Bandsaw blade breakage

[Mead Camans]

Hi all,

I've just had a bandsaw blade fail on me and it's left me scratching my head.

The blade in question is Tuff Saws SuperTuff Fast Cut 3/4" purchased back in September.

It's a fairly thin blade at 1.5mm and developed a crack front to back between teeth.

I've had three of these blades and all have broken like this. The first two I assumed I was tightening too much, so I put this new one on a little slacker which seemed to work fine until now.

I've been using it pretty much every day since I got it, so it's had a fair amount of use, but I'd still expect to get more than 4 months out of it!

What's at fault here? Is this just an issue with thinner blades? Or is it a tension thing? My bandsaw doesn't have a tension gauge, so I take the advice of "tighten until it performs".

Any thoughts?

George

 

[Mead Camans]

UPDATE: Having examined the blade, there are five other cracks of varying sizes. In other words, multiple points of failure.

 

[Lazurus]

Give Tuff saws a call and see what they think, it could be a bad batch which they dont yet know about. And you may get a replacement

 

[Mead Camans]

Give Tuff saws a call and see what they think, it could be a bad batch which they dont yet know about. And you may get a replacement

Email has been sent in the least whingy tone I could muster.

 

[martin.pearson]

I would have phoned them, had some great advice from them over the phone & it makes it easier if they need to ask questions about your machine & set up to get to the bottom of what is going on. I take it you have checked the machine over for any potential problems with bearings & that sort of thing.

 

[MARK.B.]

5 cracks would indicate a flaw in the steel

 

[Mead Camans]

Had a response. My main take away was:

Tension – too low, it’s really difficult to over tension these blades and most of the time more tension is needed rather than less

Never considered I wasn't putting enough tension on!

Also mentioned was cutting stock too thin. Apparently these blades are meant for stock 1" plus.

Interesting!

 

[Jacob]

I've hardly ever had a breakage in years since I was told that it means too high tension. Blade needs to be only slightly tighter than the minimum to stop it slipping. Have had a few blades heavily used and beginning to show starts of cracks but I put that down to usage
PS just read the post above! Says exactly the opposite, oh well!

 

[Mead Camans]

I would have phoned them, had some great advice from them over the phone & it makes it easier if they need to ask questions about your machine & set up to get to the bottom of what is going on. I take it you have checked the machine over for any potential problems with bearings & that sort of thing.

I think I will phone in future yep. Bearings and whatnot are all good as far as I can see.

 

[Mead Camans]

I've hardly ever had a breakage in years since I was told that it means too high tension. Blade needs to be only slightly tighter than the minimum to stop it slipping. Have had a few blades heavily used and beginning to show starts of cracks but I put that down to usage

That is what I assumed! But they've told me almost the opposite. See last post.

 

[clogs]

sounds very much like a bad batch of steel.....
I'm sure Ian will sort you out.....
1 crack we'll say permissable but multiple on the same blade really does mean the blade is to hard...not annealed prop.....
it a marvel that the blades last as long as they do considering the thickness/strain and tension etc they suffer.....
that type of steel is a real work of art....

 

[recipio]

I use a standard 3 tpi from Tuffsaw and never had a breakage. Is that 1.5 mm an extra thin blade as in a butcher's bandsaw ?

 

[Mead Camans]

I use a standard 3 tpi from Tuffsaw and never had a breakage. Is that 1.5 mm an extra thin blade as in a butcher's bandsaw ?

It's one of these:

3/4" - SuperTuff Fastcut 2281mm - 2735mm

 

[Spectric]

Also mentioned was cutting stock too thin. Apparently these blades are meant for stock 1" plus.

Someone told me that you want at least three teeth in the material but no more than ten.

Looking at Tuffsaws info it says quote

The SuperTuff Premium and Fastcut blades are made from thinner material than standard blades and the main advantage of this is that a wider blade can be run on machines that usually struggle to run a wide blade. There’s also less waste and the blade is capable of running with more tension, which makes it a lot easier getting nice straight cuts. Another advantage of increasing the tension is that it improves the beam strength of the blade, which again makes straight cutting and setting up the bandsaw a lot easier.

 

[Mead Camans]

Someone told me that you want at least three teeth in the material but no more than ten.

Looking at Tuffsaws info it says quote

The SuperTuff Premium and Fastcut blades are made from thinner material than standard blades and the main advantage of this is that a wider blade can be run on machines that usually struggle to run a wide blade. There’s also less waste and the blade is capable of running with more tension, which makes it a lot easier getting nice straight cuts. Another advantage of increasing the tension is that it improves the beam strength of the blade, which again makes straight cutting and setting up the bandsaw a lot easier.

Ok then. Seems the answer is more tension!

 

[Spectric]

Thinking of a blade running without enough tension, it will deflect more and this could result in the cracks, think of an under inflated tyre where sidewall damage occurs due to excess deflection as it rotates. If the blade is tensioned tighter then this deflection will be minimised and it will cut straighter.

 

[TheTiddles]

Same as bolts, under tension means they see a higher cyclic loading and therefore more susceptible to fatigue, which will look like small cracks that start from a stress raiser like a tooth gullet and gradually grow each cycle until there’s a catastrophic failure.

 

[dzj]

I've been using it pretty much every day since I got it, so it's had a fair amount of use, but I'd still expect to get more than 4 months out of it!

4 months is a pretty good innings if used every day.

 

[baldkev]

Interesting thread.

I just got my new startrite home. So how do you guys know when your tension is right? Ive heard about twisting the blade side to side etc, but thats not very scientific
What do you do?

 

[Ttrees]

White finger test on the column side, or a ping is what I've been doing so far.
Deeper ripping is best done with a bit more tension when you need it,
but may be OTT of smaller cuts, no need to put strain on the blade if not needed
as you don't want hairline cracks to appear prematurely.