HELP----Breaking Blades

[Steve_M]

I have been breaking blades at an alarming rate lately.  In the last 3000bf I have cut I have broked 12-15 blades.

1) All blades ar WM DoubleHard 10deg.  Half new, the other have been through Resharp one time.

2) Cutting 3 year old Walnut, 2 year old Cherry, 1 year old Soft Maple.

3) Usually break after 100-200bf.  About the same for all types of wood.

4) I do notice a little build up oin the blades using the LubeMizer at about half speed(just use water and windshield wiper cleaner).

5) I do notice a little heat in the drive side roller.

6)  I put on new B-57 and am still breaking blades.

7)  I do hear noticable noise from the blades and or guides.

8)  I am able to eliminate the noise if I flood the blade with water, but it makes a huge mess.

9)  Blade tracking and alignment all seem ok.


What am I missing here???

Could my roller be giving too much deflection?  Could my hydraullic tension guage be allowing me to adjust the blade to tight?

Any thoughts, experiences, or advice would be welcommed.

Thanks

Steve

  

[Percy]

Heya Steve
The fact thar they are breaking new makes me think the tension is waaaay tooo high or somthing is massivly out of adjustment.  The blades can take alot of abuse for their  first couple of uses. Bummer about it. Hope you getter figured.

[Minnesota_boy]

Check youir blade guide rollers and see if the flange has the proper clearance from the back of the blade.  I've had them slip their adjusters a few times and move back, allowing too much blade deflection.

[Norm]

What are you running for tension Steve? When I used to run the tension higher I would break more. Now I run in the yellow-red area. Usuallly in the yellow if not real wide cuts. The noise makes me think it's in your roller guides. The one on the movable arm can get out of wack. Put about 500 on the tension remove the covers and move the blade by hand. with the idler wheel. Check how your blade runs on the guides when doing this. There is a piece of metal on the drive side roller guide the blade runs through. Pretty small gap, check it too. Good luck.

[FeltzE]

How old is the saw?

If you've bee out in the weather and have over 1000 hrs on the mill I'd check the roller guides make sure their bearings are ok and that you have no flat spots on the guides.

Second If I have been running other blades without problem I'd go back to a different blade and check the blade life. A fellow with a brand new WM came by with it to saw his firs logs here and had an awfull time with the double hard blades breaking straight out of the package without finishing a log. I put my blades on the mill and everything was fine. I have subsequently tried the double hards and found I get poorer life out of them due the the fatigue on thicker metal but otherwise a great cutter.

All else fails realign the guides and head like mentioned earlier.

I sharpen my own so I can't speak for the resharp service. I f I do, its a whole 'nother discussion thread on why.


Good luck

[EZ]

I was having blade breakage problems last summer, all the blades were breaking at the weld. I gave the guides a quick check and they seem ok. But in my mind I thought for sure that my blade man was doing something wrong with the welding. I had a few nasty words to say to him and he finally gave me some new blades, but they broke too. I went with a different brand and they were breaking too. :-[ ??? I check my guides again with care and the one was 1/16 away from the back of the blade and the other was 3/16. : After I adjusted them the same I have'nt broken a blade since.
I did appoligize to my blade man and paid for the blades that he gave me, all is well.
EZ

[Tobacco Plug]

Howdy,
I know you said you put new B-57 belts on, but you may want to go ahead and check the blade screw in the top center of the C-frame.  It is supposed to be 1/16" below the bottom of the blade.  While new belts should have corrected the problem, I wouldn't rule this possibility out.  Good luck on one of the mysteries of sawing life. ;)

[steveo_1]

Steve,I am kinda new to sawmilling but when i broke a blade a few weeks back i took the blade wheel covers off to change it and noticed that the blade stretched and i kept tensioning it til it came out and hit the cover on the side ,it must have been heating badly to stretch that much or my inexperience??? to keep tightening the blade,but it broke right at the weld.I havent put so much tension on the blade after that, but also think i might be using a blade that is too big,becuase it was fairly new.Hope you get it fixed!

[ronwood]

Steve,

You might want to give Woodmizer a call also. They may have some other thoughts of what it might be. I have had my mill for about a year and broke my first blade with only one sharpnening. The band did not break at the weld. I made the adjustment that Lewis_Lawrence mention in his post.  Have not had any problems since.

Ron

[cut2size]

Thre are two bearings in the idle side wheel that sometimes need replaced.  Twice I have had the problem of blades breaking rapidly and unexpectedly with some regularity.  I even had blades break when the saw was not in the log.  Both times I replaced the idle side wheel bearings and the problem stopped.  It must have something to do with a harmonic vibration that begins when the bearings are about to fail.  That is just a guess, but the problem has been corrected with the replacement.  
Hope this helps,
David

[Steve_M]

Thanks everyone for all the thoughtfull replies.

Norm--I have been starting with about 2300#, it seems to want to fall back off to 1800-2000# after a few cuts(light buildup can usually be seen on top of blade).  If I adjust tension back up I can't keep it there.  The only time I have been able to maintain tension from start to break(300bf) is when I ran the lube wide open. Everything looks ok when I move the blade by hand/with tension.

Minnesota--I have between an 1/8 and 1/16 spacing between back of blade and roller flange.  I do however have a very shallow grove on the idle side roller where a blade has ridden without the roller turning ( this was present before I started having trouble).

Feltz--Saw only has a couple hundred houres on it and it is run inside.  I have only ran Woodmixer blades.

LL- I checked the top screw when I put the new B-57's on, it was ok.

My thought as I sit here is that I may have to much deflection in one or both of the guides, I will check that as soon as I get a chance.  I may just start over and go through the complete alignment procedure.  

Thanks again.

Steve

[iain]

the fact that you can cure the noise by flooding with lube tell's you that the problem is at the quides

 check for alignment from scratch as the book says
 not just a quick look

 the blade is fluttering as it goes past the rollers and the water is absorbing some of the high pitch sound (put your ear/skull against the frame for a differant world of sound)

its aslo filling the gap and damping down the impact split second though it lasts at each flutter

[BBTom]

I agree with min_boy and EZ that the most likely problem is the guide rollers being too far back, but your heat buildup suggests that they may also be out of alignment with the back of the blade and are "dragging" back on the blade as it runs on them.  It would take a serious amount of deflection to cause heat buildup. Rollers do wear and sometimes wear into a slight cone shape,  but not likely with only a couple hundred hours on the machine. Make certain that the bearings in the rollers are running smooth. A bad bearing could cause heat and problems. Good luck finding it!

[chevymetal]

Steve,

If your blades are breaking due to the back flange on your guides rubbing the back of your blade they will almost always have small cracks all the way around the back of the blade.  Try to keep 1/8" from flange to blade.

I know this can be a frustrating thing.  Here are a few suggestions that have helped me over the years:
1.  Blade tension around 1800#. Once you exceed 2000 cutting speed is increased but blade life is compensated.  2300# sounds awfully high to me.

2. Flat spots on a roller guide, or cone shaped guides all contribute to premature blade life. Along with locked bearings inside the guide (which will heat a blade up in a hurry).

3. No more than a 1/4" of roller guide downpressure should be applied to the blade.  I have found as little as an 1/8" has worked well for me.

4.  Belt insert wheels do work, but they can be abusive to blades.  If a wheel is out of round more than about .015-.018 this will certainly cause extra fatigue to a blade.  You have to consider two wheels both out of round 'hitting' the blade at two points of contact at every full revolution can be very damaging.  BTW this is what contributes to most peoples mill shake if they have out of round wheels.
I have seen belt insert wheels be out of round by as much as .050 and it was a blade eating machine.

Anyway I hope that helps.  ;)

[Kirk_Allen]

Welcome to the Forum Chevy!

Hope to see you post some more sperience ;D

Thats what makes this place so great.

Kirk

[gmmills]

Steve,
   From reading your post I see your logs are well seasoned. We all agree your problem is the blade heating up and your blade tension continues to drop as the blade continues to heat.
   If your mill and blade guides are aligned, here is something you need to consider. THE BLADE!  If your 10/30 blades are set at factory specs 0.23 there is too much set for those dry hard logs. In these type of logs,I use 9/29's set down to 0.17.
   I'll bet you have alot of sawdust left on boards and cant. If this is true, your blade heating problems are caused by the sawdust. With 0.23 set the blade is making more sawdust than the gullet can carry out of the cut and spill over the sides of the blade. The excess dust is causing friction in the cut and heating the blade up.
   I generally saw nothing but hardwoods and 9/29's are all I use.I run sets from 0.15 to 0.19.Out of the box, 10/30's are too agressive for me.

  Hope this helps...
         Mike

[Swede]

Once I broke a blade! Not remember why but think I forgotten to lift the saw unit before moving it back "home"  It was at my first sawig job where I went never sawing a log before. (The "Swede way" to do things)

Sawing a big oak the band guide hit a knot. Tryed to go back a little and the blade ran off the wheels. Using a Suffolk Chisel Steel/ Håkanssons band I only had to bend it straight by hand and put it back to the wheels. Two boards later you couldn´s see that band ever been crooked like an accordion bellows.

I tension the band just so I can play a clear tone at the upper part.

"Swede Lubricate" is 50% oil and 50% diesel fuel.

Using a dull band I once get some smoke from the kerf but never felt the band or anything else hot and never got a burned surface at a board but a layer sawdust left there.
It´s dagerous to take the sawdust in the hand (if the band breakes just then.........) but when I do, the sawust always is warm as my hand.

Yes, "Amerika-Sågen" is a 4-poster but I don´t think it have any importance. ???

Swede. *still without smiley-buttons and prevew funktion* :(

[woodmills1]

If you haven't found the problem yet I would say make sure to recheck that center top screw.  It might be that it looked good when the belts were installed but as the force of the blade tension caused them to set in the pullies it is now off.  When you bought the B57 did you get top quality Gates(or equivalent)  My only blade breaking repeats were when the top screw was out of adjustment.

[C_Miller]

I had problems with the bandwheels being worn and the B57 belts not keeping the blade off the wheel. there has to be a little clearance clarence.

C ;)

[Steve_M]

Should have done this a long time ago, but I wanted to bring this back up and thank everyone for there help and advice.  As it turnes out I think BBTom had it nailed 8)---I had a bad bearing  in the moveable guide roller.  I couldn't detect it untill I removed the roller and tried to spin each bearing with my finger.  The bad on would spin but not freely.

Original rollers were greasable and I may have over greased and pushed the seal out and allowed dirt in.  Ordered two new roller guides from WM (new ones are sealed-no zerts) and have not broke a blade since 8).

I think the blades I broke cost me a lot more than the new rollers  It does usually cost a little to get a good education.

Thanks again

Steve

[leweee]

Steve_M thanks for the update. ;D You are now a graduate of the school of  Hardknocks.... at  this school you always get the test before the lesson. Ain't  education fun :P 8) 8) 8)  leweee