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One of my new blades Broke today!

Started by flatrock58, August 05, 2015, 11:19:31 AM

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flatrock58

When I bought my mill last year it came with 20 old blades.  I bought 4 new blades to try and see if I could tell the difference in how they cut  and speed.  The old blades have been slowly breaking which it to be expected.  Yesterday One of the new blades that I have sharpened two or three times broke while cutting some pine.  After looking at the blade I notice another crack at the back of the blade.  What usually causes this kind of crack?  I have also noticed that most of the time I seem to break blades when the blade guide arm is closer to the closed position.


 
2001 LT40 Super Kubota 42
6' extension
resaw attachment
CBN Sharpener
Cooks Dual Tooth Setter
Solar Kiln

xlogger

are they about 1/4" away from the back of the roller guides?
Timberking 2000, Turbo slabber Mill, 584 Case, Bobcat 773, solar kiln, Nyle L-53 DH kiln

kelLOGg

All the cracks I have noticed start in the gullet.???
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

MartyParsons

Hello, "
Check the blade to roller flange adjustment. 1/16 on the drive side and 1/8" on the idle side. The first grove from the flange is about 1/8". A piece of wood or other stuff stuck in the saw head will also cause blade to over heat at the back.
Guide block plates can also rub the band and cause this.
Hope this helps.
Marty
"A pessimist sees difficulty in every opportunity; an optimist sees opportunity in every difficulty." -Winston Churchill

drobertson

It almost looks like you hit something hard and ferrous,  but it happens, wish it did not, but it does,
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,

hackberry jake

The choice of alloy used for the blade varies a lot depending on what is wanted out of the blade. If the blade is designed to be resharpened many times (long life) if will be a softer metal designed to flex more. If it is a one time use blade, like is used for high production pallet resaw systems, they will be much harder. Only designed to run for 4 or 5 hrs of hheavy sawing. The harder blades hold their cutting edges longer than the softer blades though. Maybe you have the harder type of blade and it just traveled around the wheels too many times.
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EZ Boardwalk Jr. With 20hp Honda, 25' of track, and homemade setworks. 32x18 sawshed. 24x40 insulated shop. 30hp kubota with fel. 1978 Massey ferguson 230.

Chuck White

I agree with Marty, the blade is likely too far forward of the flange on the blade guide rollers!
~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!

bkaimwood

I have had the exact opposite happen... The blade tracking rearward too far, and rubbing against the flange on the guide roller...this puts LOTS of heat in the back of the blade, as well as is the rollers..
bk

flatrock58

Thanks for the input.  I figured it could be a problem with the roller adjustment but wasn't sure.  They adjusted that a when I went to WM in Newnan about 100 hours ago, so I thought it would still be good.   I will check it and the other blades to see if they have any cracks.
2001 LT40 Super Kubota 42
6' extension
resaw attachment
CBN Sharpener
Cooks Dual Tooth Setter
Solar Kiln

drobertson

Quote from: drobertson on August 05, 2015, 02:30:06 PM
It almost looks like you hit something hard and ferrous,  but it happens, wish it did not, but it does,
I will say again, there is metal on that second tooth, on the top tooth in the picture is rounded as well,  the plus side to it all is it looks like you found it before it wound up behind the wheels, 
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,

flatrock58

I think the damage to the tooth must have been after the blade broke and hit the guard.  I had just sharpened this one and been sawing clear SYP with no metal.  I was cutting the cant into three  section to make 2x4's.
2001 LT40 Super Kubota 42
6' extension
resaw attachment
CBN Sharpener
Cooks Dual Tooth Setter
Solar Kiln

boscojmb

Quote from: drobertson on August 05, 2015, 02:30:06 PM
It almost looks like you hit something hard and ferrous,  but it happens, wish it did not, but it does,

It looks like Mr. Robertson hit the nail on the head. (pun intended)  :D :D :D

That sure looks like a minor metal strike that went unnoticed.

Cutting a small nail that is perpendicular to the blade, or soft metal like barbed wire, is sometimes hard to hear.

All blades that have a crack as substantial as the one in the picture make a TIC TIC TIC sound before they break.

It took me years to hear the TIC every time. I haven't had to fish a blade out from behind the band wheels (and everything else that a broken band can get tangled it) in some time. 

John B.

Log-Master LM4

Bluejay27

Quote from: boscojmb on August 05, 2015, 09:04:50 PM
Quote from: drobertson on August 05, 2015, 02:30:06 PM
It almost looks like you hit something hard and ferrous,  but it happens, wish it did not, but it does,
That sure looks like a minor metal strike that went unnoticed.

I've had minor metal strikes like that too. Either the blade breaks and has a minor strike with the blade guards (minor on all the teeth...) or I've screwed up and had the blade fall off (backing up in a cut with the blade still going) and it conveniently suddenly needs to be changed anyway.
'98 Wood-Mizer LT40HDD42 Super, '08 LT40HDG28, '15 LT70HDD55-RW, '93 Clark GPX25 Forklift, '99 Ford F550

customsawyer

Also check your b57 belts. Make sure they are not worn to the point of metal on metal.
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

Kbeitz

Opps....
Some how my posting ended up in the wrong message...

Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

flatrock58

Finally got a chance to look at the mill today.  The outside blade to roller flange adjustment was off.  The blade was actually against the flange.  not sure how that happened since it was just set a couple months ago at WM.  Got it all adjusted and will try it out tomorrow.  Thanks for all the input and advice.
2001 LT40 Super Kubota 42
6' extension
resaw attachment
CBN Sharpener
Cooks Dual Tooth Setter
Solar Kiln

Delawhere Jack

I agree with Marty and Dave's assessments, but beyond that, that blade is duller than dull. Those couple teeth in the photo are round. They should never get that dull. A band that needs to be sharpened should still be sharp enough to cut you if you handle it carelessly. Those teeth are WAY beyond time to be sharpened.

deadfall

I'm thinking those teeth bit some steel when the blade broke.  They look damaged, not dulled.
W-M LT40HD -- Siding Attachment -- Lathe-Mizer -- Ancient PTO Buzz Saw

============================

Happy for no reason.

Cedarman

Looking closely, I think you can see a curled piece of metal on the tooth.  That is what we see when a blade hits the shield when it comes off or breaks.  Also see it when you hit a nail.
Let us know if alignment makes a difference.
I am in the pink when sawing cedar.

flatrock58


Delawhere Jack I had only cut two logs since sharpening the blade on my CBN sharpener.  It was cutting smooth and fast when I had squared the cant.  The blade broke when I was cutting the cant in thirds.  The place it broke must have had a crack just like in the picture and it looked like it might have been cracked a little while.  Only the front half of the blade was a fresh clean break.  These logs were from the middle of the woods and I was cutting a log that was the third 12' log off the ground.  I guess I could have hit metal on an earlier log.  Anything is possible when cutting lumber!
2001 LT40 Super Kubota 42
6' extension
resaw attachment
CBN Sharpener
Cooks Dual Tooth Setter
Solar Kiln

Magicman

Looking at the dull teeth and curled metal, you definitely hit metal.  Pushing a dull blade will always lead to breakage.
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

flatrock58

 Well after all the post about dull blades I had to go back and look at the blade to make sure I wasn't going crazy.  There were only a few teeth that were badly dulled and a couple that had metal strikes either from the hitting guard after it broke or hitting metal.  All the other teeth appeared to me to be in fair shape.


 
2001 LT40 Super Kubota 42
6' extension
resaw attachment
CBN Sharpener
Cooks Dual Tooth Setter
Solar Kiln

Magicman

Quote from: flatrock58 on August 08, 2015, 10:31:23 AMI had to go back and look at the blade to make sure I wasn't going crazy.
I agree, you ain't crazy.
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

deadfall

Looking there, and especially at the tooth between your fingers, at this resolution, I see what looks like a darned good point.  I suspect you didn't break because of dull.  There are so many other factors, that I can't make any guess about why it broke.  But I don't think it was not being sharp. 

W-M LT40HD -- Siding Attachment -- Lathe-Mizer -- Ancient PTO Buzz Saw

============================

Happy for no reason.

drobertson

I need to clarify to flatrock,  I surely did not mean the break was caused by a hit, just noticed a hit,  I've had brand new straight from the box give way, so, it happens, change out, and move on,, on the crazy thing,, I think we all are just a bit on the crazy side ;D
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,

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