Memory Crutch

[Blaughn]

Leaving a bandsaw blade in tension shortens the life and is so easy to do.  I had a piece of wormy oak laying around so I used it to help me remember.  (I am sure I am the ONLY ONE in the Scrollsaw Village that needs that kind of help!!)  The sign sits on the bandsaw table when the saw is untensioned and hangs from the shop door when the saw is tensioned so I have to duck my head to miss it.  

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[jerry1939]

Hi,  I've addressed this before.  Keeping steel under tension has no detrimental effect.  Some people also release the tension on their scroll saw blade when quitting.

Concrete is high in compressive strength and low in tensile strength.  When a bridge or overpass is poured steel is tensioned and the concrete is poured around it.  That steel (cables) remain in tension forever.  For those of you that are afraid of tensioned metal, DON'T EVER DRIVE OVER A BRIDGE!  That steel has been under constant tension since the day it was fabricated.

jerry

[Dan]

17 minutes ago, jerry1939 said:

Hi,  I've addressed this before.  Keeping steel under tension has no detrimental effect.  Some people also release the tension on their scroll saw blade when quitting.

Concrete is high in compressive strength and low in tensile strength.  When a bridge or overpass is poured steel is tensioned and the concrete is poured around it.  That steel (cables) remain in tension forever.  For those of you that are afraid of tensioned metal, DON'T EVER DRIVE OVER A BRIDGE!  That steel has been under constant tension since the day it was fabricated.

jerry

Apples and oranges. 

[Ron Johnson]

Good reminder Jerrry. I've gotten into the habit of releasing the tension on my bandsaw and scrollsaw each time I'm done. 

[Blaughn]

It is more than the steel.  The following is from the Timbersaw bandsaw blade website:

"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."

[JustLarry]

Releasing tension may help the tires from flattening out and possibly remove strain of wheel bearings and connecting shaft?

Sometimes I release, sometimes I do not.  So far I have not seen any results from either one, but I have only had my band saw for maybe 10 years?

Larry

I forgot to say I like the sign.

 

Edited March 26, 2018 by JustLarry
forgetfulness

[oldhudson]

28 minutes ago, Ron Johnson said:

Good reminder Jerrry. I've gotten into the habit of releasing the tension on my bandsaw and scrollsaw each time I'm done. 

I'm not sure about a scroll saw, but a band saw the blade in pushing against the tires, probably scoring them. I think I'll keep releasing tension on all the equipment. Only take a second and can't hurt.

[trackman]

21 minutes ago, oldhudson said:

I'm not sure about a scroll saw, but a band saw the blade in pushing against the tires, probably scoring them. I think I'll keep releasing tension on all the equipment. Only take a second and can't hurt.

If you forget to tension it back and start cutting, well bad things can an will happen.  I know from having done just that. Ruined a bland new blade lucky I didn’t get cut. Do like your sign. Only I would forget the sign lol. 

[Rockytime]

I don't release my scroll saw or band saw blade. Never had a problem. Course my blades are stupid and have no memory.

[Sycamore67]

As a metalllurgist, I do not think it makes a difference.  The temperature of the bandsaw blades do not normally get high enough to make a difference.  When tensioning the bandsaw blades you normally stay in the elastic region and if you stretch it , it will come back when you release the tension.  Of course, if you really over tension a smaller blade on your bandsaw, you could damage it.

[Dan]

If the blade or bandsaw manufacturer recommends it, it is probably best. They are the experts. 

[JTTHECLOCKMAN]

It is more about causing flat spots on the rubber wheels or urethane wheels if that is what you use. Then you get a thump. This is if you are leaving the bandsaw for long periods of time. I use mine quite often so I do not untension at all. I always do to the scroll saw after a cutting sesion. Just habit and so easy to see when I go to use again. Do not scroll as much as I use to. 

[jerry1939]

I bought a Skil band saw in 1994.  Not used all that much anymore.  Originally used to cut carving blanks, which I don't do as much anymore.  The ONLY time I touch the tension knob is if I try to cut too small a radius, break the blade & need to replace it.  It runs as good and cuts as true as the day I bought it.

To repeat my earlier post, Do Not Drive Over Concrete Bridges.

jerry

[tgiro]

I have never released tension on a band saw. I've never seen any of my blades, thick or thin, with a wheel memory in them. I have never noticed any deep groove in the tires on the wheels either. Since I installed wheel brushes, I don't even get blade tracks any more. I don't know about cracked gullets. I've never checked, although, that may be where a blade will break. If I have a broken blade, I dump it and replace. I don't try to repair them. I don't have the tools and sending them out for repair costs as much as a new blade.

Having said that, I do release tension on the scroll saw. I have no proof that it's a good or bad, or don't care, thing. But that's how i was taught and it's a habit.

[wedo scroll]

I release tension on both my band saw and scroll saw. I use a small block of scrap wood with LOOSE on it setting on my band saw table to aid my memory, if its not there its tight!

Works for me!

[OCtoolguy]

On 3/26/2018 at 1:29 PM, Blaughn said:

Leaving a bandsaw blade in tension shortens the life and is so easy to do.  I had a piece of wormy oak laying around so I used it to help me remember.  (I am sure I am the ONLY ONE in the Scrollsaw Village that needs that kind of help!!)  The sign sits on the bandsaw table when the saw is untensioned and hangs from the shop door when the saw is tensioned so I have to duck my head to miss it.  

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Great idea. I can never remember to loosen the tension on my bandsaw. This will make a great reminder.

Ray

 

[OCtoolguy]

On 3/26/2018 at 1:56 PM, jerry1939 said:

Hi,  I've addressed this before.  Keeping steel under tension has no detrimental effect.  Some people also release the tension on their scroll saw blade when quitting.

Concrete is high in compressive strength and low in tensile strength.  When a bridge or overpass is poured steel is tensioned and the concrete is poured around it.  That steel (cables) remain in tension forever.  For those of you that are afraid of tensioned metal, DON'T EVER DRIVE OVER A BRIDGE!  That steel has been under constant tension since the day it was fabricated.

jerry

I believe what you are saying but what about a car's springs? I've heard and always believed that the springs begin to sag after many years of having the weight of the car on them? Is that the same principle or not?

Ray

 

[Lucky2]

I don't know for sure if it does any good or not, but I loosen the tension on my bandsaw and my scrollsaw. And I loosen the tension on any other piece of equipment I own, that the tension can be released on. I don't need a reminder that the tension is loosened, because I've been doing this since I was in middle school. It was what I was taught to do, so I still do it.

Len

[JTTHECLOCKMAN]

Old school Len. That is the way it was taught. Right now there is tension on my bandsaw blade. I used it about 3 days ago and will be tomorrow or the next day. Will be milling some lumber for projects. As I said I use my saws quite a bit during a week. 

We can get into many different practices in a shop. Do people leave the blade up on the tablesaw when done cutting for awhile?. Do you take the router bit out of router after a project or leave it in till next project and you need to change??  Do you leave the router bit exposed in the table when done or do you lower the router?? Do you change sandpaper after a project knowing the next project will need new paper or do you wait until you use the sander again?? I have a million of them Would need alot of signs around the shop.

Edited March 29, 2018 by JTTHECLOCKMAN

[keithv]

I saw a YouTube clip where a guy suggested clipping a carabiner to the bandsaw blade while tension was off.   Don't recall what he did to remember to take the tension off and put the carabiner back on the blade....

[jerry1939]

14 hours ago, octoolguy said:

I believe what you are saying but what about a car's springs? I've heard and always believed that the springs begin to sag after many years of having the weight of the car on them? Is that the same principle or not?

Ray

 

I also believe that large truck springs will sag over time.  They are not tensioned when forged.  In a bridge, the cables are tensioned before the concrete is poured.  The cables support the weight of the bridge itself, plus the traffic on it.  The concrete provides the shape of the bridge.

Re: Band saw blades & scroll saw blades, it's quite obvious on this subject that it's just a matter of whatever makes you feel good.  For my own part (2 cents worth), I never mess with tension and have yet to see a problem.  My band saw is 24 years old.

A nap also makes me feel good.   

jerry

[OCtoolguy]

3 hours ago, jerry1939 said:

I also believe that large truck springs will sag over time.  They are not tensioned when forged.  In a bridge, the cables are tensioned before the concrete is poured.  The cables support the weight of the bridge itself, plus the traffic on it.  The concrete provides the shape of the bridge.

Re: Band saw blades & scroll saw blades, it's quite obvious on this subject that it's just a matter of whatever makes you feel good.  For my own part (2 cents worth), I never mess with tension and have yet to see a problem.  My band saw is 24 years old.

A nap also makes me feel good.   

jerry

I can't say one way or the other but since they recommend taking the tension off in the owner's manual, I got in the habit of doing it. But, I have forgotten many times and so far haven't seen any difference one way or the other. I'm not smart enough to make an educated decision on the subject so I'll just keep on doing what I have done in the past. FORGET to release the tension. Maybe with this reminder sign it won't happen quite so often. Thanks for your input Jerry. I read everything you post.

Ray

 

[jerry1939]

1 hour ago, octoolguy said:

I can't say one way or the other but since they recommend taking the tension off in the owner's manual, I got in the habit of doing it. But, I have forgotten many times and so far haven't seen any difference one way or the other. I'm not smart enough to make an educated decision on the subject so I'll just keep on doing what I have done in the past. FORGET to release the tension. Maybe with this reminder sign it won't happen quite so often. Thanks for your input Jerry. I read everything you post.

Ray

 

Re: "I read everything you post".  scary!

[CharleyL]

My method is less visible, but works quite well, for me. I have several red carabiners and hook one around the blade leaving it on the table. I've been doing this for over 20 years, but Steve Goode just posted it on his website. Oh well, I'm glad that he thinks it's a good idea. You sure can't use a saw with one of these around the blade, be it a band saw or a scroll saw. I hang them on some highly visible protrusion of the saw when the blade is tight and in use, then place it around the blade and leave it on the table surface when I release the tension. 

Charley