How long should a bandsaw blade last?

[OscarG]

Just had my weekend ruined by a broken bandsaw blade (that'll teach me not have a spare!).

It's a 6 TPI 1/4 inch, Tuffsaw blade but I've had it 10 months, that sound about the right lifetime for a blade used only at weekends?

Close up of blade..

What's odd is it broke cutting really thin stock, 3mm thick hardboard.

My dust extraction is a bit poor, you can see the build up inside machine, does that shorten life of blade?

 

[skipdiver]

Don't think there are any hard and fast rules. Ten months aint bad for a blade that costs about a tenner. They are under tension constantly (unless you slacken off after use), so it's just one of those things really. Buy two blades next time, then just the one each time you swap the old for the new.

 

[Myfordman]

Totally the wrong blade for the job. Aim to have 3 teeth at least in contact with the work. So for 1/8" thick you need at least 24 tpi.
Minimum thickness work of that blade would be 1/2"
No wonder it broke!

 

[NazNomad]

Is it broken at the weld? They usually do.

 

[Jacob]

Broken blade means either; too tight (common), poor weld (rare), a lot of use - but usually will have been blunted and re-sharpened a few times first

 

[ED65]

I think there isn't even going to be a rough estimate on this that would be of much help without context. One person will get a few years from a single blade because of lighter use in softer woods, another might get only a few months because they're sawing hard woods all the time and of greater thickness. And cutting curves can put way more strain on the blade than straight cuts so you might expect the weld/braze to fail sooner if you're doing a lot of them.

 

[OscarG]

Totally the wrong blade for the job. Aim to have 3 teeth at least in contact with the work. So for 1/8" thick you need at least 24 tpi.
Minimum thickness work of that blade would be 1/2"
No wonder it broke!

Wow...really?

I'm not doubting you, but just trying to understand, how does stock too thin cause it to break?

 

[transatlantic]

Totally the wrong blade for the job. Aim to have 3 teeth at least in contact with the work. So for 1/8" thick you need at least 24 tpi.
Minimum thickness work of that blade would be 1/2"
No wonder it broke!

Wow...really?

I'm not doubting you, but just trying to understand, how does stock too thin cause it to break?

I can understand how you might get a poor finish but for the blade to break because the workpiece is too light sounds a bit odd? surely it would be the other way around

 

[OscarG]

Totally the wrong blade for the job. Aim to have 3 teeth at least in contact with the work. So for 1/8" thick you need at least 24 tpi.
Minimum thickness work of that blade would be 1/2"
No wonder it broke!

Wow...really?

I'm not doubting you, but just trying to understand, how does stock too thin cause it to break?

I can understand how you might get a poor finish but for the blade to break because the workpiece is too light sounds a bit odd?

Yeah, that's what I thought. But I'm a complete novice with bandsawing, so I'm very happy to be corrected!

I'd like to go from 6 TPI to 4 TPI as the 6 seems to struggle to cut anything thick. I'm concerned now that having a 4 TPI blade means cutting anything under 3/4" thick might cause it to break! That's no good.

 

[sunnybob]

heres some reading for you.
http://www.allbandsawblades.com/how_to.htm

 

[PAC1]

You will find you need a range of blades depending on what you cut. It is possible to keep the number down to two or three by compromising between "ideal for" and "OK at". If unsure email Ian at tuff saws and ask what would be best. If you tell him the full range of activities that you usually carry out he should be able to recommend some choices. I try to have one for general use which is on the machine ready for when you just need to cut this (3/8th M42 blade). I then have one for very fine curves and one for deep ripping.
Some say you should take the tension off when it is not in use (during the week in your case). The alternative argument is that if you are changing the tension weekly you are more likely to cause fatigue.
As for how long a blade should last, it is a bit of a difficult question as it depends on many factors.

 

[Dan j]

I used to have a problem with blades breaking. The weld is always more brittle than the blade as it doesn't get tempered like the steel in the blade.
My bandsaw gets a moderate amount of use, often in hardwoods. I switched to buying blades with a guarantee on the weld about 3 years ago. Haven't had a blade break since.

 

[twodoctors]

Personal experience and what Ian J told me.

I have a baby bandsaw using 1400mm blades. I have had 2 3/16" Tuff Saw Carbon blade broken now. I think the blade is set up correctly, with correct tension. The last blade lasted about 4 bandsaw boxes (small ones) but with a fair few tight turns, cutting sapele, oak, walnut, zebrano in various combo. Spoke to Ian today and he says it's fairly common with smaller blade/saw as there's little time for the blade to cool down between cuts.

So what do I do? I bought another 2 of the same from him! :-D He sent the first replacement for free, plus threw in a Tuff Saw 3/8" 10TPI blade for me to try also for free.

Your poor dust extraction may have a part to play. Speak to Ian but from my limited experience and only with baby bandsaw so far, 10 months sounds like a decent amount of time. Did the blade feel blunt when cutting thicker stock?

Adrian

 

[Jacob]

I used to have a problem with blades breaking. The weld is always more brittle than the blade as it doesn't get tempered like the steel in the blade.
My bandsaw gets a moderate amount of use, often in hardwoods. I switched to buying blades with a guarantee on the weld about 3 years ago. Haven't had a blade break since.

Some welds can be stronger than the blade - I've had well used blades starting to crack up before the weld itself went.
If the weld goes often, try less tension and/or new supplier.

 

[chaoticbob]

By one of those coincidences which happen more often than they ought, I logged on to the site tonight to ask almost exactly the same question as the OP. In my case the (Tuffsaws) 3/8 x 3pi blade, on a Record 350S went bang when slicing up some 5mm plywood for kindling. OK, I know about the 3 tooth engagement thing and I was taking a chance, but it had worked so many times before without fuss...
The blade broke at about the ten o'clock position on the top wheel. Can anyone expain how that would have happened by my using the wrong tpi for the wood thickness? Like the OP I'm open to suggestions, being new to this.
I suspect I'd overtensioned the blade though, as Jacob suggested, and it was just waiting to happen.
Rob

 

[Noel]

The teeth are covered in hardened crud and many are blunt. Clean your blade periodically, making the blade thicker than the kerf is asking for trouble as it puts the blade under load and creates heat. Blunt teeth are a blade breaker too. No blade will last under those conditions. You were lucky to get so long out of it.

As mentioned I think at least 3 teeth should be cutting at any one time. With that TPI and such thin material only one tooth is effectively cutting at any one time. This puts extra tension and load on the blade and with the teeth blunt and covered in dry, burnt sawdust and crud along with glue residue from lam sheets....well you get the picture.
Clean, sharp blades are good : )

PS- good idea to learn to sharpen blades too, easily done with a Dremel or sharp file.

 

[stuartpaul]

Totally the wrong blade for the job. Aim to have 3 teeth at least in contact with the work. So for 1/8" thick you need at least 24 tpi.
Minimum thickness work of that blade would be 1/2"
No wonder it broke!

Right in principal of course but how many people change blade for a couple of quick cuts in thinner material? I doubt that in itself caused the breakage.

In depends what the majority of your cutting is. My saw spends it's life with a 1/2 inch M42 in it and it cuts absolutely everything (re-sawing 8 inch boards as well as cutting hardboard). Can't remember the last time I put a different blade on it.

 

[worn thumbs]

Some good points have been raised so far and I would like to add one more.The size of the machine makes a difference and likely had a part to play in this case;the smaller the wheels are-the greater the amount of flexing necessary to get the blade round and the sooner fatiguing is likely to aid the failure of the weld.A good while ago I had a Burgess bandsaw (still regret selling it) and bought some 1/4 inch blades from a company and while they cut beautifully they broke a lot sooner than the Burgess own brand blades which were much thinner.In a different context I had four years of everyday use from a tungsten carbide grit blade on a 32 inch Wadkin with the corresponding radius much gentler than a small saw.I have never been entirely convinced by the custom in some workshops of releasing the blade tension every day.I suppose it depends on the tensioning mechanism and the rigidity of the frame.I would be quite happy to leave the tension on a saw that uses weights to apply tension as the load is constant.With a threaded adjustment the temperature changes in a workshop might make a difference but each tensioning and slackening adds a load cycle.
I agree with the point about three teeth in the workpiece being the standard to aim for but in the majority of cases we make do with whats in the saw unless a big job crops up.I would rather face a job with a blade thats too coarse then struggle through a thick piece with too fine a blade as the only real drawback is the quality of the cut and maybe some splintering of the underside if a false table isn't in place.As the previous poster does I use a 1/2 inch blade for everything and it works.

 

[OscarG]

Thanks to all the people who've chipped in with advise, hugely appreciated. I wasn't doubting it but I was struggling to understand how too thin stock could affect the blade, I couldn't find anything online to explain the science. I have just heard from Ian at Tuffsaws (great bloke, who patiently answered all my questions!).

From the horse's mouth...

6tpi is the wrong tooth pitch for 3mm stock though and you would be better with ideally a 14tpi or 10tpi at a push – if there’s not enough teeth in contact with the wood when it’s being cut it produces more of a chopping action than cutting action and this leads to increased blade vibration/resonance that will then eventually lead to the blade breaking.

My bandsaw is a Record Power BS250 10".

One thing I forgot to mention, I cut a lot of MDF stuff, most 12 or 18mm thick to make templates (I'm an amateur guitar builder), Ian said that MDF is a nightmare for bandsaw blades.

So it sounds like need 2 bandsaws, one with a nice big 4 tpi blade and maybe a cheaper smaller bandsaw with 8-10 tpi to cut anything thin/MDF stuff. Either that or I'll be swapping blades every 2 mins.

 

[OscarG]

The teeth are covered in hardened crud and many are blunt. Clean your blade periodically, making the blade thicker than the kerf is asking for trouble as it puts the blade under load and creates heat. Blunt teeth are a blade breaker too. No blade will last under those conditions. You were lucky to get so long out of it.

As mentioned I think at least 3 teeth should be cutting at any one time. With that TPI and such thin material only one tooth is effectively cutting at any one time. This puts extra tension and load on the blade and with the teeth blunt and covered in dry, burnt sawdust and crud along with glue residue from lam sheets....well you get the picture.
Clean, sharp blades are good : )

PS- good idea to learn to sharpen blades too, easily done with a Dremel or sharp file.

Thank you, I take your points!

How do you clean your bandsaw blades?