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Band Saw Tension

2184 Views 24 Replies 24 Participants Last post by  JoeinGa
I just changed the tires on my band saw and I thought this would be a good time to ask about something that has been bothering me.

Do you loosen the tension a bit at night and then tighten it back up when you are ready to use the saw?
Does this actually help with the life of the tires, blade and the machine?
Or is this just some old wives tale?

If it is worth it, then I will have to get into the habit of actually doing it. Maybe a sign on the band saw?

Any and all opinions will be welcome. Thank you, Uncle Stumpy
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I always release the tension with the attachment I got from Carters for my Jet bandsaw.
All I know is there is no way it couldn't hurt. Metal fatigues. May be a drop in the bucket but it's peace of mind.
Practical:
I release the tension if I remember to. I have not noticed any problems with leaving by bandsaw tensioned for several days. Since I have a lever tensioning system it is easy to tension / untension it. If I had one of those with the small knob that requires a lot of turning I might leave it tensioned.

Theoretical:
Recalling my engineering classes (almost 40 years ago) prolonged tension on a piece of metal can cause the metal to weaken and if around a curved surface cause the metal to want to conform to that curve. This could reduce the lifetime of the blade and increase flutter.

I can't recall any studies of how profound this is in real life.
I've been an electronics geek for much longer than I've been a newbie LJ.

Any electronics geek can tell you that one of the most persistent truisms (not sure if it has ever been adequately tested and proven, but "everybody knows" ) is that electronics last longer if you just leave them on all the time instead of turning them off when not in use. The theory is that all of that heating up and cooling down results in thermal expansion and contraction which, over time, weakens various things like solder connections and wire bonds inside the chips etc.

My thought when I hear this notion of "relaxing" and retensioning a bandsaw is that it would be more likely to work-harden some components and friction-wear others.

Plus it would be a pain in the backside.
I figured there would be arguments on both sides.

Constant relaxing and retentioning - metal fatigue. Check
Constant tension around a curved surface might cause the metal to conform to that shape. Check

Since I don't have a tension release mechanism on my Porter Cable machine it might be a pain in the neck.
BUT I just changed the tires and it was a MAJOR hassle. I watched videos on how to do it and after almost killing myself, I took the wheels off of the band saw and anchored them to my workbench. Still a hassle but do-able.

So in order to save wear and tear on my tires, I think a compromise might work - not releasing all the tension between uses but loosen it a little. Might help save the tires and blade and not be such a huge pain.
Anyone think that might work?

Thanks for all of the input guys! I knew some LJ's would have some excellent answers. Happy sawdust!
I was under the impression the other reason for releasing the tension when it is not in use is to avoid flattening the tires.

To remind myself, I always just place the unplugged cord near the tensioning knob to remind myself that I undid the tension
I did(releasing the tension in the bandsaw) 3-4 time, 7 years ago but then I decided to leave the bandsaw, tensioned and ready to use all the time,I figured the blades are going to get dull and get thrown away before the metal fatigue makes them unusable.
As far as saving the new tire I just put on , the last set was on the saw for more than 10 years so I guess for me changing the tires every 7 to 10 years is acceptable .
The bottom line: if you can get into the habit of doing this tensioning it in the morning/releasing it at the end of the day, as others mentioned, go ahead and do it since you won't hurt anything and it gives you peace of mind.
I had a 12" Sears for 15 years still have it. Never loosened the blade to big a pain put new tires on it about a year ago.
I now also have a 14" Jet that I put the Carter detensioning attachment on Use it when I remember. Several times I have forgotten to retension the blade when I use it. That is even with a big red ball right in front of me.
I really don't think it matters you will dull the blade before damaging anything.
dstrbd says it best.
I detension mine. But mine is a 14 inch with a riser. Also it may be a month or more between uses.

For a band saw that sees almost daily use, I don't think nightly detension is necessary.
My Grizzly G0555 has a lever to drop the tension but personally, I use that saw so much I have never dropped the tension in the 10 yrs I had it and there are no ill effects. The thing is that with my memory as bad as it is, I would more likely forget to put the tension back on and then run with low tension much of the time.

Cheers, Jim
Ah, one of my favorite topics. First off, I'm sure you are all right. However, I have had my Craftsman 12" band saw since 1972, and I have never changed the tires- and I have never de-tensioned the blade. Well, not exactly correct: I de-tensioned it once and then forgot to re-tension it later and the blade went cater-wampus and scared the you know what out of me.
My Jet 14" was only 10 years old when I had to replace the tires because they literally blew off the wheels. I put on the urethane tires and have had no problems since then. It has also never been de-tensioned.
My blades probably last as long anybody's blades- as mentioned, they will get dull before they break, most of the time.
I made a small sign on a magnetic backing that I keep at the start button to help me remember to re-tension the blade. A tensioning lever makes the process of loosening the blade much quicker. I also had one incident before making my small sign when I started the bandsaw and the blade came off. It can scare the poop out of you.
Never detensioned on my 14" Delta because it was a hassle. Always detension on my Grizzly 17" because it's easy to do. In terms of wear and tear on the Delta, no clue because it always cut crappy until just before I sold it I actually set it up right in preparation for selling it to a fellow woodworker. And then it cut really well, which made me sort of regret getting the Grizzly until I had to resaw 11" walnut and then my regrets disappeared into pure joy. I'm going to jump on the bandwagon that if you use it regularly, detensioning is unnecessary. Based on science? No. But heck. I'm entitled to my own opinion goshdarnit. ;)
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I de-tension mine and as others have stated it is a PITA. I acquired a box of tools at a yard sale and there were three braces in the box. I already had two so I put some flats on the rod that goes to the tensioner and voila. I have since cut the top of the brace off so just the middle handle is there WORKS LIKE A CHARM.

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I de-tension at the end of every day. Put the lock in the switch to remind me to tension. Just a habit, and the way I was taught years ago.
Bill
I only take the tension off of mine because I have a Grizzly and all you have to do is flip the lever. In thinking about it I feel like it holds weight that is wont keep constant pressure on the tires and you're not always holding tension on the blade. Supposedly your blade will start to not ruin smooth because of memory of the shape where it has been sitting with tension and the same goes for the tires.

I didn't come up with the idea but I saw someone make a stop sign out of scrap wood so that is what I do. I took a small scrap of wood about 4×4 and cut out a stop sign then painted it red. When I take the tension off I throw it in front on the blade to remind myself.
My BS has a lever and I take the tension off when not in use. All the years I worked in a shop we never released the tension on bandsaws and never had any performance problems. I hope this helps.
I have a 16" Minimax that I de-tension when running 1-1/4 re-saw blades, mainly due to the very high load these blades place on the frame and wheel bearings.

For smaller blades (1/2 for instance), I don't think twice about it.

In my opinion, if you have a convenient tension lever, may as well de-tension if you are not going to be using it soon just to keep the dust off of the lever, other wise let it go.

How you keep your other tools set up? Do you unplug and crank down the table saw blade after a days work? (I do). Do you remove the blade form the arbor? (I don't).

Neither of these really affects the life span of the table saw and blade, but it is just what I do.
I believe the concerns would be:

1) How well built is your saw?

2) How much pressure is being put on the wheel and tires by the blade?

and

3) How often do you run the saw?

If the wheels are made of cast iron, rather than aluminum, if they are fairly heavy duty and/or if they have several spokes, I would think they could tolerate a lot of pressure over a long time.

If the saw is run everyday, then the pressure is being moved around the tires and wheel, as others noted. As such, there shouldn't be enough time to cause damage.

Lumber and shake mills never detension their blades. After all, time is money. Of course they are made of pretty good iron.

Meanwhile, back at my ranch, I have a Carter release and use it religiously, just in case.
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