Common reasons for band saw blades to break?

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rjwolfe3

rjwolfe3

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I was cutting, believe it or not, Styrofoam with my band saw and the blade snapped. (Dove for cover and then had to change my shorts:eek:) There was no metal or foreign material in the foam. No damage to the teeth of the blade. 3/4" blade for resawing lumber. I did notice a slight wobble before it snapped. The blade was tensioned correctly. I rarely use the band saw maybe once every 2-3 weeks and I always release the tension when done. The saw is a Grizzly G0555 with the extension and it's not even a year old yet. The blade came from a local saw and tool shop. Any ideas as to why the blade snapped and what I can do to prevent it in the future?:confused:
 
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The blade is welded together and just gave up.Same thing happen to me yesterday ihad cut sereral hundred gator blank's with it.Just turn it on and before it reached rpm snap.No need to run it is all over as soon as it break's.But i still had to make sure i did'nt have any missing part's.
 
Just checked, not at the weld. Would have made for a simple answer. BTW the blade is maybe 8 months old, if that. And I really haven't really cut much with it.
 
Here's a link to a site that has loads of info on bandsaw blades, though I think it is meant primarily for metal bandsaws.

I've often wondered about releasing the blade tension when not in use and have never found a definitive answer. Maybe the constant tensioning/releasing adds to the fatigue, I really don't know:confused:
I only have a cheapy bandsaw and even cheaper blades so I don't really worry when they break.

http://www.bandsawblade.com/help.htm#term
 
Well I thinking of upgrading to one of those $100 blades but not if there is a chance of it snapping after 6 months of use. This is the first problem I have ever had with the band saw.
 
Typically a blade will break when it is flexed back and forth causeing an edge crack followed by catastrophac failure.

I would guess that the Styrofoam was simply what you were cutting at the time and that prior materials weakened the blade to sufficiently cause the failure when put under tension.

From what I know this could be cause by misalignment/vibration or heat from dullness.

You cut anything challanging lately? Hard woods or metal?
 
the bandsaw book reccomends releasing tension after use.

Band Saw Use Tip #7: It is advised that you take the tension off of your band saw blades every time you wrap up work for the day. Few follow through, though it would certainly increase the life of the blades and the tires if we did. It's easier to do this if you have a quick-release tension lever on your band saw.

Some random web site

http://www.associatedcontent.com/article/2042957/10_tips_for_using_a_band_saw.html?cat=6
 
One thing to look at is if there are any small cracks on the blade body (possibly near the break but could be other places also). It is possible that the blade is rubbing somewhere and that will create heat which will "work harden" the metal body of the blade. Overtension may make this worse. Riding hard on the thrust bearing will also do it. Side guides that are buggered up and rubbing the blade, build up of junk on the wheel tires...
 
Manny said:
the bandsaw book reccomends releasing tension after use.

Band Saw Use Tip #7: It is advised that you take the tension off of your band saw blades every time you wrap up work for the day. Few follow through, though it would certainly increase the life of the blades and the tires if we did. It's easier to do this if you have a quick-release tension lever on your band saw.
Click to expand...

I've also seen that, Manny .. but I've never seen any information to back
it up. I've mostly seen it claimed by people who either make or sell the
quick-release bandsaw tension levers.

That doesn't mean it isn't true, I've just never seen any data to support it.
And some old timers tell me it's hogwash.

It SEEMS logical .. until you think about it. Steel under tension snaps after
a certain amount of time? makes me wonder about riding in elevators.. or
driving over a suspension bridge.. or all those steel banded boxes sitting
in a warehouse for years. Do I really want to walk near those? Should they
have an expiration date on them? :tongue:
 
Haven't you ever walked past a steel-banded skid and, all of a sudden, POP!!!!

The band BROKE!!!!

Actually, neither have I.
 
Being a self proclaimed tool snob :) , I only buy quality Lennox blades and have never had one snap on my bandsaw and I use it a LOT in strenuous situations. That said, I have had a big 1 1'4" blade break on my sawmill and it was a little spooky.

I would suggest that you consider buying the best blades you can afford. They do seem to make a difference.
 
I have a band saw that I bought in 1974, I have never released the tension on the blades. The only time the tension knob is turned is to take a blade off and to put another one on it. I have heard of releasing the tension but nobody seems to be able to give me an answer as to why it should be.
 
I also think that releasing the tension helps the blades any is hogwash. but the tires are another matter. it does help to not have that pressure compressing the tires while just setting idol. Still I personally do not release tension on my blade. a band saw has enough reasons to be moody already. Rob, my bet is it was jsut a weak spot in the blade for one reason or another and it finally lost the fight. Better quality blades are a good idea. maybe not $100 worth of quality. I have a place locally that sells good quality blades at good prices. It does help. I would go for a carbide tipped blade if I was sure I would not want to cut iffy wood on my saw. Iffy wood is any recycled, been laying around where it can get dirty etc. mainly nothing that might have a rock or nail in it. I still seem to see far to much of that going through my shop but I am getting better.
 
I have 4 bandsaws and I only release the tension on my bandsaw mill and this is because I ruined a pair of tires by not releasing the tension, I have not had any problem with the other saws, I also weld my own blades, I use a electric welder and I silver dolder my blades, I find that the electric welded blades seem to brake (on the weld) more than the silver soldered blades. Aloha.

Chris
 
I can see where releasing tension on the blade would help the tires, but how much tension would it take to induce metal fatigue, and would releasing the tension be that beneficial to the blade it's self?
 
Have a G0555 without riser kit. Best blade for work I do is 3/8" with 3 TPI .025 thickness. I use Lenox flex back (carbon steel) blades and happywith results.

Think your problem may be width and or blade thickness. While specs say can run ¾" blade on this saw, think that is a tad optimistic. If you drop, back down to ½" blade will see better results.

Sweet spot for G0555 is either ½" or 3/8" blade. You need proper TPI on blade for type cutting you're doing. Blade thickness very important, never want to exceed .025 or .032 thickness.

Good luck!
 
I had this happen to me once. I managed to have a small sliver of wood drop below the table and wedge between the wheel and the band. This puts so much strain on the blade it snapped!

Could styrofoam beads have gotten between the wheel and blade in your case too?

I don't have a solution to this, but I am careful now not to let small pieces fall into the saw slot.
 
rjwolfe3 said:
Well I thinking of upgrading to one of those $100 blades but not if there is a chance of it snapping after 6 months of use. This is the first problem I have ever had with the band saw.
Click to expand...


It sounds like you have had a case of just metal fatigue. I bet if you looked under a strong magnifier you would see little cracks.

DO NOT GO TO 100 DOLLAR BLADES.
I did that and its not worth it. I run my band saw daily as you might guess as I am a wood dealer and turner. I have found a place that was recomended here on IAP that has great blades for little money. That is all I have used for the last two years and I have never had a break again.
The name of the place is www.Woodcraftbands.com
I have found that these blades stay very sharp for a long time. It cost me less to use these blades than to play the games with the expensive ones and have to send them back and forth to be sharpened. I also do not do the tension thing as I use my saw all the time.

Any questions please ask.
 
For those that don't release the tension you are rolling the dice. The reason a blade is released is not for the tension of the blade but the indentation it leaves in the tires and also the strain on the bearings and wheels. Now if you use the bandsaw quite regularly you will not notice these things but if you use it sparingly you are asking for trouble.

Now as far as blade snapping can be caused by many things. I too buy Lennox blades but I have snaped a few. Here is a couple reason a blade will snap. Blade fatigue which you may or may not be able to see and have no way to know when this will happen. When a blade is runnning and cutting it is actually expanding and if you are doing curves and such you are stressing it at this heat level. When the blade is idle it will cool and shrink, thus adding to blade fatigue. Dull blade and you are pushing it to its limits ( always a good one) Misaligned wheels or bad bearings. If you get a hump or grinding noise you are not only taking life out of the blade but also the saw. Poor alignment of the guide bushing and or thrust bearings. If you are throwing the blade off its natural course that is taking life away and adding stress to the blade. I have snapped a lennox 3/4" carbide tooth blade cutting exotic woods. It seems the wood had too much silica in it and caught the grain just right and the tooth got hung up on it and snapped. It happens and you move on but learn from these things. So there are many things that can cause a blade to snap. Use good quality blades and keep them sharp.


Just one other note, yes a $100 carbide blade is worth every penny especially if you do alot of resawing as I do. Try resawing 12" exotic boards (even white oak or ash) with an ordinary blade and see how many you get done. Been there done that.
 
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Yes I guess I should have chose my words better and say this is my opinion and what I have found to work for me. Good luck and have a great day.
 
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