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Importance of accurate mill alignment

Started by Percy, February 06, 2016, 11:02:30 PM

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Percy

My 2003 LT70 is somewheres between 9000-10,000 hours on the meter. When the mill was new,I was anal about pretty much everything to do with maintenance and alignment etc. My manual recomends a total major alignment every 1500 hours. I kept records till 4500 hours. Bein old and senile, I cant remember if I done a major since then. I regularly adjust the roller guides with the blade alignment tool and make sure they are within factory specs. For the most part, the mill cuts great.......cept when I started cutting 2 x20's out of sitka spruce. Sitka is the most miserable wood available in my part of the world to cut. No matter how carefully I set and sharpened, and adjusted roller guides. I could not stop the wave.....I was choked, after all these years of cutting, I was making worse boards that on my first day 20 years ago :-[ :-[. I decided to do a major alignment, realizing when I checked my records that it had been a while.....heh.... Well the mill was in pretty accurate shape cept for band wheel alignment and tracking( i had the band running too far back but not enough to affect set). The biggest problem was the band wheels were not in the same plane. Took a little effort and time to get it right. After I got it right, the sitka cut like Birch...strait and accurate...no more wave.

I feel like I have a good understanding of how this mill works.....but it escapes me, why the blade cut wavey. Even though the guides were "fixing" the wheel alignment condition, it would not cut right on a tough cutting species such as Sitka spruce with a properly sharpened and set blade. All around feed rates are way up after this alignment......

Opinions from you engineer types.......enlighten me...
GOLDEN RULE : The guy with the gold, makes the rules.

kelLOGg

Quote from: Percy on February 06, 2016, 11:02:30 PM
The biggest problem was the band wheels were not in the same plane. Took a little effort and time to get it right.

Any idea how that happened and more importantly, how did you correct it?
Bob
Cook's MP-32, 20HP, 20' (modified w/ power feed, up/down, loader/turner)
DH kiln, CatClaw setter and sharpener, tandem trailer, log arch, tractor, thumb tacks

customsawyer

Two LT70s, Nyle L200 kiln, 4 head Pinheiro planer, 30" double surface Cantek planer, Lucas dedicated slabber, Slabmizer, and enough rolling stock and chainsaws to keep it all running.
www.thecustomsawyer.com

homesteader1972

Quote from: kelLOGg on February 07, 2016, 06:27:32 AM
Quote from: Percy on February 06, 2016, 11:02:30 PM
The biggest problem was the band wheels were not in the same plane. Took a little effort and time to get it right.

Any idea how that happened and more importantly, how did you correct it?
Bob

What does that mean, not in the same plane? My WM manual does not address that, at least not in the same terms.

Thanks
Woodmizer LT40HD20G

4x4American

Boy, back in my day..

dgdrls

Co planar would be the term meaning to operate in the same plane,
So using a straight edge the face of the first wheel would project exactly to the face of the second wheel


 

I got some theories on this but I need to think them through more.
I find these kinds of challenges really interesting,

Dan

Percy

I am using .050 x 1.5 x184 x 13 degree blades. My manual doesent really say "same plane" as well. Im making assumptions that the proceedure they describe does that .
With a new belts and a new blade on, and tracked, while the blade guides are removed, the blade is aligned parellel to the bed. This was the adjustment that was waaaaayyyyy out on the drive side. At about 8000 hours, I replaced the large (worn out) driven pulley and must have knocked things outta whack then. I should have checked then but didnt. Regardless, the mill is working better than I expected since that adjustment. Still, Im at a loss to the forces that would cause  the blade to wave while this adjustment was wonkey...
GOLDEN RULE : The guy with the gold, makes the rules.

drobertson

Did you notice a higher blade breakage while out of alignment? or any at all or just the usual once in a while?  I'm thinking, just a shot in the dark and don't matter now, but if the blade was constantly trying to get to a normal, even plane, seems like it could cause some possible wave,  but it's nice when things start clicking!  High speed low drag,,
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

Percy

Quote from: drobertson on February 07, 2016, 01:52:23 PM
Did you notice a higher blade breakage while out of alignment? or any at all or just the usual once in a while?  I'm thinking, just a shot in the dark and don't matter now, but if the blade was constantly trying to get to a normal, even plane, seems like it could cause some possible wave,  but it's nice when things start clicking!  High speed low drag,,
I was/am getting good life out of my blades. One thing I did notice on the waves was where the blade entered the log/cant, the cut was not nearly as wavey as it was on the output side(drive side). This was the side that was out of adjustment.
GOLDEN RULE : The guy with the gold, makes the rules.

terrifictimbersllc

Could be the band is going off the roller in the compromised alignment situation, the 1/4" down pressure isn't enough,  do you have lower guide blocks in place?
DJ Hoover, Terrific Timbers LLC,  Mystic CT Woodmizer Million Board Foot Club member. 2019 LT70 Super Wide 55 Yanmar,  LogRite fetching arch, WM BMS250 sharpener/BMT250 setter.  2001 F350 7.3L PSD 6 spd manual ZF 4x4 Crew Cab Long Bed

Percy

Quote from: terrifictimbersllc on February 07, 2016, 04:17:05 PM
Could be the band is going off the roller in the compromised alignment situation, the 1/4" down pressure isn't enough,  do you have lower guide blocks in place?
I dont use the blocks anymore. They were just a trap for small shards of wood heating the blade up to the point of smoking. The guides on a 70 are different than on the super hydralics Ive seen. I think the Supers guides are better than the 70 type for this reason. Regardless, your theory makes sense. Even with no blocks in, my band cannot come off the back of the guides or band wheel as the design of the guide wont let it.
GOLDEN RULE : The guy with the gold, makes the rules.

dgdrls

Quote from: Percy on February 07, 2016, 04:13:54 PM
Quote from: drobertson on February 07, 2016, 01:52:23 PM
Did you notice a higher blade breakage while out of alignment? or any at all or just the usual once in a while?  I'm thinking, just a shot in the dark and don't matter now, but if the blade was constantly trying to get to a normal, even plane, seems like it could cause some possible wave,  but it's nice when things start clicking!  High speed low drag,,
I was/am getting good life out of my blades. One thing I did notice on the waves was where the blade entered the log/cant, the cut was not nearly as wavey as it was on the output side(drive side). This was the side that was out of adjustment.

Percy I'll guess you had to readjust the guides when you were done aligning the wheels?

I suspect the dimensional section loading was not the same from wheel to wheel on the band and changed as the band moved
from wheel to wheel back and forth.
As you indicated the wave was worse on one side than the other,

Pretty amazing that you can put 55 diesel HP or the electric equivalent 
driving one of these blades without an issue  but if your out of alignment
even a bit it shows up in the final product,

Thanks for sharing your experience

Dan








MartyParsons

Hello,
  I think when you go through an alignment procedure when things are not working well. ( usually when the logs freeze or you get some ugly logs with lots of defects or some difficult sawing like Hickory or the Spruce ) Things show up that you may not have noticed before. There may be some of these things that are worn or just needing adjustment.

  • Drive or Idle side wheel belts worn or steel wheels out of crown

  • Tracking on the blade (  I like to see the band centered on the wheel belt favored back more then forward)
  • Blade guide arm loose and out of adjustment


  • Roller guide assemblies worn or out of adjustment
  • and the list may go on
The most common thing I see in the field is a loose drive belt and the blade guide arm out of adjustment.

I guess what I am saying is I ask myself the same questions when I arrive and when I leave a sawmill operation.

What are the problems I need to address while I do an alignment?

I ask the mill operator to test cut with every mill before I leave. It is great if they hang that blade and mark TEST blade. When the mill starts to do strange cuts. Start with the Test blade.

Another tip is to measure the head to bed ( saw blade to bed rail)  measurement before you start. I do this from time to time if I am not sure what the problem is. That way you have a base line to start. So check the blade tilt then the deflection. If everything was in spec you need to look other places to resolve the issue.

I hope this helps.

Marty



[/list]
"A pessimist sees difficulty in every opportunity; an optimist sees opportunity in every difficulty." -Winston Churchill

Percy

    Quote from: dgdrls on February 08, 2016, 07:22:53 PM


    Percy I'll guess you had to readjust the guides when you were done aligning the wheels?

    I suspect the dimensional section loading was not the same from wheel to wheel on the band and changed as the band moved
    from wheel to wheel back and forth.
    As you indicated the wave was worse on one side than the other,

    Pretty amazing that you can put 55 diesel HP or the electric equivalent 
    driving one of these blades without an issue  but if your out of alignment
    even a bit it shows up in the final product,

    Thanks for sharing your experience

    Dan









    Oh yes. The band wheel was leaning enough that to do a proper "guide off" blade to bed alignment, I had to back the brake off as it was causing erratic results from the adjusting. Once that was done, while the guides are still off, aligning the saw-heads "sideways tilt" was next, followed by bedrail alignment, and then put the guides back on and adjust them properly( the guides are fairly complex on my 70 compared to my old 97 LT40).



    Quote from: MartyParsons on February 08, 2016, 09:22:42 PM
    Hello,
      I think when you go through an alignment procedure when things are not working well. ( usually when the logs freeze or you get some ugly logs with lots of defects or some difficult sawing like Hickory or the Spruce ) Things show up that you may not have noticed before. There may be some of these things that are worn or just needing adjustment.

    • Drive or Idle side wheel belts worn or steel wheels out of crown

    • Tracking on the blade (  I like to see the band centered on the wheel belt favored back more then forward)
    • Blade guide arm loose and out of adjustment


    • Roller guide assemblies worn or out of adjustment
    • and the list may go on
    The most common thing I see in the field is a loose drive belt and the blade guide arm out of adjustment.

    I guess what I am saying is I ask myself the same questions when I arrive and when I leave a sawmill operation.

    What are the problems I need to address while I do an alignment?

    I ask the mill operator to test cut with every mill before I leave. It is great if they hang that blade and mark TEST blade. When the mill starts to do strange cuts. Start with the Test blade.

    Another tip is to measure the head to bed ( saw blade to bed rail)  measurement before you start. I do this from time to time if I am not sure what the problem is. That way you have a base line to start. So check the blade tilt then the deflection. If everything was in spec you need to look other places to resolve the issue.

    I hope this helps.

    Marty



    [/list]
    Pretty much sums up how I addressed the problem. I got very fussy with my adjustments getting them as accurate as possible. I thought the mill was performing well prior to the alignment(2x20's not withstanding....heh) but the mill now is much more accurate and feed rates in the Western Red Cedar is faster than I thought it could be(Im old and my memory dont work like it used to). 

    Still I wonder why, even with good blades and properly adjusted blade guides, how a mis aligned bandwheel can cause wave. Regardless, its a good lesson for me to keep things adjusted properly and in the correct sequence as opposed to "fixing it with the guides" as I was doing prior to this.
    GOLDEN RULE : The guy with the gold, makes the rules.

    Ga Mtn Man

    Imagine that you continued to tilt one of the band wheels further and further.  Eventually you would get to a point where one edge of the blade lifts of the roller guide.  Even a small amount of band wheel tilt will cause a front to back pressure differential on the guide.  As I recall, Cook's tilts their band wheels slightly forward so that there's a little more pressure on the back of the blade at the guides, in theory keeping the blade more firmly "attached" to the guides.     
    "If the women don't find you handsome they should at least find you handy." - Red Green


    2012 LT40HDG29 with "Superized" hydraulics,  2 LogRite cant hooks, home-built log arch.

    fishfighter

    Quote from: Percy on February 07, 2016, 12:03:43 PM
    I am using .050 x 1.5 x184 x 13 degree blades. My manual doesent really say "same plane" as well. Im making assumptions that the proceedure they describe does that .
    With a new belts and a new blade on, and tracked, while the blade guides are removed, the blade is aligned parellel to the bed. This was the adjustment that was waaaaayyyyy out on the drive side. At about 8000 hours, I replaced the large (worn out) driven pulley and must have knocked things outta whack then. I should have checked then but didnt. Regardless, the mill is working better than I expected since that adjustment. Still, Im at a loss to the forces that would cause  the blade to wave while this adjustment was wonkey...

    I would have to say vibration with the wheels out of line and that your guides were masking the vibration. One way to check in the future is by taking a long screwdriver, place it to different areas around the wheels when running and have the screwdriver handle to your ear. You might not feel the vibration, but will hear it.

    4x4American

    Quote from: Ga Mtn Man on February 09, 2016, 07:35:05 AM
    Imagine that you continued to tilt one of the band wheels further and further.  Eventually you would get to a point where one edge of the blade lifts of the roller guide.  Even a small amount of band wheel tilt will cause a front to back pressure differential on the guide.  As I recall, Cook's tilts their band wheels slightly forward so that there's a little more pressure on the back of the blade at the guides, in theory keeping the blade more firmly "attached" to the guides.   

    Typing from memory, I believe that Cook's tilt their band wheels 3/32" foward.  Cook's has a great section on their website that Dan posted a link to earlier if you thumb around in there they have info on the subject, but I believe I got the 3/32" number from one of their videos.  It is one of their six items necessary to cutting accurate lumber productively.
    Boy, back in my day..

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