Bandsaw selection and need to release tension

[Adrian Mariano]

I'm thinking of upgrading my bandsaw, and since everybody recommends the Italian saws I was looking at them, but nothing coming out of Italy has a quick tension release lever on it. Without a quick tension release, I will leave the blade tensioned all the time. So far the only option I've identified with a tension release is the PM1500, and it may not fit in my shop (ductwork limits height to 79"---anyone with a PM1500 know the actual real height?).

So the question becomes: is it OK to leave the blade tensioned all the time? I have seen both answers to this question. It seems like the main concern is the effect on the rubber of the tires, and perhaps mainly for narrower blades. My expectation is that I will usually have a narrow (3/8") blade on the saw. So is it OK to leave such a blade tensioned all the time?

[Andrew Gold]

I had this concern when shopping for a new bandsaw as well, as my last bandsaw (sold about 10 years ago) had the quick release. I ended up going with an Italian saw, and have found it really easy to detension after each use.

It's not really an answer to your question... I guess what I'm trying to say is the quick release turned out not to be as important as I thought, and at least from my italian saw, I think what you gain more than compensates for what you give up...

[Joe Jensen]

There is a balance of people on either side of the "need to de-tension" bandsaw blades. I am an engineer and I can say with certainty that de-tensioning is harder on the blade than leaving it tensioned. But leaving the blade tensioned all the time will deform the tires a bit. Blades most likely wear out way before they extra strain from be tensioned and de-tensioned so that's probably not an issue.

From my own personal experience I bought a used Powermatic PM141 bandsaw from 1990-2009 and I never de-tensioned. I hadn't even heard of de-tensioning. My shop is in Arizona and it's super hot here a lot of the year. The rubber tires will deteriorate faster in heat and after almost 20 years of use on a used bandsaw and never de-tensioning the tires I had no noticeable tire deformation.

My personal opinion is that de-tension levers are just another "feature" that is solves a WW'ers nonexistent problem. Just a way to separate WW'ers from them money.

[Erik Loza]

....My personal opinion is that de-tension levers are just another "feature" that is solves a WW'ers nonexistent problem...

Agree 100% ^^^^^

That being said, I do suggest de-tensioning the blade (especially carbides, if you use those) at the end of each day. I have seen carbides put flat spots in tires if left under tension for a long time. Just a good habit to get into.

Erik Loza
Minimax USA

[Bill Huber]

I just have a little Jet 14" band saw and I added a Carter de-tensioner on it, I don't de-tension it every time I use the saw but most of the time.
The big thing to me is when changing blades, going from a 1/4" to a 1/2" the detensioner really make it much easier and faster.

[John Coloccia]

I de-tension if I'm not using the saw for a while. When I'm working in the shop everyday, as part of my startup routine I just casually grab the blades on the bandsaws as I walk by and give them a little spin to get them on a different part of the wheel. It's sort of like turning on the air cleaner. It's just one of those automatic things I've gotten into the habit of doing.

[Edwin Dodds]

I am a machinist with 32 years experience in the trade and have work in 4 different machine shops throughout my career. All of the shops I have worked in had at least one bandsaw in them, and never at anytime in my career did we "de-tension" a bandsaw blade when not in use. Some of the bandsaws were used daily, others only occasionally. In fact, I had never even heard of such a practice until I took up woodworking a few years ago, and came across some discussions such as this!
I don't see the need to de-tension, and have never seen any negative effects from leaving a blade on a saw under full tension all the time. Now granted, metalworking bandsaws are somewhat more robust than woodworking bandsaws. However, I have had my cast iron frame woodworking bandsaw with a riser block for about 5 years now, I always leave it fully tensioned and have seen no ill side effects.
I tend to agree with Joe's post - It's a non-existent problem!
The people that support de-tensioning - when they get home from work each day do they jack up their car to take the weight off the springs and release the tension in the suspension??

[Chris Merriam]

Also, detensioning an Italian saw is nothing like your standard 14in saw. It uses a large handwheel, conveniently located, and is easy to turn. It takes like 3 or 4 rotations and it's done, takes less than 5 seconds. It's so easy to do it's not even worth considering the de-tensioning debate. Now on the flip side, when you are going to start using the saw for the day, you will need to correctly set the tension on it using the handwheel, which will be a bit slower than just moving that quick release lever, but still, I spend maybe 10 seconds on it.

[Rod Sheridan]

I am a machinist with 32 years experience in the trade and have work in 4 different machine shops throughout my career. All of the shops I have worked in had at least one bandsaw in them, and never at anytime in my career did we "de-tension" a bandsaw blade when not in use. Some of the bandsaws were used daily, others only occasionally. In fact, I had never even heard of such a practice until I took up woodworking a few years ago, and came across some discussions such as this!
I don't see the need to de-tension, and have never seen any negative effects from leaving a blade on a saw under full tension all the time. Now granted, metalworking bandsaws are somewhat more robust than woodworking bandsaws. However, I have had my cast iron frame woodworking bandsaw with a riser block for about 5 years now, I always leave it fully tensioned and have seen no ill side effects.
I tend to agree with Joe's post - It's a non-existent problem!
The people that support de-tensioning - when they get home from work each day do they jack up their car to take the weight off the springs and release the tension in the suspension??

Exactly, I have 35 years in industry and have never seen a band saw detensioned................Rod

[Larry Frank]

I think that the issue of de-tension is also depends on the size of the blade. I have started using 1/8" and 3/16" blades on a smaller band saw and do de-tension them as I think that leaving full tension on the blade can cause some creep in the blade and leave too much stress on the small blades. I have found that you need to be pretty careful with these small blades or you can easily break them. On a larger blade, I do not think it makes any difference at all.

[John Coloccia]

The people that support de-tensioning - when they get home from work each day do they jack up their car to take the weight off the springs and release the tension in the suspension??

No, but when I used to go away on business for months on end, I'd have whoever was looking after my place move my car from time to time so I didn't develop flat spots on the tires.

[Roger Pozzi]

This topic got me thinking,,,,,,,,,,,
When I bought my Rikon bandsaw and got it unpacked in my shop, the blade was tensioned. How long had it been that way,,, I don't know. But, if tensioning was bad, I think the blade would have been packaged separately. Just my thought, I think I'll go out to my shop and tension my blade. :rolleyes:

[William C Rogers]

Very good thread. I had been de-tensioning my blade, just because I must have read it somewhere. Yesterday I forgot to tension it and turned the saw on, bam ruined that blade. From now on I am going to leave it tensioned.

[Matthew Hills]

Releasing tension with the MM16 is pretty easy -- a few quick rotations of the hand wheel. The handhweel is easier to reach and turn than the tension knob on my old 14".
I do release tension, but I go weeks at a time where I don't get to use the shop.

Matt

[Keith Hankins]

I have two BS's one 14 Delta from 1934 that stays on tension all the time (no lever). Never an issue. I have a 17" Griz, that has the lever but I've never used it. It has a laguna carbide blade for resawing. Never had an issue with either. IMO not necesarry.

[Mike Null]

I can't lend anything factual but i have an Emco 3 wheel band saw and I have most often left it tensioned. It breaks blades (usually 1/8, 3/16) like crazy. I recently purchased a Laguna 14-12 and I will de-tension it if I don't intend to use it for a long period.

[glenn bradley]

As mentioned, the amazing enigma of the bandsaw leads to many varied responses on tension, drift, coplaner wheels and de-tensioning. As stated earlier, you will get different answers; some just answers and some backed up by all sorts of "logic" and "documentation" :D. I run my saws at least every other day and so do not de-tension as much as I used to when I used them once a week or so. If I am not planning on using the saw for awhile (I am in the assembly stage or finishing stage of some piece) I de-tension. If I think about it at the end of the day or "suddenly" realize that I have not used the saw for awhile, I will flip the tension off. I think the statements about impact on tires, bearings and blades are all valid. You just need to choose your battle. When you drive, do you downshift or just use your brakes? There are water-cooler debates on the wisdom of either. Tastes Great! Less Filling! So it is with bandsaws ;).

[lowell holmes]

You can replace the tension knob on a Jet or Delta bandsaw with a crank for just a few dollars. Four revolutions of the crank de-tensions the blade.
I bought mine at Highland Hardware. I don't like the concept of a leaver tension control.

[cody michael]

You can replace the tension knob on a Jet or Delta bandsaw with a crank for just a few dollars. Four revolutions of the crank de-tensions the blade.
I bought mine at Highland Hardware. I don't like the concept of a leaver tension control.

can you post a link I would be interested in this.

[Thomas Hotchkin]

In the 1970's I worked in one of the largest Machine Shop on the West Cost, with more DoAll band saws then I can count on both hands. Some dating back to before WWII. The only time that any saw was de-tensioned was for blade changes. I do not de-tension my MM16 saw.

[Chris Padilla]

I just took a class from David Marks at his shop in Santa Rosa, CA. He has about 6 bandsaws of all sizes scattered about. He never de-tensions his either because it would just take too much time and they all seem to run fine regardless and his get turned on daily/weekly I'm sure. I have one bandsaw and it probably gets turned on once a month. I de-tension it when I'm done. I also lower my table saw blade below the throat plate when I'm done, too.

[Kent A Bathurst]

A solution looking for a problem, IMO.

[Matthew Hills]

can you post a link I would be interested in this.

try: http://www.highlandwoodworking.com/search.aspx?find=bandsaw+tension

[lowell holmes]

That's the one. I have the crank.

You might want to add one of the springs they have as well. I did.

[michael roughan]

Not to derail this thread, but because it seems to have some very informed WW's, how do you determine when you have the right tension? It would seem to me it's more important to be running the saw with the right tension than protecting the tires? I believe that was William's point in his previous post.

[lowell holmes]

The springs I recommended come with recommendations. With the springs, set your tension one stop lower than normal. If your saw is cutting properly without shaking and baking. your probably OK.

The Timberwolf blades tell you how to set the tension. You raise your guides to topmost postion, and standing behind the saw, lower the tension until the blade flutters, then tighten the tension until the flutter stops. After the flutter stops, add 1/4 turn.

Mark Duginske's book on mastering the bandsaw is a good read.

[Chris Padilla]

There are as about as many theories for tensioning the blade as there are for de-tensioning the blade! LOL Shall we start a debate about drift? ;)

I tension my MM20 by cranking it up and when I can't push the blade more than a 1/4" with my finger, I stop...might go another half turn if I'm in the mood.

[Keith Hankins]

Not to derail this thread, but because it seems to have some very informed WW's, how do you determine when you have the right tension? It would seem to me it's more important to be running the saw with the right tension than protecting the tires? I believe that was William's point in his previous post.

I use the flutter method that they good folks at timberwolfe blades espoused. Works for me, and pretty dang simple.
https://www.youtube.com/watch?v=z8zZuDosSy0

[Larry Frank]

I read through this thread and there were many who do not believe there is a need for releasing the tension on a band saw blade when not in use.

I recently bought some Timber Wolf blades that are made by Suffolk Machinery. I decided to write and ask them if they recommend releasing the tension and some of the logic behind it. This is the response that I received from Tom at Suffolk Machinery----

"You are somewhat correct. We do recommend de-tensioning to reduce stress on the saw but more so to reduce stress on the blade. De-tensioning is more critical to narrower blades than wider blades although tension/strain is relative to the size of the blade and sawing application. We run as much as 37,500 psi on wider blades such as our 2" x .052 thick blade vs. 9,000 psi on a 1/4" blade. Therefore, we recommend it on all blades. "

This answers my questions concerning what to do and I will release the tension when not in use. I know that there are many people who do no release the tension and several mentioned being in large machine shops. The use of the blades in those shops is different as the actual life of the blade is typically not that long based upon my experience in my working days. In my shop, I would like to get the maximum life out of my blades and equipment. In addition, with larger blades, the tension is not only on the blade but the springs, tire, bearings and frame. Releasing the tension would help increase the life of these components.

But like many other things in woodworking....there are always many ways of approaching the same issue.

[lowell holmes]

If you use the crank, all that is required to release the tension the blade is four ccw revolutions of the crank.

[Gus Dundon]

They said de tensioning the blade when not in use would lengthen blade life. I don't usually do that. It's completely fine.

[michael roughan]

Great video, the flutter test is simple and intuitive and probably something the more experienced WW's know well, but for us weekend warriors, it's good to know.
Nothing like You tube videos to make things clear, especially for those of us that have antique bandsaws with no manuals.

[michael roughan]

I always appreciate a video, thanks!

[Chris Padilla]

One thing's for sure, you won't HURT anything to de-tension the blade. :)