Bandsaw blade breaking

Apr 27, 2012 15 Replies

I fitted a nice new 6tpi bandsaw blade, it cut very happily, only used it for 2 days, always been gentle with it, and the bugger broke today. I noticed 2 things I wasnt expecting:


1 the blade is curved, it looks like the back has stretched, as if it had been pushed hard, but I've been totally gentle with it.


2 the blade and 2 of the 3 saw wheels were covered with firmly adhered clumps of sawdust.



I presume its down to the sawdust effectively enlarging the wheels and extending the blade path. Add to this that the tension adjustment is bolted tight and I presume thats what broke it. Are there any other possibilities? I'd rather check things now than after more blades.



Thanks,


NT


Did it break at the weld? Is there a 'cleaning brush' in the blade path? Does the tensioner not have a spring? I spose having 3 wheels that they're small so the blade has to flex more often around a smaller radius than larger 2 wheel jobs. Roddy will be along shortly with the correct answer.

I'll find out.

no, I wasnt using dust extraction either. My bad.

Yes. Theres also a clamping nut that, if not done up, lets the wheel wobble. I guess the solution is to do it up then back it off a tiny bit.

Yes, they're famed for premature breakage - but not after 2 days of work.

heh

NT

In message , NT writes

Inferior blade material with just the teeth induction hardened?

Could the guides be misaligned leading to heating and softening of the blade back? I think you might hear or smell that.

Have you been sawing knotty pine and the resin tacking dust to the blade and wheels?

regards

Things that need setting: blade tracking, upper and lower blade guides, and rear bearings. Where they all set correctly? As BM said, a blade brush helps and is easy to add if you haven't got one fitted.

I may be wrong but I very much suspect the machine rather than the blade. It turned out to be in a grim condition.

It was all set up

Wickes fence posts, I dont know what theyre made of, but the sawdust is stuck on pretty good, so I presume its resin. I'll use proper dust extraction in future.

NT

yes. I did run the saw for a bit with the top guides removed today to get that last little bit of height, but it broke later with the guides back on

Bit of steel bristled brush?

NT

yes. I did run the saw for a bit with the top guides removed today to get that last little bit of height, but it broke later with the guides back on

Bit of steel bristled brush?

I think mine is brass.

Or maybe nylon, can't remember.

good question: how do I know when tension is correct?

NT

Mine has a sprung marker. However, I never release the tension or bother checking:-)

regards

Try a paint brush head - mine has lasted many years

haven't got

I don't know but wouldn't the brush remove the dust before it gets compressed onto the blade by the rollers? What you are cutting will make a difference, a resiny bit of softwood will bung up any saw blade...

I'd have thought stuff that is already stuck on needs to be removed manually rather than hopefully brushed off.

I get the feeling people are underestimating how sticky this is. It seems I've got a problematic piece of wood, won't use it in future. To finish this project I'll use dust extraction and clean the saw out after each cut. Yes, it will need it, it only took one cut of a foot or so to clog the blade so much it broke.

NT

The brush is to prevent build-up, not to remove it.

If you're not using one already, switch to a skip-tooth blade.

If it's a 3-wheel bandsaw the wheels may be smallish so make sure you choose a sensible blade thickness for the wheel diameter - loads of info on-line but have a look here for a starter:

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assume that you fixed the tyre problem you mentioned earlier, and that the blade was tracked correctly)

This is the one thing I must still figure out.

NT

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