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Blade Rise

Started by homesteader1972, June 16, 2015, 04:49:29 PM

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homesteader1972

Hello All,

I have had some instances where the blade wants to rise when entering the the log. Not always, but more than I would like, and more so on some wide logs. The mill is in alignment, and the blade guides are level, using the WM tool.  What else should I be looking at?

Thanks much
Woodmizer LT40HD20G

ladylake


  Try less hook, 10° seem to do that unless really sharp.   Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

shenandoahsawmill

A wide bandmill should do the trick. I fought the problem for years but when I switched from a WM 1.25" wide blade on an LT 30 and bought a wide bandmill with a 5" wide band, my wavy board and diving/rising problem went away even on very wide cuts. I also doubled my carriage speed. A wide band has considerably more resistance to climbing or diving due to it's ability to stay straight and not twist as it is being pushed through the log. You can also tension the heck out of them and this helps too. Of course the wide band has it's drawbacks and that would be the cost of the mill and bands and support equipment to maintain the bands but if you want non wavy (very consistent) board thickness it is worth considering. Look for used equipment on sawmill exchange.

VT-Woodchuck

I was given a couple of good Red Cedar logs and I wanted to make sure I did a good job for 1/2" paneling. I put on a new blade and started to cut. After the second cut, I decided that cedar knots were harder Than anything else I have sawn. Next was a hemlock and it was terrible! At least a quarter of an inch off at every knot. I, AGAIN, checked every thing out and decided to put on an old blade that had been hanging in a tree all winter. It cut great!  My point to this story is to start simple and increase the complexity of problem solving. The trade new blade was terrible (I don't know why) and the old dull, rusty blade was so much better.

POSTON WIDEHEAD

A SHARP blade will enter the log straight as an arrow.
Once a blade begins and I repeat, BEGINS to get dull, this will be the first thing you will notice...the entry cut.
The blade will actually bend a little pointing the teeth upward and will straighten out once it enters the log.
Thus you will have a hump at the end of each board where the blade entered.
Once a blade starts this, you can slow your entry into the log and I mean slow, to give the blade a chance to straight cut its way into your log.
The wider the cut, the slower you need to enter the log. :)

Note: I ALWAYS use a 4° blade on everything I saw......nothing else.
The older I get I wish my body could Re-Gen.

MartyParsons

Hello,
The most common thing I see in the field on customer mills is the drive belt is not at the proper tension. You will find if the engine drive belt is loose it will ( slip) and slow the band speed down when it enters the log and when it exits the log. Most logs are drier at the ends because moisture is removed from air moving over the exposed ends. When the band speed is changed in the cut you will get a wave at the start of the cut and even if there is a defect when the blade cuts against the grain or defect.

That would be my first check if the blade is diving in the beginning of the cut.
Hope this helps.
Marty
"A pessimist sees difficulty in every opportunity; an optimist sees opportunity in every difficulty." -Winston Churchill

John Bartley

Without exception, every time I have had a problem with waves or blade lift on entry, the problem has been an incorrect set on the teeth. My experience has been that a properly set,but not sharp blade will cut straight and slow. An improperly set, but nice and sharp blade will wave no matter how slow you cut.
Kioti DK35HSE w/loader & forks
Champion 25hp band mill, 20' bed
Stihl MS361
Stihl 026

shakebone

Check your belts on your wheels and drive belt tension
Lt40 super desiel , LT 35 hyd , New Holland ls 180 , Case 75xt ,
So many logs so little time.

Rachiano

What about blade flatness? John Bartley mentioned something regarding set....I was wondering...if a blade that is not flat (that has the anticlastic curvature) is being set...the set may be inacurate? I am thinking about investing in a band roller from cooks....people that use the cooks band roller please give some feedback if it helped solving the wave problem.
Rachiano

WM LT70
WM EG50
Werklust WG25 Wheel loader
DAF 2100 HIAB truck

Chuck White

Band Rollers, some swear by them, some swear at them.

I've never had issues with flatness, I sharpen my own bands and usually get 8-10 sharpenings on my bands before I get a cracked or broken band!
~Chuck~  Cooks Cat Claw sharpener and single tooth setter.  2018 Chevy Silverado and 2021 Subaru Ascent.
With basic mechanical skills and the ability to read you can maintain a Woodmizer  LT40!

5quarter

Ditto the above comments. You may also want to try entering your cut at or near your regular sawing speed. Blades are not designed to creep through a cut, whether your entering exiting or somewhere in the middle.    Also, Martys suggestion is right on. Drive belts need to be tight.
What is this leisure time of which you speak?
Blue Harbor Refinishing

John Bartley

Quote from: 5quarter on June 17, 2015, 01:44:57 AM
Ditto the above comments. You may also want to try entering your cut at or near your regular sawing speed. Blades are not designed to creep through a cut, whether your entering exiting or somewhere in the middle.    Also, Martys suggestion is right on. Drive belts need to be tight.

I agree.  Unless there is some reason not to, I tend to enter the cut at approximately what I think the cutting speed will be.
Kioti DK35HSE w/loader & forks
Champion 25hp band mill, 20' bed
Stihl MS361
Stihl 026

homesteader1972

Quote from: POSTONLT40HD on June 16, 2015, 06:06:34 PM
A SHARP blade will enter the log straight as an arrow.
Once a blade begins and I repeat, BEGINS to get dull, this will be the first thing you will notice...the entry cut.
The blade will actually bend a little pointing the teeth upward and will straighten out once it enters the log.
Thus you will have a hump at the end of each board where the blade entered.
Once a blade starts this, you can slow your entry into the log and I mean slow, to give the blade a chance to straight cut its way into your log.
The wider the cut, the slower you need to enter the log. :)

Note: I ALWAYS use a 4° blade on everything I saw......nothing else.

I also use some 4deg blades, but was having this issue with the 9's. Are you having better success with waves using the 4's.

Thanks
Woodmizer LT40HD20G

homesteader1972

Quote from: John Bartley on June 16, 2015, 08:06:09 PM
Without exception, every time I have had a problem with waves or blade lift on entry, the problem has been an incorrect set on the teeth. My experience has been that a properly set,but not sharp blade will cut straight and slow. An improperly set, but nice and sharp blade will wave no matter how slow you cut.

Are you calling incorrect set, too much, too little, uneven or something else? I have been setting my own bands and would think they are pretty even on the set. But I have increased the set a little. Could too much set cause this?

Thanks
Woodmizer LT40HD20G

homesteader1972

Quote from: MartyParsons on June 16, 2015, 07:03:38 PM
Hello,
The most common thing I see in the field on customer mills is the drive belt is not at the proper tension. You will find if the engine drive belt is loose it will ( slip) and slow the band speed down when it enters the log and when it exits the log. Most logs are drier at the ends because moisture is removed from air moving over the exposed ends. When the band speed is changed in the cut you will get a wave at the start of the cut and even if there is a defect when the blade cuts against the grain or defect.

That would be my first check if the blade is diving in the beginning of the cut.
Hope this helps.
Marty

I have not checked this in a while and may be part of the problem. An issue I have had with setting the belt tension is that, at least for me, is that if I set the tension while the belt is cool, then when things warm up the belt is too loose. So, the last I time ran the mill a bit then set it. Is that normal? After that, it was noticeably harder to engage when cold, but not so bad when warm. It may need an adjustment as it doesn't feel any harder when cool now. I will check it tomorrow morning.

Thanks much
Woodmizer LT40HD20G

ladylake

 
With nice tight belts and a 10° blade that is not real sharp I'll get that nasty  rise on entry on wide cuts, even narrow cuts on frozen or hard to cut wood .  4° is no where near as bad and that all I run after they are sharpened the first time. If I buy them a 10° they are used to cut easy to cut wood.  Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

barbender

Some of my worst waves were due to improper belt tension. Actually, my triple cog belt had worn enough that it was bottoming out without fully engaging the pulley, so even though the tension was right, the belt was still slipping. Even with a new belt, I feel getting proper tension on a WM is a bit of a dance. I think the factory specs are just barely tight enough, they are set were they are more to keep from breaking a crankshaft, I would run my belt tighter if I wasn't afraid of that.
Too many irons in the fire

ladylake

 Surly loose belts will cause waves and most likely along the whole log unless you are feeding way to slow.  Steve
Timberking B20  18000  hours +  Case75xt grapple + forks+8" snow bucket + dirt bucket   770 Oliver   Lots(too many) of chainsaws, Like the Echo saws and the Stihl and Husky     W5  Case loader   1  trailers  Wright sharpener     Suffolk  setter Volvo MCT125c skid loader

gimpy

Quote from: MartyParsons on June 16, 2015, 07:03:38 PM
The most common thing I see in the field on customer mills is the drive belt is not at the proper tension. You will find if the engine drive belt is loose it will ( slip) and slow the band speed down when it enters the log and when it exits the log.

That would be my first check if the blade is diving in the beginning of the cut. Marty

Marti,

In my case, my blade was rising significantly. An actual bow in the blade. I will now check the belt tension. I shut down to get an answer and to fix the problem before I continue cutting.

However, I also noticed that the blade tension kept loosening up. I'd adjust it and bring it back up and cut a couple boards and it's down a bit again. What could be causing that? I am frustrated at being so new that I can't figure this out myself yet. However I will check my belt tension.
Gimpy old man
Lucky to have a great wife
John Deere 210LE tractor w/Gannon Box

gimpy

Update:

Checked the belt tension with my belt tension tool. It is right on. As I expected since I only have 5-7 hours on it since Woodmizer, Oregon set it. But cleaned things up, replaced the blade, swapped the blade belts and am on the way out to finish the two cuts I have left. Then I'll put on another log and see how things work.

I'm still baffled by the blade tension pressure decreasing. But with the new blade and all, we'll see how things work.

Still trying to learn how to determine the correct feed speed.
Gimpy old man
Lucky to have a great wife
John Deere 210LE tractor w/Gannon Box

pineywoods

Gimpy, the blade tension drops because the blade is heating up and expanding. This is pretty much normal after mounting a new blade and should stabilize after a few cuts. If it doesn't, look into what's heating the blade, not enough set when cutting softwoods, incorrect guide roller alignment causing the blade to rub on the kerf, blade tracking off, any thing that will heat the blade..Most of the time, it's a dull blade being pushed back against the shoulder on the guide rollers.
1995 Wood Mizer LT 40, Liquid cooled kawasaki,homebuilt hydraulics. Homebuilt solar dry kiln.  Woodmaster 718 planner, Kubota M4700 with homemade forks and winch, stihl  028, 029, Ms390
100k bd ft club.Charter member of The Grumpy old Men

gimpy

Now that I replaced the blade with a new sharp blade, no problems. I know about a new blade needing to set in and need to tighten the tension.

But I was having a problem with an older blade with a few hours on it. Perhaps it was just dull. I'm going to cut another log tomorrow and I'll see if any of my prior complaints are still valid.

Thanks for the help.
Gimpy old man
Lucky to have a great wife
John Deere 210LE tractor w/Gannon Box

Kbeitz

I'm just a newbe but everything I read says if your blade it getting hot you will loose your tension .
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

LittleJohn

Quote from: Kbeitz on June 25, 2015, 04:58:23 AM
I'm just a newbe but everything I read says if your blade it getting hot you will loose your tension .
As piney wood said above, a small lose in tension is expected after switching to a new blade.

...and yes metal expands as it is heated; hell everything expands a little bit when heated  ;D

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