De-tensioning bandsaw after use?

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AES

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It may well do all of those things, but simply not necessary on a well made machine.

No harm in it if you want to do it of course, but it really is not necessary, or at least hasn't been for me for the last several decades of use :)

I certainly don't want to get into any arguments, especially when I don't have that much band saw knowledge paulm, I think a LOT depends on what tool you have. IF a band saw consists of a frame which is "just bent up" out of thin gauge sheet steel (meaning most of the frame strength comes from the bends themselves, which in my cheapo it certainly does, AND in several others I've seen) then as a fairly well-trained engineer myself, I'd "guess" it's a racing certainty that de-tensioning would be a necessity unless said band saw was in regular daily use. Mine certainly is not, hence de-tensioning after every use.
 
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TRITON

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I've neither snapped a blade nor taken the tension off in ten years.
Ditto, though 20 years for me.
I have heard it can create flat spots on the upper wheel, but if it has i couldnt tell you with my rattly old bandsaw.
Sounds like the saw blade is the problem, maybe had a crack in it.
Have you examined the rest of the blade to see if there are any other cracks ?

If theres none, email back to tuff ,quote what they've said and reply with WHAT A LOAD OF BOLLAKS.
 

AES

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Ditto, though 20 years for me.
I have heard it can create flat spots on the upper wheel, but if it has i couldnt tell you with my rattly old bandsaw.
Sounds like the saw blade is the problem, maybe had a crack in it.
Have you examined the rest of the blade to see if there are any other cracks ?

If theres none, email back to tuff ,quote what they've said and reply with WHAT A LOAD OF BOLLAKS.

But for the sake of at least trying to sound at least SLIGHTLY civilised TRITON, I'd recommend that you add to your "LOAD OF BOLLACKS" the phrase QUOTE: .... in my 20 years experience. UNQUOTE:

And IF you have an real engineering knowledge you may care to add QUOTE: It's most unusual for bent thin gauge sheet mild steel to crack. It usually just distorts before cracking, often so little that distortions can only be detected with straight edges and measuring tools. UNQUOTE:
 

Pineapple

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Funnily enough I am not allowed to join there 🤷‍♂️
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I have just tried to Register & I received an email; which said =
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Alexam

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For the blade to break ,other than at the weld, it would suggest that it was over tensioned. I consider that Ian at Toughsaw is a real expert on saw blades, but as far as letting off the tension between uses, I have, in the main, not bothered unless the saw is not going to be used for a long period of time and I generally use blades of 1/8" to 3/8". The odd breaks that I have had in the last 5 years have been at the weld, never in the blade itself.
 

paulm

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I certainly don't want to get into any arguments, especially when I don't have that much band saw knowledge paulm, I think a LOT depends on what tool you have. IF a band saw consists of a frame which is "just bent up" out of thin gauge sheet steel (meaning most of the frame strength comes from the bends themselves, which in my cheapo it certainly does, AND in several others I've seen) then as a fairly well-trained engineer myself, I'd "guess" it's a racing certainty that de-tensioning would be a necessity unless said band saw was in regular daily use. Mine certainly is not, hence de-tensioning after every use.
Interesting, but I have a cheap, lightweight Rexon machine as well as the bigger, heavier duty Startrite, and neither have been habitually de-tensioned over the last several decades, without any noticable detrimental effects.

I don't doubt your engineering expertise but, on this topic, my own and other folks real life experiences over many years is not imagined :)
 

Vann

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I have a big old (1928) 30" cast iron bandsaw. I de-tension at the end of each day - because I was taught to during my apprenticeship. I don't know if it's necessary or not, but as it's sometimes weeks between use, and it's no bother, I do it.

I remind myself it's detensioned by placing a slotted offcut on the blade (not that I need to as its a habit to retension before use).

Cheers, Vann.
 

TRITON

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But for the sake of at least trying to sound at least SLIGHTLY civilised TRITON, I'd recommend that you add to your "LOAD OF BOLLACKS" the phrase QUOTE: .... in my 20 years experience. UNQUOTE:

And IF you have an real engineering knowledge you may care to add QUOTE: It's most unusual for bent thin gauge sheet mild steel to crack. It usually just distorts before cracking, often so little that distortions can only be detected with straight edges and measuring tools. UNQUOTE:

Its a real world example AES. For 20 years Ive left the tension on.
Were this a problem, then my blades would be snapping all the time wouldnt they ?

So tell me why they dont.

Please avoid going on about technical understanding of engineering principle and just explain why my tensioned blades dont snap when you are tuff are suggesting that exactly what they should be doing. Because thats is in stark and direct opposition to tuffs reply.

A quote from 'Lumberjocks' on this tensioning subject

" I bought my bandsaw, a used Walker-Turner 14” bandsaw around 1960. In 55 years I have NEVER de-tensioned a bandsaw blade. And . . . . the blades just keep cutting just fine. So much for the de-tensioning in my way of thinking. "
Again, in direct opposition to tuffs explanation.

The way it looks, tuff are trying to get out of replacing a blade that clearly had a flaw of some sort in it.

So clearly and logically someone is wrong.

Tuff say its because they arent releasing the tension, and my and phils real world example flies directly in the face of that, which suggests VERY strongly that tuffs explanation is utterly incorrect.

So if you are willing to accept that AES, can you say what other flaws that would be in a blade for it to snap prematurely.
Cant be many examples for you to select from :unsure:
 
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Ttrees

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Most of Ian's blades are thin gauge, never had a blade snap from him, nor other.
It may well depend on if the blade is tensioned to the correct or somewhere close to the correct amount.
Some tension their blades to 25000 PSI.
With more folks opting for bigger saws these days, and have gizmos for tension, it doesn't seem like
he's trying to make excuses to me.

Jacob's post... "tensioned for the job at hand" likely makes sense for cambered tires, only little adjustment needed.
For flat tires...it would be a bit of faff though, as an under tensioned blade won't track with teeth off the wheels,
so you either have to undo the tracking knob for the blade to track in position at that tension, or set the thrust guide further back, and maybe wear a bit of your tires over time.
(might not be a bad thing, should one also use narrower blades on center of wheels, they'd be getting their moneys worth)


That takes some getting used to, if one is used to cambered wheels,
as it seems instinctive to turn the wheel whilst tensioning,
so you make sure you've tensioned correctly or the blade will dive into the thrust, and blade will want to be detensioned to place it in the right spot, not spinning the wheel this time round until tensioned correctly.

The benefit of the properly tensioned blade is staying on the wheels, with hardly any contact with the thrust when cutting, beam tension is the term used for that,
(i.e not needing guides for the job, apart from a thrust for safety purposes and not much else)
and is therefore a lot quieter machine to use.
I'd guess most who have a flat wheeled machine would choose to do the same,
choosing performance over longevity.

Tom
 
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sometimewoodworker

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For the blade to break ,other than at the weld, it would suggest that it was over tensioned. I consider that Ian at Toughsaw is a real expert on saw blades,

The odd breaks that I have had in the last 5 years have been at the weld, never in the blade itself.
The first statement is a guess and not supported by analyse. The break at a point other than the weld more strongly suggests that there was a fault in the blade at that site, that over time and continued flexing gave way, yes running the blade with too much tension can speed the development of the fault in the blade but unless you grossly over tension the tension itself doesn't cause the break

It’s the same with breaking at the weld. The welding process changes the structure of the steel and can make it susceptible to cracking depending on the skill of the welder, settings on the machine, skill in grinding, possibly even time of day.

The single mid blade break I have had was on a blade that wasn’t and had never been over tensioned, so far I haven’t put that blade back on the saw yet but since getting good blades here isn’t simple I will try it at some point.
 

AES

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Its a real world example AES. For 20 years Ive left the tension on.
Were this a problem, then my blades would be snapping all the time wouldnt they ?

So tell me why they dont.

Please avoid going on about technical understanding of engineering principle and just explain why my tensioned blades dont snap when you are tuff are suggesting that exactly what they should be doing. Because thats is in stark and direct opposition to tuffs reply.

A quote from 'Lumberjocks' on this tensioning subject

" I bought my bandsaw, a used Walker-Turner 14” bandsaw around 1960. In 55 years I have NEVER de-tensioned a bandsaw blade. And . . . . the blades just keep cutting just fine. So much for the de-tensioning in my way of thinking. "
Again, in direct opposition to tuffs explanation.

The way it looks, tuff are trying to get out of replacing a blade that clearly had a flaw of some sort in it.

So clearly and logically someone is wrong.

Tuff say its because they arent releasing the tension, and my and phils real world example flies directly in the face of that, which suggests VERY strongly that tuffs explanation is utterly incorrect.

So if you are willing to accept that AES, can you say what other flaws that would be in a blade for it to snap prematurely.
Cant be many examples for you to select from :unsure:


Triton, my only "objection" to your comment was NOT that your blades don't snap but your use of "BOLLACKS". As already said - clearly I thought - simply adding "in my 20 years experience" would make your statement far more polite - AND more likely to be accepted - AND probably something you would have probably added while discussing the subject in the pub or somewhere. But "each to his own" and all that.
 

AES

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Interesting, but I have a cheap, lightweight Rexon machine as well as the bigger, heavier duty Startrite, and neither have been habitually de-tensioned over the last several decades, without any noticable detrimental effects.

I don't doubt your engineering expertise but, on this topic, my own and other folks real life experiences over many years is not imagined :)

I don't "imagine" that your experience IS "imagined" paulm. It's clear from many other posts on this thread that some "do", and some "don't", those not doing so not suffering blade breaks.
 

J-G

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I've had three blades break over the past four years - I always buy 'Tuff' - and Ian has repaired two of them FOC as is his way. One broke at the weld and the other was elsewhere.

The third blade (not broken at the weld) wasn't repaired due to technical issues probably caused by over-tension and I had a personal phone call from Ian to explain why he thought a repair would be unlikely to be effective. Ian also suggested to me that "de-tensioning could be beneficial" and I suspect that that is exactly what was happened in the original communication, rather than "you must de-tension" and, as AES says, telling Ian that he is talking B**** is less than polite and totally inappropriate.
 

yetloh

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I now always detension my Felder 400 (Italian made andthe same as some Startrites). I have had some breakages of Tuffsaw bi-metal blades which are expensive but should last several time sthe life of standard carbon steel blades, but none since I adopted Ian's recommendation to detension after use. I am an itermittent user and the saw can easily stand unused for several weeksat a time. If left tensioned in these circumstances the sections of the blade around the wheels will have long periods when they are subject to additional stress so it makes sense to me that detensioning will be beneficial to blade life.

Jim
 
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