Why release the tension?

[Steve Rozmiarek]

I've got a couple bandsaws, the one in question being a 14" Delta. It is exactly as it was when it left the factory, except it's on it's 10th or so blade, and has new cool blocks. I use it for the odd job saw, so it gets used often. I was using it tonight, and I got to thinking, the last time I remembered to release the tension was probably when the last blade went on. That was a while back, maybe a year? Come to think of it, I haven't religiously released the tension since I bought it used, many years ago. There is no vibration, and the saw works just as it did when we first met.

Am I missing something, or is the conventional wisdom on releasing the tension a little overblown? Opinions?

[Myk Rian]

It relieves the tension on the bearings and tires.

[glenn bradley]

+1 on bearings and tires but, as often as you use yours, the impact is probably minimal. I will sometimes not use my larger saw for a week so I release the tension.

[Ken Fitzgerald]

I think the main reason is to release pressure from the tires and putting a "spot" on them. I would think if you are using it daily that might not be a problem. If you are like me where you only use it once a month or once every two months...then I'd think it might be more of a problem.

[Bill Keehn]

Well, I consistently tension my blades beyond what is recommended by the blade manufacturer or the saw tension gauge. Sometimes I back it off to what is recommended and I call that relieving the tension. I've never had a problem.

According to David Marks you are spot on. He said he's always left his saws over-tensioned and it's never been an issue.

[Leigh Betsch]

I rarely remember to relieve the tension on my MM20. I'm sure it can't hurt but I don't think the MM manual says any thing about backing off the tension. I've never heard of relieving the tension on industrial metal cutting band saws. Does the Delta manual say anything about relieving the tension?

[Steve Rozmiarek]

Good point about the metal cutting bandsaws. Neither of those in our shop get backed off either. I'm in the woodshop daily this time of year, but maybe weekly if I'm lucky in the summer, so I'd think that the range of use would bring on a problem if one where going to show up.

[Paul Atkins]

Maybe the new saw cast iron is not very good and they need some sort of disclaimer " Oh, you didn't release the tension" when it breaks. How's that for negativity?

[james gerus]

The only time I had a problem leaving the band saw tensioned on was in an unheated garage seems Chicago winters can cause the wheels to warp

[Frank Drew]

I recommend it to avoid putting a permanent groove in your band saw's tires. Granted, it takes a long time for that to happen, but we intend to keep our tools for a long time, don't we? Most old saws tires I've seen have that groove worn into them.

Releasing the tension takes maybe 15 or 20 seconds to do and very quickly it can become part of your normal shop routine, like turning off the lights or the heat; you don't need to retension until the next time you use the saw.

[Bill Keehn]

Frank, I see what you are saying. OTOH, it's just as easy to forget to retension the blade before you use it as it is to release tension. Then you have a potentially dangerous situation if the blade slips off the wheels. I've had that happen a few times and it scares the heck out of me.

Flat spots take a fairly long time to develop and tires are replacable.
In the meantime I have a saw that is precisely tensioned the way I like it and is good to go anytime.

[Jamie Buxton]

If springs were damaged by being under constant tension, and if rubber took a set from being under pressure, we'd all be putting our cars up on blocks over night.

[Darl Bundren]

OTOH, it's just as easy to forget to retension the blade before you use it as it is to release tension.

I kept forgetting to release the tension on my saw and I didn't want to start it up with the tension released, so I hung a little cardboard sign over the on and off buttons that asks, "Tension?"

This allows me to concentrate on other aspects of the project to mess up.

:D

[Rob Damon]

I only use/have Timberwolf blades for my Steel City, so I do, but only because of this:

http://www.suffolkmachinery.com/six_rules.asp

Rob

[Cody Colston]

Well, I consistently tension my blades beyond what is recommended by the blade manufacturer or the saw tension gauge.

Me, too. I use Timberwolf blades but I don't subcribe to the low tension theory. I don't relieve the tension on my 17" band saw, either, and I'm gone for two weeks every month.

I'm not saying that is the correct method, just that it's my method and so far I've not had a problem.

[Mark Singer]

I had a Trimaster break because it was tensioned all the time , now I un tension each day I work

[Frank Drew]

Jamie, automobile tires absolutely can develop flat spots if left too long in the same position without moving. And I'd expect to keep a band saw for decades, not a couple of years.

I didn't come up with the idea to release the tension -- Oliver, the maker of my last band saw, recommended the step when they sent back my wheels after replacing the tires.

[Bill Keehn]

I only use/have Timberwolf blades for my Steel City, so I do, but only because of this:

http://www.suffolkmachinery.com/six_rules.asp

Rob

Rob, yep thats the best reason I can think of to do it. The timberwolf blades are "special" low tension blades, so you would think if something requires detensioning those would. David Marks specifically mentioned he likes these blades, but went on to say how he ignores their recommendations and does what he feels gives him the best results, which is over-tensioning. If it shortens the life of the blade or tires, so be it. Relative to the cost of the woods he uses the parts are cheap and easy to replace.

I happen to use a 3/4" Timberwolf on my Jet 18" for resawing & cutting veneer and thats all I use it for. I took a veneer class from Marks at the local Woodcraft, so I decided to follow his example. Now if there were a Carter quick release for the 18" I'd probably use it just in case. That's what I did with my old bandsaw, a 14" Powermatic along with using Darl's idea.

[Sonny Edmonds]

I don't release mine.
Never have, probably never will.
It runs and sounds and cuts the same as when new. Maybe a bit better.
I did make it 240 volt and that made a difference.
Mine has a tension gauge. It in fact has proven to coincide with Timberwolfs tensioning advice. (Who's blades I run, mostly.)
Haven't broke any blades (Knock on wood :p )
And my wheels are as true as they ever were.
But hey, do what you will in your own shop. :)

[Paul Atkins]

Car tires may get a flat spot, but they only sit on one spot - the band saw blade sits on 1/2 of the wheel - on a 20" saw this is over 30" on each wheel - It may not be equal force all the way around, but that is 60" of contact for a 150" blade. I'm not sure you could get a flat spot. I know I might forget to tighten the blade each time I use it - so I don't loosen it. Plus it gets used every day.

[Andy Pratt]

I never did it with my bandsaw until I broke a blade, then I started it and haven't broken one since. Just one instance, so it's definitely not a controlled experiment or anything, but here are the details:

I think it was a 5/16" timberwolf blade, not positive though. I had left it tensioned, on the high side of the recommended setting, for about a month or so without using it. When I went to use it, the blade broke immediately on startup. Since then I've always released the tension (carter system) as that was the only thing I could think of that I had done differently than all the other times I had used it without breakage.

Again, this is just one instance and I'm certainly not sure it wasn't a faulty blade or that I didn't overstress it with the tension or my sawing technique, so take this for what it's worth.

Andy

[Steve Rozmiarek]

Well guys, for what it's worth, I'm going to continue my no detension "experiment", until something breaks. I will detension the big saw, but not the little one. Not expecting anything interesting to happen, but I'll let you know if it does.

[Rod Sheridan]

Well guys, for what it's worth, I'm going to continue my no detension "experiment", until something breaks. I will detension the big saw, but not the little one. Not expecting anything interesting to happen, but I'll let you know if it does.

I'm with your approach Steve.

I've never released the tension on a bandsaw at home, or at work, and have never experienced a problem.

The only rolling element bearing problem I've seen happen to stationary bearings is Brinelling, and that's only happened to stationary bearings that are subject to vibration or shock loads while not rotating.

regards, Rod.

[Steve Rozmiarek]

I'm with your approach Steve.

I've never released the tension on a bandsaw at home, or at work, and have never experienced a problem.

The only rolling element bearing problem I've seen happen to stationary bearings is Brinelling, and that's only happened to stationary bearings that are subject to vibration or shock loads while not rotating.

regards, Rod.

Rod, I'd suspect that Brinelling is wear on one spot of a roller bearing, kind of a flat spot, correct?

[george wilson]

I have had a Delta 14" bandsaw since 1964,when I bought it used. I never release tension,and am afraid to,because my wife (who dosn't mix with machinery well) uses the bandsaw to cut plastic. I just know she would start the saw up with the blade slack. Take my word for it! Anyway,no problems have ever developed for mr. I still can't say that releasing tension isn's a good idea,seems logical,but it hasn't hurt me for many decades.

[Jim Chilenski]

Steve,

I believe that the "release the tension" thought came about because of the number of failures of the tracking arm that holds the upper wheel shaft on a 14" Delta bandsaw. This is the triangular piece of alloy die casting that is hinged to the tension control housing.

What will happen over time is that excessive tension will cause the hole that the shaft passes through to become elongated, making it harder to keep the blade tracking true. Once this occurs the only solution is to replace the assembly.

This has been identified as the "weak link" in the Delta 14" design. Iturra Design markets a beefed up version of the tracking arm and tension control housing which is suppose to hold up longer.

But I suppose that over time, with enough tensioin, it can fail as well.

YMMV
Jim

[Joe Von Kaenel]

Steve,


I read "The Band saw Book" by Lonnie Bird and "The New Complete Guide to the Band Saw: Everything You Need to Know About the Most Important Saw in the Shop (http://www.amazon.com/New-Complete-Guide-Band-Saw/dp/1565233182/ref=sr_1_2?ie=UTF8&s=books&qid=1233595454&sr=1-2) by Mark Duginske. Both authors recommend detensioning the blade to save wear on the tires and the bearing. I bought a Carter Quick Release™ (http://www.carterproducts.com/product.asp?product_id=20&cat_id=16) because it was such a pain to tension and retension the blade. This item works by moving an arm down to release the tension and moving it up to retention the blade.

It sounds like a lot of Creekers don't detention theirs blades and don't have problems. This is just a method I use. Hope this helps.
Joe

[Jeffrey Makiel]

For over 20 years, I've never de-tensioned a blade when not in use. And, my bandsaw is only used intermittently in my hobby. I've grouped this practice in the same category as PVC duct blowing up my home, polyurethane glue being stronger than yellow glue, and using blade stabilizers on my tablesaw to reduce vibration.

However, I do wear a garlic clove around my neck when doing final assembly.

-Jeff :)

[Rod Sheridan]

Rod, I'd suspect that Brinelling is wear on one spot of a roller bearing, kind of a flat spot, correct?

Yes Steve, it's actually a depression in the outer race the same shape as the rolling element (ball or roller).

Obviously the bearings are fine with the static loads imposed upon them, it's the "hammering" effect of vibration that causes Brinelling. (Often seen on bicycle and motorcycle stearing head bearings).

Regards, Rod.

[george wilson]

I wonder if the tension release arm is just something else to make us think we need it? And,does the blade stay in contact with the wheel when it is detensioned? Does the blade fly off the wheel when you retension and start the saw? Either way,I KNOW my wife would never remember to retension the blade. She uses the bandsaw once every several months.My wife has other talents,don't get me wrong. She runs our home business(mostly her's) very well.She has incredible ability to find some obscure article in a 1940's magazine that I looked at 5 years ago (and showed her),now lost in hundreds of old magazines. We are a team. Each helps the other's weak points.

[george wilson]

A P.S.. Being in a major museum for 39 years,I have met a lot of well known people,among them authors. I think that craftsmen who build things build things. Some people like to write books. I had a well known woodworking author tell me that he had had the same blades on his planer for 20 years. When he did grind them,he had rigged up a jig to grind them on his table saw!!! Right!,I want grinding dust in my table saw's trunnions,worm gears,etc..He had really worn out his welcome around the museum by then.Heard about his antics from other craftsmen. Well,he probably hadn't done TOO much damage if the blades were 20 years old. Another famous guitar making writer came in,and asked an incredibly basic question. I really couldn't believe it.

[Cliff Rohrabacher]

On a commercial saw the tension is released only during blade changes.

[Bill Keehn]

I wonder if the tension release arm is just something else to make us thinbk we need it? And,does the blade stay in contact with the wheel when it is detensioned? Does the blade fly off the wheel when you retension and start the saw? Either way,I KNOW my wife would never remember to retension the blade. She uses the bandsaw once every several months.My has other talents,don't get me wrong. She runs our home business(mostly her's) very well.She has incredible ability to find some obscure article in a 1940's magazine that I looked at 5 years ago (and showed her),now lost in hundreds of old magazines. We are a team. Each helps the other's weak points.

Well even though I don't detension, I don't think it's hype. The tool manufacturers are giving you a recommendation to protect what they think is most important - the machine they sold you. I think it is similar to car manufacturers recommendations to rotate your tires. It's probably a good idea -- but I never do it. Why not? Because they eventually wear out anyway, but probably not before I get a new car. In the meantime I have to look at what following manufacturers recommendations cost me in terms of time and money and risk. I mention risk because everytime you let someone work on your car you take a risk they won't do it right.

In terms of the bandsaw the costs of not detensioning seem to be at most occasionally buying a new blade or a new set of wheels. Weigh that against the time it takes you to de-tension, re-tension and re-tune your bandsaw setup. Weigh it against the risk of accidentally running the saw with the blade de-tensioned. Weigh it against the risk of wasting some of that expensive wood because your setup was messed up. It can take almost hour to fine tune your saw for the specific tension you are using. Who wants to bother with that?

I also overtension my blades because I think it gives me a better cut. I am sacrificing some HP to overcome the increased load on the motor. If I had smaller saw I might not do this, but it works for me.

[Chris Padilla]

I do detention my BS blades and yes, sometimes I forget to detention and sometimes I forget to retention the blades upon fire up.

I think the key is use. If a car sits for 6 months, it is likey to have issues than if it were running a bit more often...maybe even as little as once a month. I think the same could be said of a BS blade under high tension just sitting there...for 6 months. I think there could be issues as pointed out by many here.

[Steve Rozmiarek]

For over 20 years, I've never de-tensioned a blade when not in use. And, my bandsaw is only used intermittently in my hobby. I've grouped this practice in the same category as PVC duct blowing up my home, polyurethane glue being stronger than yellow glue, and using blade stabilizers on my tablesaw to reduce vibration.

However, I do wear a garlic clove around my neck when doing final assembly.

-Jeff :)


LOL! Thanks for the chuckle Jeff!

[Steve Rozmiarek]

A P.S.. Being in a major museum for 39 years,I have met a lot of well known people,among them authors. I think that craftsmen who build things build things. Some people like to write books. I had a well known woodworking author tell me that he had had the same blades on his planer for 20 years. When he did grind them,he had rigged up a jig to grind them on his table saw!!! Right!,I want grinding dust in my table saw's trunnions,worm gears,etc..He had really worn out his welcome around the museum by then.Heard about his antics from other craftsmen. Well,he probably hadn't done TOO much damage if the blades were 20 years old. Another famous guitar making writer came in,and asked an incredibly basic question. I really couldn't believe it.

That's interesting George, I know you didn't mention names for a reason, but it's fun to guess!

[george wilson]

He wrote a coffee table book about planes.

[Steve Rozmiarek]

Really?!?! Thats funny! Not the one I would have guessed.

[Loren Hedahl]

I also bought and installed a Carter de-tension unit for my Delta 14 some years ago.

The nice thing about this unit is that when the blade is de-tensioned, the handle on the Carter sets down on the table. You wouldn't be able to saw anything with that in the way, so you automatically remember to re-tension the blade.

In my case, I tend to forget to de-tension after use, but I've never had a blade break either. So I can't say whether it is effective or not.

My gut feeling is that I would have been better advised to have spent my hard earned money on more wood and less on stuff to make big wood into small wood.

[Carlos Alden]

I have a tension release on my Jet DX bandsaw. I clipped a small spring clamp on the power cord, where it sits between the UL label and the plug. When I detension the blade, it's my habit to clip this clamp to the detension lever. This unplugs the saw and is a clear visual cue that the blade is detensioned. Redundant safety.

Carlos

[Frank Drew]

On a commercial saw the tension is released only during blade changes.

Could you explain a little further, Cliff? By "commercial saw" do you mean a commercial grade saw in a professional (non-hobbyist) shop?

[glenn bradley]

I kept forgetting to release the tension on my saw and I didn't want to start it up with the tension released, so I hung a little cardboard sign over the on and off buttons that asks, "Tension?"

This allows me to concentrate on other aspects of the project to mess up.

:D

I have a small plastic clip that I put on the power switch paddle when tension is off on my little saw. My larger saw has a quick release that you would have to be half asleep to miss being in the "off" position so I'm OK there.

This is starting to sound a lot like the "ground your PVC" and "left tilt / right tilt" threads that get going . . . :eek: De-tension if you want to and don't if you don't want to; I don't think anyone will start shooting at you either way :D

[Steve Rozmiarek]

Well guys, for what it's worth, I'm going to continue my no detension "experiment", until something breaks. I will detension the big saw, but not the little one. Not expecting anything interesting to happen, but I'll let you know if it does.

I was using this saw today and got to thinking about this old thread. Wondered how long its been since I started the never detention experiment, officially 12 years with no issues. The only time it's been de-tensioned is blade changes. I'm honestly impressed the cheap little Delta has actually made it that long trouble free. I'll check back in 2029 (hopefully).

[Zachary Hoyt]

I wasn't on this site back then. I've never had a bandsaw with a quick de-tensioning lever, and I've never released the tension except to change blades. I don't think this has caused me any problems, but maybe I'm just not aware of them.

[Steve Rozmiarek]

I wasn't on this site back then. I've never had a bandsaw with a quick de-tensioning lever, and I've never released the tension except to change blades. I don't think this has caused me any problems, but maybe I'm just not aware of them.

If I remember correctly, there was a frenzy of bandsaw accessorization going on during that time period, one of the popular items being quick detensioning devices. Seems that the fad may have run its course, I haven't seen a thread about it in a while. Seemed silly back then so I decided to test it a little.

[Charlie Jones]

I had a Delta clone that I never released the tension on. My new Laguna has a tension lever. I release it when I shut the shop up for the day. I keep a stick laying on the table that has “tension saw” wrote on it. I tension it and remove the stick before use. I have no idea if it helps but it can’t hurt.

[johnny means]

Why release tension? Simple, to change the blade.

[Rod Sheridan]

In 40 years in industry I’ve never seen a saw detensioned and do it at home either.

I have a 90 year old motorcycle and it’s valve springs have never been detensioned.

I have fathers in metallurgists, they design good alloys......Rod

[Travis Conner]

I forgot one time and the blade popped out of the slot next to the on button and cut my finger when I turned it on. It stays tensioned now. No reason not to those tires are cheap and it's easy to put them on.

[Travis Conner]

I've never understood why they don't put a removable cover over that slot.

[Frederick Skelly]

I've never understood why they don't put a removable cover over that slot.

That's a good point. It should be easy to do. I'd buy a roll of dry erase magnet "stuff" like this (LINK (https://www.amazon.com/Sutter-Signs-10-feet-Reusable-Customizable/dp/B07NPXJ9RW/ref=sr_1_5?crid=3SCC5WPFO1XN8&dchild=1&keywords=magnetic+dry+erase+board+roll&qid=1613951706&sprefix=magnetic+dry+erase+board%2C+roll%2Caps%2C3 32&sr=8-5)) and cut it to length/width then overlay the slot.

[Travis Conner]

It took like 4 months for that cut to heal too since it was at the tip of my finger it would constantly reopen the cut when I bent it.

[Andrew Seemann]

I got my 14" cast iron Delta new in 1996. It has only been detensioned for blade changes. It works as well today as it did when I bought it 25 years ago. I have never broken a blade; blade changes are have only been because they have gone dull from wear. It gets hobby use, but is used at least once a week on average, though it can go a few weeks during the summer without any use. I did wear out a set of tires on it about 15 years ago. The higher quality replacement tires are still good.

The machine shop I worked in for 5 years during and after college had two bandsaws, a 36" metal cutting DoAll and a 24" Tannewitz we used for wood and aluminum. Neither were ever detensioned while I worked there, and I have no reason to believe they had ever been detensioned at any time prior or since.

[Curt Harms]

I have a Rikon with a detensioning lever. I'm sure a shop where a bandsaw runs at least once every few days doesn't benefit from detensioning. I haven't turned my saw on for probably 3 months and it takes bout 2 seconds to tension/detension. I unplug and hang the cord over the detensioning handle, haven't started it detensioned yet.

[John K Jordan]

I don't see that I posted this in this thread, but for those who detension when planning not to use the saw for a while (as I do) here is an idea for a reminder to retension before turning the saw on. This is not original but I can't remember where I got the idea.

This board hangs on the wall next to my saw.

452985

JKJ

[Bernie Kopfer]

Reading through these threads I noticed that no-one ever mentioned that they had experienced flat spots or grooves on their bandsaw tires. Or perhaps as soon as they ran the machine they disappeared. Is it possible that the newer non rubber tires do not take a set and the old ones did? Might be another myth that needs to be laid to rest, kinda like the one about never laying a plane blade down on a wooden surface.
(Sorry I could not help myself)

[Travis Conner]

I put one covering the on off switch and that worked great until a friend moved it and didn't read what it said, so I just leave it tensioned from now on.

[Eric Arnsdorff]

I’ve had this question as well. I’ve never de-tensioned my band saw. But I have wondered why the talk about releasing the tension.

My Grizzly 16” bandsaw is nearly 20 years old and I’ve never had any noticeable affect from leaving it tensioned even after several years of not using it. It has the original tires on it as well.

If my tires had degraded after 20 years I’d think that is a normal degradation of rubber “dry rot”. But that hasn’t even happened. Also, I kept my blade way over tensioned until recently when a new blade came with an instruction sheet on proper tensioning. It is a lot less tension than I used to keep on it. I used to simply tighten it as tight as I could get it. There are no flat spots or other noticeable issues.

[Larry Frank]

I have two band saws and only detension when I run very small blades such as 3/16" or less.

[Eric Arnsdorff]

Based on the responses, I'm not seeing any evidence in support of de-tensioning the blades. I would agree that if you're happy with doing it and that de-tensioning on your saw doesn't cause additional issues then it doesn't hurt to do it and errs on the side of caution.

Scientifically, the question comes down to the response of the materials when put under tension in the saw. I assume most if not all spring mechanisms in these saws are made from coiled spring steel which likely are well within their elastic region and likely to have an equivalent infinite life at the stress values seen by the materials. My saw has shown this to be true with no effect on the springs. It comes to mind that we don't know if a manufacturer may have used cheaper materials or have spring designs that are going beyond their elastic properties.

The remaining metal components involved include the wheels, bearings, fasteners and frame components. Once again these are expected to be loaded in their elastic region with an expectation of infinite life. Same argument would apply for a manufacturer using a poor design or incorrect materials - they could fail.

I do think people hear about fatigue failures of springs and such (which can and does happen) but this is a different mechanism and requires repeated cycling. The stress in a bandsaw spring and other tensioned components is a constant while the machine is not in use. When in operation, the bearings, wheels, shafts, and such do have cyclic fatigue effects but this has no impact on de-tensioning while not in use.

The remaining item would be the rubber tires on the wheels. This can vary and these type materials can creep enough to potentially cause an issue. I own a 20 year old Grizzly and while I'm not so confident the materials chosen for my tires were well engineered (maybe I'm not giving them enough credit - I can't say for certain). But even if it is by luck that my rubber tires are of a material that resists creep or taking a set under the loading presented by my saw, the fact is they have done so very effectively.

One other item this relates to is the belts, motors, arbors and other related components on all of my machines are all under tension and also have metal and elastomeric materials. However, I don't nor do I see any designs which utilize de-tensioning each time I leave my shop. Granted they do require replacing under heavy use eventually and once again - maybe I've been lucky but I've never replaced a belt on my equipment either. I am a one man shop that took several years off of woodworking while raising our kids and such. My tools aren't used remotely like an industrial/commercial facility. However, my shop represents quite a nice case study of the long term effect of leaving these items under tension.

My take on this after reviewing this as well as my personal use case is that a well made bandsaw should have no need to be de-tensioned.

I also know that sometimes even a "well engineered" machine can sometimes have unintended flaws that couldn't have been foreseen initially. So the idea of doing it just in case is still valid. Certainly, if you have a saw that exhibited an issue from being tensioned then by all means do what you need to do for it.

It really appears to be riskier to de-tension and possibly start it up this way or to tension it incorrectly. It also seems to like it could add additional wear on components that (at least in my saw's design case) aren't designed for repeated tensioning/de-tensioning.

[Larry Edgerton]

Never! No problems.

Did you ever buy that Lamello thingy? Bought my ex out of my house instead but is still on my radar when the $$ balance is back up.

[Mel Fulks]

For years I worked for a family run mill work business....not my family. Some of them were detensioners and some were fogetabouters.
All I can tell you is they never broke the machine.

[Steve Demuth]

Yep. For a time I thought I'd be good and detension when done with the saw. All it ever accomplished was to cause me trouble when I next needed the saw and forgot - despite all the clues I left myself - to retension. I quit after a couple of those episodes, and ten years on the same saw have never seen any ill effect from leaving tension on.

[Steve Rozmiarek]

Never! No problems.

Did you ever buy that Lamello thingy? Bought my ex out of my house instead but is still on my radar when the $$ balance is back up.

I didn't yet, I was hoping you'd buy it first and give it a good test so I'd know if it was a good idea! Sounds like you are probably spending wisely though. Was actually just thinking about it yesterday. It would make this current job easier to install, ought to just do it. I really don't like the domino, lamello might be the better mousetrap.

[Roger Feeley]

I have two bandsaws. The 20 year old craftsman has never had the tension released and seems to yuan fine on the original bearings and tires. The newer rikon is rigged with a micro switch that turns two led task lights on when it’s under tension. That means when I leave the room and turn out the lights, the bandsaw nags me. In truth, I think the Craftsman runs smoother.

[John Stankus]

Some of the question of detension or not to detension comes down to the saw and the materials used in the critical parts.
I just replaced the hinge for the upper wheel on my JET JWBS-14CS. This spent probably a decade where I just left it under tension. The upper hinge assembly is made from some cheap pot metal and distorted over time, to where the hinge was interfering with the shroud (I though I had a picture of that from before). This would interfere on adjustment and tensioning.
453306
This is the original hinge compared to an engineer's square. The hinge arm is bent, so that it interferes with the sheet metal shroud. The part where the arrow is pointing is where it would interfere.

453303
This is the replacement hinge with an iron pivot arm. (item 153303814248 from wmprice on ebay) I tried to email to make sure I got the correct assembly, but no response. Since the dimensions seemed correct I went ahead and ordered.
The two arrows show where I had to use a file to trim the pot metal back a bit. If you do this have a file card around since the pot metal will clog up the file.

When I first started to look into repairing this a couple of years ago, I tried emailing with Iturra but had issues with him responding. (I think I got a response to my first email, that my vintage saw could not have that problem, and then no response to my followup email. While by reputation the Iturra parts are probably better, I went with where I could deal with an online order (even though the email responsiveness was about the same))

John

[Malcolm McLeod]

... the materials used in the critical parts. ...

I de-tension a RIKON because it's easy, I don't have to even think about creep in the materials, and I swapped a mechanical for a tension-interlocked mag starter. Now even I can't mess it up.

[Timothy Orr]

Some of the question of detension or not to detension comes down to the saw and the materials used in the critical parts.


I agree that this is the key issue.

Specifically if zinc parts are used as in the example given by John. Zinc alloys are very susceptible to creep. For the technically inclined here is a link to some details:

https://www.dynacast.com/en/knowledge-center/material-information/die-cast-metals/zinc-casting-metals/zinc-creep

Note in particular some of the graphs are creep rate in % per 10,000 hours which is a little more than a year. So the takeaway for me is a less robustly designed part could be moving quite significantly over the expected lifetime of a machine.

So in that case detensioning would be a good thing to do to prevent premature failure of the zinc part.

Of course your mileage may vary.

Tim Orr

[Alex Zeller]

I don't think you'll see a black and white difference. Most of the "I don't" people seem to not do it because they don't want to take the time to do it or because they will forget to tension it. I'd be in that group except for my Grizzly has a lever so it's quick and a key to turn on the power that gets hung on a magnet next to the lever when detensioned. In the long run I think it's better to remove the tension. It's just not easy to see any results. Most people would never notice if their BS has slightly more vibrations than when new. Most likely the bearings, while could be damaged, will still work just fine. In fact most would feel that if they got 25 years out of a bearing to be good. Yet that same bearing might have gone twice that, you'll never know.

One thing is for certain. Very little, if anything, is under the same tension as a BS. Belts are the most common thing and the level of tension they see is a tiny fraction of what a BS is set up to.

[Rod Sheridan]

Actually the tension on a bandsaw is very slight.

I have a 90 year old motorcycle, I never detension the valve springs, they're doing just fine.

Same for all the springs in dampers, Reeves drives etc.

I guess if you have a "bandsaw shaped object" as opposed to a bandsaw it could be an issue, however with over 40 years in industry I have never seen a saw detensioned and many are 40 or 50 years old......Regards, Rod.

[Malcolm McLeod]

I don't think the metallurgy or creep properties of the tensioning springs is in question (same for a motorcycle). It is the other parts of the system that give me pause.

(A motor's valve spring is much more likely to break due to fatigue imposed by the high cyclic rate of load changes. I'd have to be really quick on the lever of a Rikon to replicate it.)

[John K Jordan]

I don't think the metallurgy or creep properties of the tensioning springs is in question (same for a motorcycle). It is the other parts of the system that give me pause.
(A motor's valve spring is much more likely to break due to fatigue imposed by the high cyclic rate of load changes. I'd have to be really quick on the lever of a Rikon to replicate it.)

The tension spring was prone to "weaken" in the common older 14" Delta and Jet saws with cast iron frames. This happened to the one in my old Delta after about 10 years. I bought a replacement spring from Iturra and it was a better quality spring.

Other tensioning parts of the system on the Delta did distort and had to be replaced, but the spring did too.

I also fixed an old Jet with the same problem that John Stankus mentioned. The cheap metal had deformed. I was asked to stop by the community training organization and adjust the tension of the saw but didn't bring tools. Fortunately they found a file somewhere so I made it work.

JKJ