Bandsaw blade breakage

[Paul Williams]

A little over a year ago I upgraded my bandsaw to a Laguna BX 14. In that year I have broken 4 blades. All of them at the weld. My old saw might have broken 3 or 4 blades in the 20 years that I had it.

My first question is if it is normal to break at the weld?

My second is what might I be doing wrong, or what I should check on the saw?

The 4 blades came from 3 manufacturers. Two were Timberwolf blades. One was tightened to the scale reading, the other by the wobble method. The one that broke last night was a 1/2 inch 3 tpi Laguna blade. The third manufacture was Starrett. I see no difference in how the blades broke.

Any suggestions would be appreciated.

[Karl Loeblein]

Just a few suggestions to try:





Smaller wheels flex the blades more. Make sure your blades aren't too thick (0.025 vs 0.032) for your wheel size.
Apply some paste wax or cooking spray on blade to lower friction.
Check welds to make sure they're ground smooth with nothing to catch on the guides. I use a small air powered grinding wheel after silver soldering my blades together.
If blades aren't bent when the weld breaks then learn how to silver solder blades so you can reuse them. May not be worth your time on cheap blades.
Make sure the back blades guides are set as close as possible to the blade without touching to keep the blade from flexing front to back.

[david privett]

may not have properly heat treated in welded area to relieve hardness of weld and blade letting it flex easier.

[Paul Saffold]

I have the Laguna 14-12 which may be similar to your Laguna. I broke 2 blades in the first few months. Both were Lenox Diemaster 2 and broke in a gullet, not at the weld.

The tension scale in the 14-12 is like a refrigerator magnet. It can slide around. It probably moved in transit on my saw.

You will be much better off if you follow the instructions in the manual for setting the tension. After you get the tension adjusted, move the tension scale to match the width of the blade you are using. If you change to a different blade I would not trust the scale and would check the tension according to the manual.

This is one of the few things I dislike about the saw. Over all I have been very happy with it.

[John K Jordan]

Paul, I agree with others - make sure the tension is right. Rather than guess, I bought a bandsaw blade tension gauge. These can be expensive but John TenEyck provided good instructions so anyone can make one in a few minutes. This might at least eliminate one variable from your search.

http://www.sawmillcreek.org/showthread.php?250388-Bandsaw-blade-tension&p=2640833#post2640833

His post describes how to do the test and exactly how to do the simple math. All that is needed is a caliper and some small clamps. Calculator optional.

400674

JKJ

[Reed Gray]

If they are breaking at the weld, that, to me is a bad weld job. I don't think I have ever had that happen. I have broken a number of them in the gullets. This can be caused by having the blade guide too high, which causes the blade to flex, and they start to break on the back side of the blade. Most of the time there will be a number of breaks along the blade and they are junk. The blade will start to oscillate front to back before this happens. It does give you an adrenaline rush when a 1 1/4 inch blade breaks.... Also, breakage can be caused by pushing too hard, and not having the thrust bearings (both top and bottom) not set properly. Pretty easy to tell if the top thrust bearing is off, but since the bottom one is under the table. This also starts cracks on the back side of the blade. If the blades break at the weld, they may be salvageable. If you have a local saw shop that fabricates blades, they could tell you. I am lucky to have a very good shop here in town.

As for tension on the blades, I just crank it up, which is what the lead guy at my saw shop said to do. Most of the tension meters are way off. He told me on the little one to crank it up to the '1 inch wide' blade setting. On my Laguna 16HD, they just have numbers, and I go up to almost the top setting. The good tension meters cost a couple hundred dollars...

robo hippy

[Jack Tyree]

I bought a Laguna 14-12 several years ago and got the carbide tipped $150 blade. It work wonderfully for resawimg thin veneers. Tracked straight and cut a very smooth surface. But Ileft the blade under too much tension for too long and the blade broke at the weld. Sent it back to Laguna and they rewelded it for $45. I didn't let it set under tension when not in use. It broke at the weld the second or third time I used it.
I told you that to tell you this: DO NOT trust the tension guage. Do not leave tension on the blade when not in use. Since then I have not had a problem.
Here's another tip. When you first install a new blade set it to track so that the gullets are at the very crown of the top wheel, dead in the center of the wheel. The saw will not drift at all.
The very best band saw video on YouTube is this one: https://youtu.be/wGbZqWac0jU.
I recommend it to anyone having trouble with their saw. Alex explains absolutely everything you need to know about setting up your saw in an easy to understand format.

[Paul Williams]

Thanks everyone for the replies. I have emailed Laguna, but not received a response yet. I have everything to make either of the DIY tension gages that John linked to, and think I will make one just out of curiosity. I will let you know if I learn anything interesting about the saw's tension gage accuracy.

[Reed Gray]

I never take the tension off of my blades, including the 1 1/4 inch blade on my Laguna 16HD. They have never broken at the weld. For that blade to break at the weld, says to me that it was a bad weld, not the tension. Laguna owes you some money.

robo hippy

[George Guadiane]

Jack said: "DO NOT trust the tension gauge."
DO NOT trust the tension gauge. I got that from the head tech at Laguna who deals with the ResawKing blades. I hve a Laguna 14/12 and was on my second broken blade (in the gullet) when I mentioned using the gauge. He said NEVER use it. Well, maybe for a refrigerator magnet. Use the finger pressure test.
After that, I've had no problems.

[Paul Williams]

I agree, "do not use the tension gage." but I am still going to check it to see how far off it really is. I have trouble believing that I can really break a 1/2 inch blade with over tension and not feel that I am really working to put that much tension on the blade. Also one of the Timberwolf blades that broke had very little tension on it. The other had tension based on the gage. Both broke at the weld. Something strange is going on and I am likely to keep playing with things until I understand what is happening that breaks welds.

[John K Jordan]

Did you check the guides too, upper and lower? Rear "thrust" guides should not touch the blade until you are pushing wood into the blade or it can put stresses on the blade.

I "stone" a new blade as per Duginske (I think) - hold a small knife-sharpening stone against the back of a blade while running to smooth and slightly round the sharp corners.

I have had only one broken blade in as long as I can remember and I think it was defective, it didn't break at the weld. Scared the fool out of me. I mostly use 1/2" 3tpi or 4tpi blades made cut and welded locally.

JKJ


I agree, "do not use the tension gage." but I am still going to check it to see how far off it really is. I have trouble believing that I can really break a 1/2 inch blade with over tension and not feel that I am really working to put that much tension on the blade. Also one of the Timberwolf blades that broke had very little tension on it. The other had tension based on the gage. Both broke at the weld. Something strange is going on and I am likely to keep playing with things until I understand what is happening that breaks welds.

[Bill Boehme]

A few random thoughts:



Blades get dull and that leads to forcing the wood into the blade. The blade should cut effortlessly through the wood.




Using the wrong blade ... cutting a thick piece of wood with a blade that has small gullets causes heating and binding.




Guides not set correctly or tracking not adjusted correctly.




Tension too high. Detension the blade when not in use.




Don't use the built in gauge ... it's just a trinket.

[Richard Coers]

Something is really off. Maybe a video or two of you and the saw in action might help someone recognize the problem.