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I suppose there are two alternatives for the death of a bandsaw blade:
I have never experienced scenario #2 but I've broken a few blades on my bandsaw. Is this the normal way for them to go?
Does breaking a bandsaw blade indicate something such as too much/too little tension?
Blades fatigue over time because of the bending around the tires. They will eventually break due to this. Always inspect blades for stress cracks which usually appear in the gullets, before welding. If a blade is found to have stress cracks, then its time for a new one.
I sold saw blades for a living to manufacturers, so I know a little. If used absolutely correctly, the blade should wear out (dull) and not break. In the Real World, we seldom see any absolutes.
RE repairing (welding) blades; I've seen quite a few (industrial-size) bandsaws which had welders built right in; break a blade, count your fingers, trim the ends and weld them without removing the blade.
There are always compromises to be made to have a general, all-around BS blade. Seldom is a wood cutting blade useable on metal, although metal-cutting blades can cut wood without too many problems. But unless you're in a production environment (cutting the same thing, mechanically fed, changed before too dull or else they overheat & break) you have to get the finest TPI, pitch, and set you can stand to use on the biggest thing you'll cut (sort of prepare-for-the-worst situation).
Does breaking a bandsaw blade indicate something such as too much/too little tension?
It can but it could simply be from material fatigue or a poor weld.
So anyway, blades break or go dull, what then?
This is the interesting question for me since in the past worn bandsaw blades were routinely re-sharpened but like a lot of similar changes over time this is seen much less frequently today. Many woodworkers aren't even aware resharpening is a possibility. And even breaks are repairable (and easily, the work takes just minutes in the hands of someone who knows what they're doing).
Part of the reason for this type of thing is the lower cost of 'consumables' which makes repair "not economically viable" as they say in the industry. But doing maintenance or repair yourself sidesteps that reality.
However, since a lot of woodworkers don't have welding equipment or the experience to re-weld a critical area like this you are still left with a broken blade, but that doesn't mean it has reached the end of its life and should go straight for recycling.
A common use for broken bandsaw blades in the past was as stock for bowsaw blades and this is still perfectly viable. And making the bowsaw frame is a great woodshop project in itself.
That is just the tip of the recycling iceberg. Other potential uses include:
Just one broken blade could provide nearly a lifetime's worth of any of the above.
Good question. Every bandsaw blade I've gotten rid of has also been because it broke.
While this can be an indication that there is incorrect tension on the blade, it also just happens from use. If it snaps pretty early, likely the tension was wrong or you did something dumb. (I broke one because I turned a piece to sharply). Wider blades are more likely to get dull before snapping, and some of them can be respharpened, though for most band saws it is likely cheaper to buy a new one. Some high quality blades can certainly be worth the sharpening.
Yes, the teeth become dull. In my youth, there were shops that would take your blades and resharpen bandsaw blades and table saw blades for a small fee. Too much tension, or too much lateral movement can cause problems in my experience. Back in the day, sometimes the new blade would break at the weld, but I have not see this in a long while. (If you cut wood then metal and then wood again with the same blade, it is easy to 'feel' the difference due to the duller blade.)
Also see http://www.bandsawblade.com/chart.htm
Dulling may be symptom of other tuning issues. http://vermontamerican.com/article/ultimate-guide-band-saw-blades-break-troubleshooting/
My rule of thumb (still got both of mine, knock on wood) is... when the blade gets rewelded about the fourth time, it's probably not going to get welded again; by that time, the back has grown too brittle and it's probably lost some teeth. Until that point, reweld & resharpen.
I've never had a blade breakage that I could trace back to overtensioning, although I'm always just a bit tender with tensioning anyway - my first bandsaw had a honeycombed cast-aluminum body, and "proper" tension was spooky with it - it felt like the saw's body might give way at any time. That was an illusion, of course, but it taught me not to overtension. Lots of bandsaw blades (TimberWolf springs to mind) want very little tension - only enough to prevent the blade from fluttering.
