Do you reduce tension on BS blade when not in use?

[RayintheUK]

I have always de-tensioned my bandsaw ever since I've had it. My method of reminding myself is to drape a piece of red rag through the tension wheel so that it hangs down on the table. Little chance of missing that, even at my advancing years!

Ray.

[wassaw998]

I detension after use, but, regarding the blade cooling, I am not that quick. On a normal BS session I make a lot of cuts, and do a lot of tinkering around in between cuts, by the time I detension (for the day) the blade has heated and cooled many times. I just do not detension after each cut before the blade has cooled. If that's the main reason for detensioning, then, maybe I am wasting my time detensioning? I always thought the main reason was to release stress on the BS, and to relieve the tires from potential flat spots?

Also, of note, I always thought it odd that when my BS came out of the box, it had a blade on it, fully tensioned...

[Thom2]

I detension after use, but, regarding the blade cooling, I am not that quick. On a normal BS session I make a lot of cuts, and do a lot of tinkering around in between cuts, by the time I detension (for the day) the blade has heated and cooled many times. I just do not detension after each cut before the blade has cooled. If that's the main reason for detensioning, then, maybe I am wasting my time detensioning? I always thought the main reason was to release stress on the BS, and to relieve the tires from potential flat spots?

I never meant to imply that blade stretch was the ONLY reason to detension the BS, there are many reasons to do so. My point was directed at a question of 'how often'

[Ken Weaver]

Also, of note, I always thought it odd that when my BS came out of the box, it had a blade on it, fully tensioned...

That's the way my Rdigid came.

[RonT]

Blade tensioning! I’m reading concerns with frame bending, wheels out of round, blades stretching and flattened tires as a result of tensioning.

I’m a mechanical engineer; rest assured if you are bending the frame and causing wheels to go out of round, you have purchased the wrong saw. If that were the case, you would not be able to make a straight cut or keep the blade in place. True, some saws are stiffer than others but, blade tensioning will not cause that to happen without serious problems elsewhere.

As for blade stretch as a result of heat; the heat generated might cause a miniscule length change. The blade will cool before you can ever release tension.

The only reason to release tension would be to keep tires from going flat. Even at that, if the tire was made from an elastic polymer with no memory, it to would get its shape back as soon as the saw was started. I don’t know if such a rubber is available for this application.

My two cents!

[Ken Massingale]

Blade tensioning! I’m reading concerns with frame bending, wheels out of round, blades stretching and flattened tires as a result of tensioning.

I’m a mechanical engineer; rest assured if you are bending the frame and causing wheels to go out of round, you have purchased the wrong saw. If that were the case, you would not be able to make a straight cut or keep the blade in place. True, some saws are stiffer than others but, blade tensioning will not cause that to happen without serious problems elsewhere.

As for blade stretch as a result of heat; the heat generated might cause a miniscule length change. The blade will cool before you can ever release tension.

The only reason to release tension would be to keep tires from going flat. Even at that, if the tire was made from an elastic polymer with no memory, it to would get its shape back as soon as the saw was started. I don’t know if such a rubber is available for this application.

My two cents!

I'm not an engineer in anything, Ron. But my gut says you are absolutely correct.
ken

[Tom Miller]

...She promptly advised "Hims put tater tots in hims pocket and the boy kicks them".

That's about as a good a synopsis as any! I'm sure, if given a little more time, she'd have mentioned the "steak throwing" scene.

RonT -- I'm guessing most of us agree that the major concern is tire flattening. But, now that you mention it, I even wonder how much of a concern that really is with newer materials being used for tires, or if it's just a holdover from the old days.

Regards,
Tom

[LarryG]

I'm not going to directly disagree with Ron, or anyone else, on the need to detension; I honestly don't know. What I do know is that this is not just an advisory that's handed down from one woodworker to another, but rather something the manufacturers of the tools include in their manuals.

My Grizzly G0555 manual says:
"NOTICE
"All bandsaw blades will stretch. To reduce this stretching, remove the tension from the blade when not in use."

The Delta 14" bandsaw manual says:
"IMPORTANT: OVER-STRAINING IS A COMMON CAUSE OF BLADE BREAKAGE AND OTHER UNSATISFACTORY BLADE PERFORMANCE. RELEASE THE TENSION WHEN THE TOOL IS NOT IN USE."

Those are the only two manuals I've checked, but they essentially say the same thing. And I want to say that both Duginske and Bird advise that the blade be detensioned when the saw isn't being used, and I know for certain Scott Phillips once said to do it on an episode of "The American Woodshop." All this, and the few seconds it takes to do it, is reason enough for me to always detension my saw's blade. YMMV, etc.

[Thom2]

I'm no engineer either, but this is straight from Suffolk's site:

ALWAYS DETENSION YOUR BANDS

• When you are done cutting for the day, take the tension off your blade. Band saw blades, when warmed up from cutting, always stretch; and upon cooling shrink by tens of thousandths of an inch each cooling period. Therefore, blades, when left on the saw over tension themselves and leave the memory of the two wheels in the steel of the band, which will cause cracking in the gullet. When you leave the band on your saw under tension, not only do you distort the crown and flatten out the tires (which makes them very hard), but you also place undue stress on your bearings and shafts. Believe it or not; you can, and will damage your wheel geometry sooner or later and considerably shorten bearing life. You are also crushing your tires or V-belts.

TENSION
"The minimum amount of STRETCH you must apply to the body of the band to make it stable."
Always DETENSION the band immediately after use.

[LCHIEN]

My Delta BS manual says:

When the band saw is not in use, it is good practice to
release tension to prolong the life of the blade.

[Ken Massingale]

o.k., o.k., if it will make you guys sleep better, I'll detension my blade! ;-D

[paynea]

As a proponent of the "free insurance" and "belt-and-suspenders" doctrines, I always throw the lever on my Grizz G0555 after I'm done cutting for more than 5 or 10 minutes. I do the same with the lever on my little Delta scroll saw.

Even if it has no material impact, I figure there's really no upside to not detensioning.

Adam

[sacherjj]

When I had the Sears 10", I often forgot to detension. It was also a pain. Now, with the Carter QR, on my 14" saw there is no reason not to.

[cwsmith]

I've always understood that detentioning was best for three reasons:flattening of the tire, blade stretch, and relief of the compression forces on the tensioning spring.

I do agree that any heating and cooling of the blade itself should have neglible effects on blade stretch. Leaving the blade under tension may have negligible effects on the tensioning spring as well. I'm not so sure about the stretch of the blade or leaving a depression on the tire.

On my little Ryobi BS902 there is a quick release lever, but when you use it, the blade falls off the wheel. I still use it though, but open the door and hold the blade in place with a couple of clips first. I only do this at the end of a work period though. Removal of the switch key to a safe place is my reminder to fix everything before the next operation.

CWS

[Tom Miller]

On my little Ryobi BS902 there is a quick release lever, but when you use it, the blade falls off the wheel.

I wonder if there's some way you could limit the travel of the QR lever in the "released" position, to keep the blade from coming off....

Regards,
Tom