Bandsaw Blade broke

[Herr Dalbergia]

Hello,

After having some issues with my Resaw King, I went back to the Woodmaster CT. Took a fresh, brand new blade out of the box on friday afternoon. Put it on my saw, adjusted everything and started resawing the sides for my current BRW resawing project. Everything worked perfect, I resawed about 50 side sets, working friday evening, the complete saturday and this sunday morning.

What better than resawing some BRW on a sunny sunday morning....I had one billet still left over for resawing, so I started this morning. The blade was still working perfect, the cut flawless, no drifting, no strange noises, the surface quality very nice, no wobbling. Al systems go.

I had just done the last cut for the last side of BRW, really the very last side had just came off the saw, I took it and turned around for putting it away on the stash, also having a small fast look at it. I did not turn off the saw immediately, but luckily I was away from the saw, only 3 or 4 feet, but at least not next to it.

Suddenly out of nothing there was a big bang http://www.luthiersforum.com/forum/images/smilies/wow7-eyes.gif and actually I realized quite fast what probably had happened and - just run outside of the room around the corner.

For a sunday morning this was quite exciting...

What do you think? Me and my brother have the same opinion, since the blade broke where it broke, we somehow assume there was a mistake in the blade or the weld, or during the welding.

This is also the very first Woodmaster CT which ever broke, and I am using the same tension on all of them. Tomorrow I will contact the company where I bought these baldes, I hope they will cooperate and send me a new blade.

Please have a look at the pictures in the link below, how do you judge the situation?

https://picasaweb.google.com/115793185519493121307/WoodmasterCTBandriBladeBreakage

Cheers, Alex

[joe maday]

because it is so close to the weld...could the heat from the welding when the blade was made....harden that area??...then over time bending around the diameter of the tires, cause it to fail?

[Erik Loza]

Was the wood green or was it dry?

Erik Loza
Minimax USA

[Joe Kaufman]

I was trimming acrylic pen blanks to length when a 1/8 inch thick cutoff ended up between the blade and tire. Looking back, it is surprising how long you can get away with some thing before the expensive reminder. I don't trim pen blanks with the band saw anymore. Any chance a small piece of scrap got caught in your case.

If what appears to be a brown discoloration is actually on the surface of the fracture, it could be indicative of a preexisting fracture. Good idea to contact the mfg.

[Al Launier]

In the 4th & 5th pictures there appears to be something unusual in the cross-section of the blade. When looking at it, it appears to be an "inclusion" in the metal. If so, then I would guess it failed from fatigue in this area. Can you look more closely through a magnifying glass? Doe it look like there may have been some missing material, or perhaps foreign material within the blade when it was molten, before making it into metal bands?

[Shawn Pixley]

I am with Al here it looks like there is a slag inclusion or porosity at the break. You obviously ran a lot of stock through the saw. If BRW is Brazilian Rosewood in your post, then the blade has done its duty. I am not convinced they owe you a new blade. If I interpret your comment to mean you cut fifty sets of five inch by four foot sides for a guitar, then the carbide had likely dulled enough that you compensated by pushing harder. The steel band is not going to hold up indefinately.

[Herr Dalbergia]

@Mr. Loza: the wood was dry, abot 60 years old.

@Mr.Launier and Mr.Pixley:

Yes, I also think so, you have very good eyes btw ;). For me it looks also like there is something IN the blade, actuallly it looks like there is rust IN the blade.
Later the day I will call the manufacturer, lets see what his opinion is.
BTW, Yes, BRW is Brazilian Rosewood and I am cutting guitar sets, BUT for a Woodmaster CT 50 side sets is nothing, I am using the Woodmaster CT since about 2 years, and all the others have done way more wood before they got dull. Also this blade was still cutting like butter, like new, and my feedpressure was still very low.

Thank you for your comments, Alex

[Jim Matthews]

What does a blade like this cost?

[Herr Dalbergia]

I payed 650 Euro for 5 blades.

[Tai Fu]

Sometimes it's down to the welder too, if they're having a bad day or whatever. Maybe you can tell them about it and see what they think. If it's their fault I am sure they will replace it.

I quit using Woodmaster CT because I find I don't really move that much wood (I doubt my bandsaw could handle that kind of volume, I'd like to have a 26" if I am moving that kind of volume) so I switched to steel blade of the same pitch as the Woodmaster CT. It has a slightly thinner backing (.032 rather than .035) so less worry about breakage but it can be resharpened cheaply when dull. So far I have not needed to resharpen them.

Someone said that the problem with carbide blade is that you can't really tell the blade is dull (I think the feed pressure just increases) so people would force it in anyways causing the blade to break, but that's usually not at the weld. In fact I was initially going to get carbide blade from him but he recommended against it because he showed me one that was broken and rewelded in several places... obviously if it did that no amount of rewelding is going to fix it. He said that the carbide blade might last twice as long before dulling rather than 10x like manufacturers claimed.

[Erik Loza]

Just observations I have made about carbide blades over the years (and I probably have as much personal experience and owner feedback as anyone...).

1.) Carbides are very sensitive to feed rate and pressure, due to their flat kerf. They don't clear stock as quickly as a skip-tooth blade, so as the user, you need to be aware of this. Sometimes, I hear, "Oh, it's carbide. I can just power through the cut", and that often fatigues the teeth prematurely.

2.) Because the backing material is so rigid, they may snap under conditions where a more ductile steel blade could stetch and accomodate higher feed pressure.

3.) Green wood will dull them very quickly. I suspect what happens is that there is a lot of heat buildup in the gullets, where the wet sawdust accumulates, and that actually heat-fatigues the blade.

4.) You can get a blade with bad welds from anyone. ANYONE. Have forgotten the number of times an owner will call me and swear up and down that their machine is at fault and sure enough, it's the blade or blades.

Just my 2-cents as always,

Erik Loza
Minimax USA

[Gus Dundon]

Band saw blades don't last long. Though carbide blades last 10x longer than any other blade ,it won't staysharp forever. If you used a dull blade for cutting, I could conclude that its dullness caused the breakage.As what have said, it's hard to tell if carbide blade is dull. However you said that it still cuts like a butter, so, the other two reasons I could think of are bad band stock and feed rate.

[Steve Menendez]

The proximity of that break to the weld seam strongly suggests a problem with the welding process. Often, if the alignment at the weld seam isn't correct (negative camber for example), a fracture like this will be the result. Sometimes a blade with improper alignment across the weld seam will make a rhythmic noise as the weld seam passes through the saw's guides.It's also possible that there was a stress riser left over from the jaws installed in the welder at the time your blade was welded. Typical band saw blade welders can operate with thousands of pounds of clamping force. If there is a bit of grit, slag, or whatever stuck between the welder jaws and the blade, an indention will be made in the blade which will serve as a stress riser and a source for future failure.Often, if there is anything stuck on a welder's jaws, it will show up as "snake eyes" on the finished band. That is, there will be a second indentation located between 1/8" to 1/4" away from the first indention. This is due to the way welder jaws are re-positioned for welding and tempering of the weld seam and heat affected zone.If that were my blade, I would definitely submit a claim to the people who welded the blade, asking for a replacement or credit.Steve.

[Willem Martins]

What is the blade width and the blade thickness?

What is the diameter of your bandsaw wheels?

The reason I am asking is that blade would fail pretty fast in fatigue on my 17" Grizzly as the wheels are too small in diameter and that blade is too wide and thick.

[Erik Loza]

FYI that I have sent out probably hundreds or Tri-masters and Woodmaster CT's for 16" saws over the years and never had a failure occur due to the diameter of the flywheel. Whether or not this or that 16" or 17" machine can tension either of those blades enough to get it to cut straight is often a different story.

Erik Loza
Minimax USA

[Herr Dalbergia]

Hello,

actually the situation is like this:

I bought 5 Woodmaster CT, and used 4 of them with cutting quite a lot of wood. I would say I have some experience how much a CT can cut, and when it is dull, what feedpressure is ok. The CT last more than 10 times compared with a for example Hema Ikarus, what is also a good blade. But the CT just last so much longer.

At least the first 4 I used.

The 5th broke after perhaps 3 hours of sawing. The others lasted perhaps something like 30 or 60 hours...so there is something wrong....in my opinion.

The blade is 0,9mm thick, my wheels have a diameter of 70cm. This is not a perfect 1/1000 combination, but it should be ok, and again, it worked with the other 4 blades without any problems.

The blade was stored in its original packing in a warm, dry, room.

Till now, it seems that neither the dealer who welded the blade, nor the European distributor of the raw band coils feel responsible, or a showing any sign to help me.

Why am I not surprised....

Cheers, Alex

P.S. does anybody have an Emailadress from Lenox in the USA. I want to write them directly if they are willing to guide me.

Thank you!

[Tai Fu]

I do find reputable US suppliers to be rather helpful with customer services... elsewhere I am not so sure. It may have to do with competition too. Sometimes I get tonewood from European suppliers and they are defective (badly bowed or whatnot) and they don't seem to think they are responsible.

[Larry Frank]

I looked at the picture of the fracture surface. The dark area is not slag or inclusion. It appears to be a crack that was there for sometime and discolored. It is not unusual to see this in a fracture surface. It appears to be a pre-existing crack. During sawing, it is likely that the area fatigued, the crack grew larger and eventually broke.

Without a full metallurgical investigation, it is not possible to determine exactly. Such an investigation should include a very good examination of the fracture surface ( hopefully with a scanning electron microscope), testing of the material near the weld and going away from it and a few other things. I think the bottom line is that there was a defect (the discolored area) in the blade when you got it and caused it to break prematurely.

[Myk Rian]

The 5th broke after perhaps 3 hours of sawing. The others lasted perhaps something like 30 or 60 hours...so there is something wrong....in my opinion.
This tidbit would have been nice to know right from the start.
My guess is a bad blade.

[Jim Matthews]

I had no idea these were so expensive.

http://www.lenoxtools.com/Pages/ContactUs.aspx

[Tai Fu]

He got 5 of them, and for 133" length it already costs me about 120 dollars, more if it's for a bigger saw. So 5 of them at 650 euros is still pretty good

[Steve Menendez]

Here's a list of contacts for Lenox (American Saw)....

http://www.lenoxtools.com/Pages/ContactUs.aspx

Have you tried any of the European blades (Munkfors Sagar / Hakkanson) (sp?). They do not have a large presence in the USA, but it's my understanding that they are popular in Europe.

Steve.

[Willem Martins]

FYI that I have sent out probably hundreds or Tri-masters and Woodmaster CT's for 16" saws over the years and never had a failure occur due to the diameter of the flywheel. Whether or not this or that 16" or 17" machine can tension either of those blades enough to get it to cut straight is often a different story.

Erik Loza
Minimax USA

Erik,

For what it is worth, see the link below for recommended blade thickness and wheel diameter. The suggestion is not to go beyond 0.025" for a 17" Grizz with a 16 3/4" dia wheel.

I have broken two Tri-Masters 0.032", re-sawing with excellent results, normal tension, but too expensive to keep on doing this. Upon failure, there was a fatigue crack failure, but further examination showed a number of small fatigue cracks starting in several places on each blade.

I now resaw using a 1/2" Bi-Metal 0,025" blade, with reasonable results. I do a lot of veneer resawing 1/16" x 12" BTW. It could be that your customers are not heavy duty users?

http://www.kmstools.com/blog/choosing-bandsaw-blades/

Everything I veneer, I resaw. The yellow wood in this project is all 1/16" re-sawed veneer.

http://www.sawmillcreek.org/showthread.php?216833-Neoclassical-side-tables&highlight=

[Steve Menendez]

William:

Your post about bending radius (around the bandsaw's wheels) is something that a lot of people overlook, but it's extremely valuable information. There is much more tension put on the outside edge of a bandsaw blade as a result of bending around the saw's wheel than there is from the linear tension alone. Obviously, the two stresses are related to one another, but the stress associated with bending around the wheel increases exponentially with thickness of the blade.

With respect to your resawing, I'm curious to know if you have any experience with the purpose made resawing blades offered by some of the vendors? I'm thinking of Highland Woodworking's Woodslicer blade, or the X-Tra Edge blade offered by www.Sawbladeexpress.com. Both of those blades are 1/2 x 0.022 variable pitch blades with low set values and shallow set angles.

Steve

[Tai Fu]

Yea according to that guide you need a 26" bandsaw to use a .035" blade but obviously people have used 1" Trimaster and Woodmaster CT on something much smaller. There was a time when 1" Trimasters would break on 18" wheels because of the steel they used but they have since refined the steel to work on 18" wheels.

[Erik Loza]

Willem, I can't disagree with your experiences except to say that I have sold hundreds (no exaggeration...) of Lenox Tri-Masters to MM16 owners over the years and never heard of one failing due to the diameter of the wheel being too small. One or two have snapped at the weld, which is a vendor's defect, not the blade's fault, but no cracking at the gullets. Now, I am talking about Italian saws which have flat tires and wheels. I've never tried to use a carbide on a saw that has crowned tires, so maybe that is an issue but if the wheel and tire are flat, a 16" saw isn't going to kill a carbide blade just due to wheel diameter. Wheel profile, maybe. But not diameter.

Just my personal experience.

Erik Loza
Minimax USA

[David Kumm]

For what it is worth, I've also found that running a blade hard against the back bearing shortens its life too. Can't say how much or how often but my blades last longer now that I tension enough to not spind the bearing. That tension also means the blade doesn't really touch the side supports either. Dave

[Duane Meadows]

I have has a Woodmaster CT on my Grizzly 16" for over a year. It has crowned wheels. No problems at all so far. The reason I went with the CT is although some of the special resaw blades cut well new, most dull quickly. the CT has outlasted several lesser blades.

David, I do have ceramic thrust bearings, not sure how much difference that makes, but they sure last longer. May never have to replace them!

[Willem Martins]

Willem, I can't disagree with your experiences except to say that I have sold hundreds (no exaggeration...) of Lenox Tri-Masters to MM16 owners over the years and never heard of one failing due to the diameter of the wheel being too small. One or two have snapped at the weld, which is a vendor's defect, not the blade's fault, but no cracking at the gullets. Now, I am talking about Italian saws which have flat tires and wheels. I've never tried to use a carbide on a saw that has crowned tires, so maybe that is an issue but if the wheel and tire are flat, a 16" saw isn't going to kill a carbide blade just due to wheel diameter. Wheel profile, maybe. But not diameter.

Just my personal experience.



Erik Loza
Minimax USA

Could be the crown?

I loved my Tri Masters. If they did not fail, would still be using them. If it were not for the costs, I would have tried a Tri-Master 1/2" x 0.025 3TPI Standard, but it gets pricey. I can't remember, but have tried a gazillion other blades as I do a lot of resawing. To get to 1/16" accurate 12" high, after the Tri-Master, the best results so far is with a Lenox Bi-Metal Diemaster2 blade, 1/2" x 0.025" Hook 4TPI. One has to just feed a bit slower, blade life is good and tracks really well.

The last I tried before the Lenox Bi-Metal was a Tiberwolf 3/4" x 0.025 and the feed was real slow. On Pau Amarello (Yellow Heart) veneer resaw, the blade was useless after the fourth re-saw cut.

[Gus Dundon]

Hello,


At least the first 4 I used.

The 5th broke after perhaps 3 hours of sawing. The others lasted perhaps something like 30 or 60 hours...so there is something wrong....in my opinion.


Thank you!

Premature blade breakage?

[Willem Martins]

I have has a Woodmaster CT on my Grizzly 16" for over a year. It has crowned wheels. No problems at all so far. The reason I went with the CT is although some of the special resaw blades cut well new, most dull quickly. the CT has outlasted several lesser blades.

David, I do have ceramic thrust bearings, not sure how much difference that makes, but they sure last longer. May never have to replace them!

With my experience, a thinner Bi-Metal blade will give about the same life, perhaps slightly shorter than the Carbide tipped. The difference is the Bi-Metal will be blunt, whereas the Carbide will fatigue crack on my smaller saw. My Tri-Masters took a while to fail, after quite a bit of re-sawing, but they will still be perfectly sharp when fatigue cracks start showing up. It gets expensive. Bi-metal = $40, Tri-Master = $180.

[Herr Dalbergia]

Ok....

so...the European Lenox branch office and the German responsible agent decided that I get a new blade for free, which was shipped from the workshop in Poland via the German distributor to me...

Not joking....Netherlands to Germany to Germany to Poland to Germany to me...not the blade itself, but just the decision.

Anyhow, I have a new blade, that's nice.