;)

[bigtim]

My LT10 is about 6 years old,on the right mast (square one).There is a litte black pad 

[bigtim]

ITS ME; cant see or type. Anway adjust that litttle pad to .015 to.020 thou clerance and it should help.   Tim

[beenthere]

bigtim
Welcome to the Forestry Forum.
Any of your posts can be edited by going to your post and clicking on "Modify" button for correcting the "It's ME" errors.  ;D

[Magicman]

bigtim, you have been mighty quite for two years.  How about an intro and sharing a bit about yourself and your sawing experiences.

[francismilker]

Thanks for the reassurance and thoughts on cutting hickory.  I sure like the looks of it but it's HARD as all have said.  I think I'll call WM when I get another few days off and have time to tinker with trying some different bands.

[drobertson]

FM, it very well could be a blade geometry issue, the first thought that came to mine was maybe a loose or worn bearing on the carriage. Just allowing a little more play when in a tougher wood,   hope all goes well,  david

[YellowHammer]

WM will be able to set you up with the right band configuration.  Just tell them you are sawing something that is as hard as, well, as hard as dried hickory... :D  Then use the time to investigate any mechanical issues or adjustments, tighten up any slack, etc.  When the new blade gets in remember to pour the lube to it, because if a blade gets hot sawing hickory, it's dead.  Make sure there is no pitch buildup on the blade, I usually visually check the first pass or two until I get the lube set correctly, and I feel the blade to make sure it's not getting hot, or even very warm.
Let us know how it turns out and good luck.
YH 

[francismilker]

I plan on calling WM first thing Monday morning to get some assistance with a new degree of band.  I've been pouring enough straight water lube to it that a slurry of sawdust is standing on the freshly cut board.  Would you all recommend another lube other than straight water?  I don't see any pitch buildup on the blade at all.

[dgdrls]

FM,

you can add a bit of Pine-sol, makes it more slippery,

Sawdust on the boards is a tooth set issue, too much or too little,

Look to Suffolk Machine for some tips http://www.suffolkmachinery.com/six-rules-of-sawing.html

When you talk to WM they may very well tell you (as they did me) LT 10 bands are 9 or 10 Deg only.

that is why I posted earlier you have to ask for a thicker band, they make them, they just don't "spec" them for the LT10.

DGDrls

[YellowHammer]

There's tons of good blade lube info on this forum, so I'll just say that I personally don't like pure water as blade lube on hickory.  I also certainly don't want to step on anybody's toes about blade lube, I'm just saying what works best for me.
As mentioned by others, Pinesol is good, especially if mixed with Murphy Oil Soap (a recipe I learned on this forum) but without a doubt, my favorite lube for hickory is water mixed with John Deere Cotton Picker Spindle Cleaner.  It is a tank mix concentrate especially designed to continuously lubricate and clean plant residue and field dirt/dust off the workings of extremely expensive cotton pickers.  I don't know how much money went into developing the stuff, but its a water based oil/detergent solution that will wet, clean, lubricate and stay on the band like nothing else I've used, because that's pretty much what it was designed to do on harvesting equipment.  I can also use less fluid to get proper lubrication and cleaning so the sawdust won't cake up as you are seeing. It lets me saw noticeably faster and with less wander in the big wood.
I've been sawing hickory for the last couple weekends, and should finish up tomorrow.  When dealing with hickory like in the photo, I want all the advantage I can get.  Can't wait to get done with it and into some nice soft white oak :D



 

[WDH]

That cotton picker spindle cleaner is very interesting.  I am going to call my John Deere Dealer and find out what it costs. 

[LeeB]

Share the knowledge when you find out please.

[YellowHammer]

John Deere Spinde Cleaner Solvent, AN114022, sold seasonally in $55 to $75 dollar, 5 gallon buckets in cotton country, a few big glugs per tank of water will do it.   Not real easy to get because they usually sell it by the pallet instead of by the bucket.   5 gallons of the concentrate will last me a long time because I don't use it for all my sawing, just when I'm pushing the saw and my normal blade lube can't keep up.   I found out about it from a guy who knows more about sawing than I ever will, did some web searches on the product, and have been using it since.  Pretty much all big farm machinery brands such as Case, Massey, etc that make cotton pickers have a similar water soluble oil/lubricant/cleaner and I assume they are equally effective, but I haven't tried them.  I bought some generic in a one gallon jug at our local Farmers CO-OP recently and it was almost as good.  Pretty cool stuff, if you turn on the lube when the band is not running, it doesn't just bead up and drop off the blade in an inch or two, it will stay on top and "run" down the blade, clinging to the metal.
YH

[WDH]

How does the cotton picker spindle cleaner do with heavy pine sap?

I checked with my John Deere dealer and a 5 gallon bucket of concentrate is $80. At the recommended mix, of 1.5 to 100, 5 gallons of concentrate will make 330 gallons of lube.  At $80, this is about $.25 per gallon or $1.25 for a 5 gallon lube tank.  Not too bad. 

[GeneWengert-WoodDoc]

Have you ever driven down the road in your car (older car, not the new ones with the antenna in the glass) and noticed the metal antenna is shaking and at certain speeds it gets a shake that is not random but in a pattern that makes the antenna look like it is warped?  What has happened it that the car has hit a resonant frequency for the antenna and so you get what are called standing waves on the antenna.

Well, with a sawblade, the same event happens.  At certain speeds, the mill hits close to the resonant frequency of the blade and so a wave forms on the blade.  If you are close to the frequency, the wave will move around the blade, but if right at the frequency, the wave will be stationary.  Normally, a blade and mill are not close to the same frequency.  In fact, with wider blades or larger diameters, we will add tension to the blade (band or circular; called hammering or tensioning or rolling) to increase the resonant frequency of the blade.  In this way, the low frequency of the mill will not be close to the high resonant frequency of the blade.  Where we can get into trouble is when a blade is heated, perhaps from working real hard or from sawdust spilling out of the gullet and rubbing the side of the blade, or when a small piece of wood gets wedged in along side the blade).  Heat, removes the tension that was in the blade and also causes the blade to temporarily expand; both lower the blade's natural frequency closer to the mill's frequency and creating blade movement when they get close. 

As might be expected, when you saw slowly (such as with a dense wood), you get finer sawdust and more likely to get spillage of this fine dust, especially compared to sawing more rapidly and getting a large chip that will be more likely to stay in the gullet.  (In fact, this is why some folks will find that "removing" every other tooth from a blade especially with a mill with less than adequate power, is helpful...a topic discussed in a posting a few weeks ago.)  Spillage means heat and blade movement, etc.

Hope this helps.  Questions?

[drobertson]

Interesting news Gene, and brings to mind what I noticed earlier this week.  While fueling up the mill and checking  a blade that I had come off the drive wheel, while adding some fluid to the tensioner, the blade had slipped off and got under a small bolt head between the pulley and shroud.  Thinking I might have damaged the band, I decided to run the mill with the covers off, I noticed the band ocsilating at the mid point between the two pulleys. My set screw in the middle of the head that goes under the body of the band had worn to a point allowing excessive ocsilating.  I readjusted to the recommended setting and all is good again.  One of the little checks that slipped by, even after I made the same adjustment on a friends mill not very long ago,

[GeneWengert-WoodDoc]

I forgot to mention, but maybe it was obvious, that the purpose of adding tension to a bandsaw blade is to change the natural resonant frequency.

Sometimes the guides will absorb enough energy to help cool the blade and stop oscillations.  In sophisticated, thin kerf saws, they will intentionally cool the blade.  We might use a cool lubricant to help in our mills.

[YellowHammer]

It works well in pine, although I usually use Pinesol in pine, unless I'm in a hurry.  I once had a rush job of a couple loads of pine I had to saw out real quick and the Pinsol lube couldn't keep the blade from getting too hot at the impatient feed rate I was sawing, so I poured some of this in the tank and the band ran noticeably cooler
I generally mix it heavier than the labeled concentration.
YH