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Broken Bands

Started by bandmiller2, May 04, 2008, 07:24:31 AM

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bandmiller2

Do most of you guys run bands until they break??I catch about half before when sharpening,the fine cracks ,usally in the center of the band.Its sure  tough on your shorts when they break on the mill.
A man armed with common sense is packing a big piece

Tom Sawyer

My bands usually go about 8-10 sharpenings before they break.  I have yet to find any cracks, but that may be due to not paying close enough attention ::)

Tom

If I find damage I can't fix, I pull the band.   Otherwise, I run them till they break.

WH_Conley

I look at them when sharpening, seldom find a crack, usually break on the mill. Sometimes they get too thin to sharpen.

Thought on disposal. When I get a big pile I can sell them here at the local salvage for "short iron" if broke up less than 4', if I come up with an old car body I just shove them in. Most of the time it is not worth the hassle and I just give them to somebody to get them out of the way.
Bill

cantcutter

I put mine to the curb when they are done, they don't last very long with all the scrap vultures around lately.

I find that they last longer if you don't put them under the pressure of sawing two different grains at the same time. i.e. taking a slab that needs trimming off of the top and placing it on the side of the cant while you make the next cut.


mike_van

I look at mine when they come off the mill, if I see a crack, even 1/8", I scrap it - Waste of time to me to have a fresh sharpened blade break on the 1st or 2nd cut.  Mine tend to get cracks on the back edge, not the gullet side.  And yes, with the electric mill [quiet] there's quite a BANG when one lets go.
I was the smartest 16 year old I ever knew.

Tom

Mike,
Cracks in the back of the band are a sure fired diagnosis for the lip on a roller guide or the back roller on static guides to be too far back.  They are there to give beam strength to the band.  If the band is bent too far backwards when sawing under pressure, those cracks will develop in the back of the band.

Perhaps you might take a look at your guides.  If this is the case, and this diagnosis is true, you might get some more mileage from your bands by adjusting the roller or support bearing forward to within 1/16 of the back of the band.  :)

The only contact the back of the band should have with the lip or back bearing is when under sawing pressure.

mike_van

That clearance is something I need to pay more attention to Tom, ususally it's too much - I get what I think is good life from my blades, 8 to 12 sharpenings, but it would probably be even better with a little more diligence on my part.
I was the smartest 16 year old I ever knew.

Tom

It's kind of hard to argue with 8 to 12 sharpenings.  :D

Tony

    I really hate to shut this thread down (i have a knack for killing a thread, don't know why or how) but have you ever watched a customer jump when a band breaks smiley_horserider smiley_horserider smiley_horserider



                                                  Tony   (aka threadkilla)       8)
TK1600, John Deere 4600 W\frontendloader, Woodmaster718 planer\moulder, Stihl MS461 Stihl 036 & 021 & Echo CS-370
"You cannot invade the mainland United States.  There would be a rifle behind each blade of grass."  Adm. Isoroku Yamamotto ( Japanese

Haytrader

 ::)
Tony,

I am better at it than you.

;)
:D
Haytrader

pigman

I love it when a band breaks with a loud bang , the customer jumps and then asks if he has to pay for the blade. ;D
See Tony, you haven't killed the thread yet, but I bet if you post one more time the the thread will just die. ;) :D
Things turn out best for people who make the best of how things turn out.

Tony

Quote from: pigman on May 05, 2008, 11:49:07 AMSee Tony, you haven't killed the thread yet, but I bet if you post one more time the the thread will just die. ;) :D


   I just can't stand it  :D :D :D   must post ,must post  ;D :D ;D :D ;D


                                                     Tony  8)
TK1600, John Deere 4600 W\frontendloader, Woodmaster718 planer\moulder, Stihl MS461 Stihl 036 & 021 & Echo CS-370
"You cannot invade the mainland United States.  There would be a rifle behind each blade of grass."  Adm. Isoroku Yamamotto ( Japanese

ADAMINMO

That is very odd!!! I though I was the only one that could post and no one ever replys again!!! I am relieved that it ain't just me, I thought everyone was shunning me.But I guess if this thread gets no more responses then I will know no one likes me. :'(  :'(  :'(  :'( Plus it is reply # 13 on this thread ..... That can't be a good omen!!!! ( I am posting in as many threads as I can to test this theory!)

Tom

I hate it when a band breaks.  I jump 3 ft, yell and it's all I can do to keep from wetting my pants.  Not to mention the  $'s flying away.

You whippersnappers haven't been around long enough to earn being ignored yet.  Not as long as I can type, anyway.  You too, Haytrader.   

Adam! you kill this thread and I'll chase you to New York City.  You'll have an excuse then.  They won't be able to understand you.  :D

See, Tony. Pigman was right ;D  If you give him a good "listening to",  he'll l'arn-ya somthin'. :D :D

Tom Turkey Talkin' Here.

mike_van

The customer isn't the only one that jumps a little!  :D  I've learned 2 "warning" signs, but you gotta be quick - One is the band will start shucking back & forth, even in the cut, when there's a gullet crack, the front edge of the blade becomes a little longer than the back, makes this happen. The second is a ticking sound, I don't know if you'd ever hear it with a gas or diesel mill. It won't tick long, then there's a big bang.  :o I use C.I Wright guides, I'm pretty sure the ticking is a crack on the back edge of the blade, hitting the thrust wheel everytime it comes around.  With either of these, I learned to not even try to finish the cut, you ain't going to make it - 
I was the smartest 16 year old I ever knew.

ADAMINMO

Looks like this thread is still goin strong so I guess I didn't kill it!!! 8) 8) 8)
Now I won't have to worry about Tom chain me to NYC and everyone will still understand me.Guess that my theory is busted. :D :D :D

solidwoods

Unfortunately my mill is designed so that a broken blade can strike the drive belt and nick it.
I catch most breaks during the cut- the tell tale click click or fore/aft flutter.
My mill has all steel wheels.

For Lemon aid-
1 steel post 10' long +/-
A whack of broken blades.

Stand the post vertical and weld on to it the broken blades.
Make a broken blade tree.
Sell it for $XXXX.00

jim
Ret. US Army
Kasco II B Band mill
Woodworking since 83
I mill & kiln dry lumber, build custom furniture, artworks, flooring, etc.
If you mill, you'll be interested in some of my work in one way or another.
We ship from our showroom.
N. Central TN.

DWM II

I pulled this up to keep from starting yet another thread on broken bands. Im having some trouble with with my bands now, they are cracking in the gullets about 3/16 from the tooth, the flat area of the gullets. These blades are brand new and cutting great sawing SYP, the frustrating part is they are still sharp when they break. Im not having to "push" too hard and there is no tattle tale before they go. I am running some older B-57s (Gates crowned) but they appeat to be in good shape. Should I try replacing these? The cant adjustment on the idle side is in proper adjustment, the gullet is 1/8 to 3/16 ahead of the wheel and my guides are running at 1/16 from the back of the blade unengaged in wood.

any ideas?
Stewardship Counts!

adrean louis

being a S O B ( son of blacksmith) that almost sounds like to hard of metal problem.

Tom

Pushing the blade too hard into the wood will stress the gullet there and break the band.  If you aren't doing that, it could be a misground gullet, a mistempered band, or if breakin gat the weld, a bad weld.

Other than that I can't think of much that you could be doing to cause it to break. Cracks are the result of work hardening.  If the band is still sharp then you aren't running them too long.   Just because it feels sharp, doesn't mean that it is.  If the tip of the tooth and its corners are shiny, it is dull, or dulling.

When cutting steadily all day on a 1000 to 1500 bd ft. day I would change bands twice and sometimes three times, almost always at noon after a 4 hours of sawing and 400-600 board feet.  If I continues just because the band was cutting, I ended up damaging the band.

Perhaps the band slipping on the wheels might generate enough heat to work harden it.

Look at the metal beside the V on the wheel.  If you see shiny spots, the band is hitting the wheel because the belt is compressed or worn or the V is worn and not  holding the belt up.   The band hitting the wheel will break the blade. Change the belts.

DWM II

I'll look at the wheels real hard and make sure the bands arent hitting the wheels. Whats the consensus on crowned vs. flat belt profiles? I've been running crowned for 3 years with no issues but cant say what WoodMizer recommends. These bands are brand new, not resharps and I would gladly change them out at 400 bdft if they could get there, last band broke at 270bdft.





Stewardship Counts!

Tom

I'm no consensus, but I'd want the most belt I could get and I guess that would be crowned.  The purpose is to provide a tire that will control the band.  The band follows the crown.  The less the crown, the less control is imparted.  Unlike automotive uses, strength doesn't count that much.  The life of the belt comes from it's inability to be compressed and the tenacity of its wearing surface.  From time to time, the preferred belts have been    Browning and Gate

DWM II

The Gates that are on there are three years old so I'll go back with them. Thanks Tom.
Stewardship Counts!

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