Broke a bandsaw Blade -but what cause?

[bainin]

I had been running a few xmas projects in pine and was nibbling at a 1/4 thick piece for cleanup when bam!-my 1/4 6TPI Timberwolf blade snapped.

Taking the cover off and removing the broken blade I started looking for reasons that such a wimpy piece of wood might have caused this.

I couldn't find anything.

I do use the carter bearing guide system and did notice that the lower guide bearings didn't spin easily when removed-i cleaned them as best I could and put them back in the tool.

Prior to the blade break, i had hand spun the blade around by hand and had not noticed any interference with the bearings and spun freely.

The only other thing i could think of is that a small cutoff piece fell down thru the table plate and wedged between a bearing and the blade-though I didnt find anything like that.

Anyways-just curious what kinds of errors on my part could lead to a snapped blade?

Is there anything I should double check before restarting ..possible damage to anything else in the blade handling system?

thanks !

b

[beeg]

Did it break at the weld or elsewhere? Was there a kink in the blade?

[RFGuy]

I don't have any guidance for what you might have done wrong, but just wanted to share a couple of manufacturer links that I found helpful in the past. There are those who will mistakenly tell you that bandsaw blades can't break at the weld. This comes from a misguided belief that welds are stronger than the adjacent metal. Not true (see excerpt below). It might be that you did nothing wrong and that the weld finally fatigued and gave way on that blade. It happens.

Excerpt:
"Unlike most other welding, a bandsaw weld is almost always the weakest part of the blade, even when welded by trained operators on the latest CNC welding equipment. So, if any other factor is negatively affecting the blade, there is a high chance the weld will be the first place to crack."

https://www.wolfmach.com/news/why-are-m ... -breaking/

https://www.sawblade.com/common-causes- ... blades.cfm

[bainin]

Heres some forensic pics for you detectives

It does appear to have broken at the weld.
It does appear to have a kink in it as well-though I dont recall that being there when I installed the blade a day ago.
There seemed to be some amount of wood pulp smashed into one of my lower bearings-possibly indication of a splinter getting in between the blade and roller?

bs-1.jpg (117.06 KiB) Viewed 1795 times

bs-2.jpg (57.92 KiB) Viewed 1795 times

bs-3.jpg (109.33 KiB) Viewed 1795 times

bs-4.jpg (69.68 KiB) Viewed 1795 times

b

[RFGuy]

Yeah, the welds are the weakest link on bandsaw blades, so not too surprising that that is where it broke. Also, the kink in the blade may have happened after the blade broke, so I would suspect the blade is the culprit, rather than anything that you did wrong. JMO.

If you get a new blade and it happens again, after confirming the guides are positioned well, then that is when I would take a step back to try to figure out what, if anything, you are doing wrong.

[jsburger]

How old is the blade? I would not expect a BS blade to last forever. Useful age is also a function of how much use it sees.

[john_001]

If it broke at the weld, it may be covered:

"Everything we sell has an unlimited time and performance guarantee. We guarantee all of our welds except on blades shorter than 65" in length or any blade that has been improperly sharpened. We do not, however, guarantee blades that are run on any three-wheel machine."

https://timberwolfblades.com/Suffolk-Machinery.php

[bainin]

Oh thanks John - I was wondering about that but hadnt got around to looking it up.

For total usage time...hmm I think I got them 1 year ago and to be honest only run the 1/4 blade for xmas ornament stuff...so total use time was likely under 24 hours.

b

[jsburger]

Obviously not an age/usage problem then.

[RFGuy]

Since your blade was fairly new with low hours on it, I think that tends to confirm a bad weld from the manufacturer. Advice I found on another forum indicated that likely your bandsaw blade was not sufficiently annealed. The process of welding hardens the steel and leaves it very brittle. Bandsaw blades have to go through annealing after welding to soften the weld metal to prevent a premature failure like you probably experienced. The manufacturer will likely stand behind their product and fix this. IF they give you a hard time, I would ask them about their welding process and how they anneal the welds afterwards.