Bandsaw blade tension poll

[Phil Thien]

Okay, Tony Ward posted a link to a guitar tuner the other day and said that a number of bandsaw users that use the pluck method in determining tension find they get an "A string" equiv. on the tuner.

I don't know why this topic intrigues me so much. I do find that I've been tuning somewhere between lower E and A for some time (on my saw with no tension meter).

ANYWAY, I thought it would be interesting to get a poll going and have lots of people pluck their blade (on the side opposite the guides) next time they're in the shop and determine the note on the guitar tuner that most closely matches their blade's tone.

If you would also post your bandsaw model (for example, Rikon) and size (for example, 14"), and the blade length (for example, 72") and type (for example, 1/4" wide x 6-tpi), that would help me, as well. Extra points if you have something like a Carter tension meter and can actually post the tension required to get the tones on the scale.

Here is the link to the tuner:
http://www.guitarforbeginners.com:80/onlinetuner.html

BTW, I'm aware that some are dismissive of this technique because larger bandsaws have larger spans and the same blade over the longer span, tensioned to the same amount, will sound lower. Humor me. If nothing else, someone will be able to find someone else posting with the same 14" saw type and the same blade type and compare notes. But I have a theory that the same blade type on a larger saw has to be tensioned more because of the longer span, and the same note (or close to it) will be achieved.

[glenn bradley]

I use the flutter method but, this should be fun ;-)

[Lee Schierer]

I use the flutter method but, this should be fun ;-)

I couldn't pick an A out of a choice of one note without guessing, I tend to tighten min by feel. If it wanders then it get a bit more tension.

[Frederick Wilt]

I'll need to get some help to move my saw up to my office where the computer is.

Once that's done I let you know.

[Jacob Reverb]

I just use the tension gauge on my Rikon 17" and it varies depending on the width of the blade.

[Greg Crawford]

I don't use plucked blades. Are they better?

[Phil Thien]

I just use the tension gauge on my Rikon 17" and it varies depending on the width of the blade.

But, does the sound of the plucked blade vary.

That is, if you put a 1/4" blade on, and tension to the scale, then replace with a 1/2" blade and tension to the scale, do the plucked blades sound similar? And if so, what note from the guitar tuner (linked above) do they make?

[Phil Thien]

I use the flutter method but, this should be fun ;-)

When you think about it, the flutter method is related to the pluck method. And the flutter method that Suffolk suggests correlates with my theory a little.

Say you put a 1/2" blade on a 14" saw. You reduce tension until you observe some flutter, and then apply a little more tension to get rid of that flutter.

Now imagine you were able to move the wheels somewhat further apart and magically lengthen the blade without changing the tension.

Now when you start the saw, you may expect some flutter. That is because the blade is spanning a greater unsupported distance. So if you increase tension to rid yourself of the flutter, does the plucked blade sound the same as it did before you increased the span length?

[Phil Thien]

I don't use plucked blades. Are they better?

Those trying to turn this into a joke will not be privy to my "Unified Theory of Bandsaw Blade Tension" paper, which will be peer reviewed and only made available to those providing useful input. :p

[Chris Padilla]

Well, I don't pluck my blades. I crank up the tension pretty high and then push on the blade to get about a 1/4" - 3/8" deflection and feel how hard it is to deflect the blade that much. My finger is my gauge, I guess. :)

I wouldn't know an A from an E from a Z note if they came up and bit me! :D

[Jeff Mohr]

Those trying to turn this into a joke will not be privy to my "Unified Theory of Bandsaw Blade Tension" paper, which will be peer reviewed and only made available to those providing useful input. :p

Well then, I tune mine to A sharp....but only using bagpipes.

[Phil Thien]

Well, I don't pluck my blades. I crank up the tension pretty high and then push on the blade to get about a 1/4" - 3/8" deflection and feel how hard it is to deflect the blade that much. My finger is my gauge, I guess. :)

I wouldn't know an A from an E from a Z note if they came up and bit me! :D

Okay, there seems to be some confusion about what I want.

I need you to tension your blades however you're accustomed to doing so. Then I want you to pluck the blade a few times and try to remember the tone. Finally, use the link to the guitar tuner I've provided and see if the tone you heard is close to any of the notes on that scale.

The reason behind all this is that many of us that pluck our blades have independently found we're adjusting to approx. the same frequency. Furthermore, it seems to correlate somewhat with the flutter method.

So you say you tension a lot and deflect. Now I'm just wondering what that blade sounds like.

I know this thread seems like a natural for one-liners for some of you. And if you have a real good one, let's hear it. But at the end of the day I need you guys to pluck those blades and complete the poll.

[Chris Padilla]

Ah, thanks for clearing it up, Phil. Weeeellllll, lemmmeee seeeee what I can about pluckin' and listenin'. :)

[Myk Rian]

I use the flutter method, but my 1/4" on a 14" Delta w/riser is close to a D.

[george wilson]

The question is flawed. I am a guitar maker. The pitch of the blade will vary with the height of the top guide,even if it is exactly the same tension. Also,the thickness and width will produce very different pitches. A strain gauge,which most of us don't have (or need !!!!) is the way to measure tension.

[Jason Beam]

Okay, there seems to be some confusion about what I want.

I need you to tension your blades however you're accustomed to doing so. Then I want you to pluck the blade a few times and try to remember the tone. Finally, use the link to the guitar tuner I've provided and see if the tone you heard is close to any of the notes on that scale.

The reason behind all this is that many of us that pluck our blades have independently found we're adjusting to approx. the same frequency. Furthermore, it seems to correlate somewhat with the flutter method.

So you say you tension a lot and deflect. Now I'm just wondering what that blade sounds like.

I know this thread seems like a natural for one-liners for some of you. And if you have a real good one, let's hear it. But at the end of the day I need you guys to pluck those blades and complete the poll.

I don't think it's the exact same note ... maybe across different octaves, though.

My guitars have varying thicknesses of strings on 'em ... with me so far? Okay ... in normal tunings, they all have varying amounts of tension on them, right? I don't believe i could get my low E string to come anywhere close to my high E's string before the guitar itself failed structurally. The relative thickness of the string requires a whole lot more tension (granted we're crossing two whole octaves, here, though).

But given that a high E's string is thinner than the low E's, i dunno if you can get the same note out of a 1/8" blade as you do a 3/4" blade - there's quite a big differential in mass here and it'd take an exponential increase in tension to get the 3/4" blade to resonate at the same frequency of the 1/8" blade. Maybe octaves apart, but I'm still dubious about this whole note thing..

I honestly don't think many woodworkers possess such a trained ear to recognize a given note from a bandsaw. I am skeptical and wonder if some of these claims are simply fish stories to some degree.

I will, however, agree that you can probably get a pretty good idea of proper blade tension by plucking the thing. I hear about this with scroll saw blades, too. Ya tighten it until you get a crisp, well defined, sustained tone - it's *a* note, but which note isn't important. This seems a bit easier for me to grasp .. it should ring out, whatever the frequency ...

Different width (and thickness) blades are gonna naturally resonate at various levels of tension - i just don't think every blade's tension sweet spot is the same note. Or any note, for that matter.

[Ken Fitzgerald]

The question is flawed. I am a guitar maker. The pitch of the blade will vary with the height of the top guide,even if it is exactly the same tension. Also,the thickness and width will produce very different pitches. A strain gauge,which most of us don't have (or need !!!!) is the way to measure tension.

George,

The question isn't flawed if the blade guide isn't touching and everyone is using the same blade.

I do agree that the thickness and the width of the blade will change the pitch for a given tension.

I also agree we don't need a strain gauge.

[Joe Hardesty]

Not sure what key it is in, but I can play Beethoven's 5th on piece of crotch walnut with a 3/4" blade. If I get mama to run the router around some curly Koa, we sound like the Boston Pops.

[Gene Howe]

If a blade is plucked in the shop and, there's no one to hear it, does it make a sound?

[Phil Thien]

The question is flawed. I am a guitar maker. The pitch of the blade will vary with the height of the top guide,even if it is exactly the same tension. Also,the thickness and width will produce very different pitches. A strain gauge,which most of us don't have (or need !!!!) is the way to measure tension.

(1) First, everyone should pluck on the side of the blade opposite the guides. :eek: The guides don't enter into the equation.

(2) Cross-section is possibly cancelled out by the greater force applied to a larger blade.

(3) I'm not attempting to compute tension to +/- .5-lbs based upon the sound of the blade. If you read my posts above you'll see what I'm after.

It is such an easy test, please just humor me.

[Phil Thien]

George,

The question isn't flawed if the blade guide isn't touching and everyone is using the same blade.

I do agree that the thickness and the width of the blade will change the pitch for a given tension.


Most bandsaws have built-in scales that will attempt to apply the same tension regardless of the blade size, right? That is, crank to this point for a 1/4" blade, crank to this point for 3/8", and here for 1/2", right?

They're trying to apply the same tension (say 20k # PSI) across the line. As the blade's width increases, more force is required to get to that 20k.

So do 1/4" and 1/2" blades, both tensioned to 20k, sound similar? Remember, we're pulling on the wheels much harder to get that 1/2" blade to the same tension (PSI) as the 1/4".

Similar to a guitar where we attempt to tune all the strings to the same frequency. We really crank the larger strings, and don't pull the smaller strings so much.

Assuming I'm right (and I'm not there yet), I begin to wonder what 20k sounds like on various 10", 12", 14" and larger saws.

Given the fact that we can't afford accurate strain gauges like the Carter, wouldn't it be kinda kewl to know that 20k PSI on a 1/2" .025" blade on a standard 14" Delta knock-off is the same as "A" on the guitar scale?

For years books have advocated a pluck test. It would just be nice to be able to point to an online reference for sounds based upon the size of the saw, and say "if you hear this w/ a 1/4" blade on a 10" bandsaw, you're at approx. 20k PSI. If you hear this, you're way too high, or low.

[Phil Thien]

My guitars have varying thicknesses of strings on 'em ... with me so far? Okay ... in normal tunings, they all have varying amounts of tension on them, right? I don't believe i could get my low E string to come anywhere close to my high E's string before the guitar itself failed structurally. The relative thickness of the string requires a whole lot more tension (granted we're crossing two whole octaves, here, though).

But, could you lower the high E and raise the low E to get them pretty darn close?

And isn't that exactly what the bandsaw's gauge attempts? To apply the same PSI by changing force applied for different thickness blades?


But given that a high E's string is thinner than the low E's, i dunno if you can get the same note out of a 1/8" blade as you do a 3/4" blade - there's quite a big differential in mass here and it'd take an exponential increase in tension to get the 3/4" blade to resonate at the same frequency of the 1/8" blade. Maybe octaves apart, but I'm still dubious about this whole note thing..

Dubious is fine, as long as you pluck that band and vote. We're getting some responses now. And the distribution (small sample, though) is pretty close to what I'd expect.


I honestly don't think many woodworkers possess such a trained ear to recognize a given note from a bandsaw. I am skeptical and wonder if some of these claims are simply fish stories to some degree.

Those woodworkers seem to be concentrating on the one-liners. Gotta love 'em. :D


I will, however, agree that you can probably get a pretty good idea of proper blade tension by plucking the thing. I hear about this with scroll saw blades, too. Ya tighten it until you get a crisp, well defined, sustained tone - it's *a* note, but which note isn't important. This seems a bit easier for me to grasp .. it should ring out, whatever the frequency ...

Different width (and thickness) blades are gonna naturally resonate at various levels of tension - i just don't think every blade's tension sweet spot is the same note. Or any note, for that matter.

I'm not saying they're all the same, just wondering what the distribution is. Maybe after this weekend we will have more responses and can start drawing conclusions.

It is a little interesting, isn't it? Seriously, for the amount of time it takes to perform the test, and register your result, it is a no-brainer to at least check.

[Jason Beam]

But, could you lower the high E and raise the low E to get them pretty darn close?

And isn't that exactly what the bandsaw's gauge attempts? To apply the same PSI by changing force applied for different thickness blades?



Dubious is fine, as long as you pluck that band and vote. We're getting some responses now. And the distribution (small sample, though) is pretty close to what I'd expect.



Those woodworkers seem to be concentrating on the one-liners. Gotta love 'em. :D



I'm not saying they're all the same, just wondering what the distribution is. Maybe after this weekend we will have more responses and can start drawing conclusions.

It is a little interesting, isn't it? Seriously, for the amount of time it takes to perform the test, and register your result, it is a no-brainer to at least check.


I can't vote - you don't have an option for me. On a guitar, lowering the high E string down until it matches the low e's pitch means you're nowhere close to having the same amount of tension (20kpsi, for example). Pitch is actually mathematically (and theoretically) calculable by taking the length of the free-vibrating distance (size of saw) and factoring in the tension level (20kpsi, for example) AND the cross-section of the item being tensioned (blade thickness/width).

It is established already that a bandsaw blade should be tensioned to a fairly specific tension range 15-20kpsi, i believe - depending on manufacturer. If you put a 1/4" blade at 15kpsi and pluck it, it will surely strike a tone of some kind. Swap that blade for a 3/4" blade and put it at 15kpis as well, it will NOT sound the same note.

Will it satisfy you to say that I plucked my blades and found very different notes? They are different. I knew they would be! :D


PS: I do agree, the thought experiment is interesting - but the only variable you can't change (very much, that is) is the tension on the blade to get a decent cut.

[Jason Beam]

So do 1/4" and 1/2" blades, both tensioned to 20k, sound similar? Remember, we're pulling on the wheels much harder to get that 1/2" blade to the same tension (PSI) as the 1/4".

This is the question I have issues with (in case my rambling wasn't clear). THe answer to your question above is, very flatly: No.

Distance, tension and the mass of the object determine the resonant frequency. If you keep all but the mass the same, the notes will be different. You MUST adjust one of the other factors to compensate for that difference in mass.

[Phil Thien]

This is the question I have issues with (in case my rambling wasn't clear). THe answer to your question above is, very flatly: No.

Distance, tension and the mass of the object determine the resonant frequency. If you keep all but the mass the same, the notes will be different. You MUST adjust one of the other factors to compensate for that difference in mass.

Here, if you use this calculator:
http://hyperphysics.phy-astr.gsu.edu/Hbase/waves/string.html#c2

You can see that if you double the mass of the string and double the tension of the spring, you will maintain the same velocity and frequency, right?

So in another example, if we take two six foot long bands (one 1/4", and one 1/2") and hang them from a door opening, with the 1/4" band having a 300 # weight on it, and the 1/2" band having a 600# weight on it, they should be resonate at the same frequency, right? And they will both be tensioned to the same PSI, right?

[Jason Beam]

So in another example, if we take two six foot long bands (one 1/4", and one 1/2") and hang them from a door opening, with the 1/4" band having a 300 # weight on it, and the 1/2" band having a 600# weight on it, they should be resonate at the same frequency, right? And they will both be tensioned to the same PSI, right?

No, i don't agree. Here's why: My 1/4" band, properly tensioned according to the flutter method makes a higher pitched sound than my 3/4" blade tensioned in kind.

The force required to meet a given tension has nothing to do with the resonant frequency. Tension is tension - no matter how you get there. If you reach 20kpsi on both of the bands, the only variable you're changing is the mass of the band which will change the resonant frequency. In order for the frequency to remain the same, all three factors must come out of the equation you've provided exactly the same. Since you're not making the thing longer and you're not changing the tension, the change in mass WILL affect the frequency. If you change the mass, you have to either change the tension or the length in order to retain a given pitch.

EDIT: One other detail ... Your 300# and 600# weights are not going to yield the same tension. The force required to maintain the tension is the square of the cross section - which means you can't just double the weight when you double the band width - it takes the square of the delta, IIRC, as it's multiplier.

[harry strasil]

I am tone deaf, can't carry a tune in a 5 gal bucket, I just tension it till it cuts right, then do it the same each time I retension it to use it, if I didn't forget the time before.

Here is the way I do it. http://www.sawmillcreek.org/showthread.php?t=73734&highlight=bandsaw+tension

[Tony Ward]

Phil well done. In the polls on other forums "A" is the dominant response.

A number of respondents say the sound will vary with the size and length of the blade, however I have not seen any substantive evidence to support that theory.

My "A" sound comes from a 1/4 inch blade on a 300mm / 12" Chinese machine distributed in Australia as Woodfast.

[Ken Fitzgerald]

I don't pluck my bandsaw blades. I did pluck chickens as a child living on a farm.

I adjust my blade to a coarse setting on the tension gauge that came with my MM-16 and then......and then I somewhat apply the flutter method and then I check the results.


For the record I took my Boss guitar tuner to the shop and my 1/2" Olsen blade plucked at about F sharp.

I seem to get satisfying results with my method and that is all that's important. I hope you find a method that satisfies your needs.

[Phil Thien]

No, i don't agree.

I'm pretty sure I'm right on this. Try the calculator. Enter a tension of 600-lbs, a length of 1000-cm, and a mass/length of 6.0-gm/m. Now click on "Velocity" and you'll get a fundamental freq. of 33.34-Hz.

Now, change the tension to 300-lbs, keep the length at 1000-cm, and change the mass/length to 3.0-gm/m. Now click on "Velocity" and you'll find the same fundamental freq. of 33.34-Hz.


The force required to meet a given tension has nothing to do with the resonant frequency. Tension is tension - no matter how you get there. If you reach 20kpsi on both of the bands, the only variable you're changing is the mass of the band which will change the resonant frequency.

For the purpose of computing the frequency, one uses newtons or pounds, not newtons or pounds PSI (Per Square Inch), right? Band makers want approx. 25k-PSI tension on their bands. There is a lot more force required to achieve that on a 1" band than on, say, a 1/4" band.


In order for the frequency to remain the same, all three factors must come out of the equation you've provided exactly the same. Since you're not making the thing longer and you're not changing the tension,

We are changing the tension. PSI is the same, overall tension increases however.


the change in mass WILL affect the frequency. If you change the mass, you have to either change the tension or the length in order to retain a given pitch.

EDIT: One other detail ... Your 300# and 600# weights are not going to yield the same tension.

Right, the tension is doubled by doubling the weight. But the PSI remains a constant, because the cross section of the band doubles.

Is there a physicist/engineer in the house?

[Phil Thien]

I don't pluck my bandsaw blades. I did pluck chickens as a child living on a farm.

I adjust my blade to a coarse setting on the tension gauge that came with my MM-16 and then......and then I somewhat apply the flutter method and then I check the results.


For the record I took my Boss guitar tuner to the shop and my 1/2" Olsen blade plucked at about F sharp.

I seem to get satisfying results with my method and that is all that's important. I hope you find a method that satisfies your needs.

I agree. I'm not trying to get anyone to change their technique.

All I need you to do is make the appropriate selection in the poll. Sounds like you're off the scale on the high side?

[Jason Beam]

Ugh ... I give up, man.

You said earlier that the tension would be the same and now you just told me to change the tension in the calculator.

Changing the tension is not an option. Manufacturers have stated optimal tension to be around 15k-20k PSI - so stick with that range.

You will not get the same note from a properly tensioned 1/4" blade as you will from a properly tensioned 1/2" blade EVEN ON THE SAME SAW. Nevermind that your poll is asking for some note on an arbitrary number of blades, saws and distances. The frequency will be different based upon too many factors to draw a single conclusion and pick the optimal note. Won't happen.

Your argument has changed. If you use that calculator and ONLY change the mass value, the frequency will change. This is the theory you're testing. Changing tension is not in the parameters because regardless of width, the proper tension remains the same - somewhere in the 15k-20k psi range.

NOW ... if you change your question to ask HOW MUCH the frequency changes, I might be able to come along with you on this journey. From what I could see, the relative mass changes result in a relatively slight change in frequency - surely perceptible still, though. It wouldn't be the same note, but the range should be within maybe a full step or step and a half (in guitar speak). That is, a range of say A flat to C flat for example.

Change the tension and all bets are off. Just like your example of lowering the tension on the high E string of my guitar to make the same sound as my low E string does - well sure, i can get it to that frequency, but they won't have the same tension - and the high E string won't resonate for very long.

If you change mass, you have to change tension or length in order to reproduce the same note. There's no other way to say it. The frequency is a product of those three properties and changing ANY of them without regard to the others will change the frequency produced.

Your latest response to me says you get that, though, so maybe we're saying the same things. You were saying the two bands would have the same tension before but now you're saying to change the tension so you've lost me.

It had my brains churning for a little while, though. :D

[Phil Thien]

Your argument has changed. If you use that calculator and ONLY change the mass value, the frequency will change. This is the theory you're testing. Changing tension is not in the parameters because regardless of width, the proper tension remains the same - somewhere in the 15k-20k psi range.


You keep saying the tension remains the same at 15k to 20k regardless of blade size. But that is PSI (Per Square Inch) of cross-section. As you increase blade width, you increase tension, but PSI (Per Square Inch) remains the same, right?

That is, when you're using that calculator, you're entering tension in newtons or pounds-force, PSI doesn't enter into it.

I think you're confusing tension as a force, and stated as a product of cross-section in PSI.

So what I'm saying is that two blades of different sizes can be under different tensions, while having the same PSI.

And that both blades can produce the same frequency when plucked, while a 1/2" blade is under twice the amount of tension as the 1/4" blade, all the while the blades are tensioned to the same PSI.

[Stephen Edwards]

I'll need to get some help to move my saw up to my office where the computer is.

Once that's done I let you know.


HAHAHAHAHA!!!! Thanks for the Laugh!:D I'm headed your way with a moving dolly.

[Greg Crawford]

OK Phil, I'll get serious. I didn't notice the link to the tuner, and I also wouldn't know a D from a K. Anyway, I placed my vote for the A. That's on a 1" wide blade, tightened with the flutter method.

[Jason Beam]

You keep saying the tension remains the same at 15k to 20k regardless of blade size. But that is PSI (Per Square Inch) of cross-section. As you increase blade width, you increase tension, but PSI (Per Square Inch) remains the same, right?

That is, when you're using that calculator, you're entering tension in newtons or pounds-force, PSI doesn't enter into it.

I think you're confusing tension as a force, and stated as a product of cross-section in PSI.

So what I'm saying is that two blades of different sizes can be under different tensions, while having the same PSI.

And that both blades can produce the same frequency when plucked, while a 1/2" blade is under twice the amount of tension as the 1/4" blade, all the while the blades are tensioned to the same PSI.


Okay ... fine ...

I put a 3/4" blade on my saw (G0586x2) and tensioned it perfectly - no drift, nothing - cuts beautifully - properly tensioned. Plucked it ... and it went Dunnnnnnnnnn...

Then ... get this ...

I pulled that 3/4" blade off ... put on my 1/4" blade ... and tensioned it gorgeously with no drift, nothing ... cuts beautifully ... properly tensioned. Then ... i plucked that bugger ... and you know what? It went Diinnnnnn...

Maybe even the same octave ... but no way it could be confused for the same note ... the 3/4" was markedly lower than the 1/4".

There.

Now i give up. :)

[Phil Thien]

Okay, if anyone is left reading this...

I think it should be possible to generate a spreadsheet that will allow the average user to use a $13 guitar tuner to determine the tension of their blade. It is my belief that the technique would be more accurate than any clamp-on gauges, and may approach the accuracy of the Carter load-cell gauges.

All that would be required is: (1) Measuring the weight of the blade using a good kitchen scale (in grams for greater resolution than ounces). (2) Measuring the distance between the two wheel centers when the blade is under initial tension. (3) Measuring the diameter of the wheel. (4) Providing the overall length of the blade.

With those values plugged into a web page, it should be possible to generate a table of frequencies a plucked blade would produce at 1k-PSI intervals, and to use the chromatic tuner to get the tension right to the desired spot. Alternately, it should be possible to also plug a frequency into the web page and determine the current tension.

I don't know if there is any interest in this but I'll post my web page if there is.

[Chris Padilla]

Admirable drive you have here, Phil. I'll have to look up all this stuff in my college physics book one of these days and we can put some real, accurate science into your thought/sound experiment here. Fun, fun! :D

[Nick Abbott]

I am still reading the thread.

[Tim Put]

I'm with you Phil. On the total force versus force per square inch as well.

To Jason: Imagine a 1/4" blade tensioned, with let's say 300lbs, ringing at note "X". Now imagine a second absolutely identical blade tensioned, plucked and ringing in exactly the same way. A 1/2" blade loaded with 600lbs is the equivalent of the two 1/4" blades strapped together.

P.S. I walked over to my bandsaw and took a listen. As I was last using it, my 14" saw with a 1/4"x0.025"x97.5" (26.75" sounding length) blade rings at a moderatly flat G an octave and a fourth below middle C.

[Jason Beam]

I'm with you Phil. On the total force versus force per square inch as well.

To Jason: Imagine a 1/4" blade tensioned, with let's say 300lbs, ringing at note "X". Now imagine a second absolutely identical blade tensioned, plucked and ringing in exactly the same way. A 1/2" blade loaded with 600lbs is the equivalent of the two 1/4" blades strapped together.

P.S. I walked over to my bandsaw and took a listen. As I was last using it, my 14" saw with a 1/4"x0.025"x97.5" (26.75" sounding length) blade rings at a moderatly flat G an octave and a fourth below middle C.

Okay .. then why is my 1/4" blade higher pitched than my 3/4" blade? I thought they are supposed to sound the same? My tension is the same (the force applied to reach that tension is obviously different, but I'll wager the tension is very close to the same). They both cut perfectly ... the saw hasn't changed. I get a different note. They both "Ring true" but they don't ring at the same note. I'd say they're only a step, step and a half away from one another, but still it's a marked difference.

[Bruce Shiverdecker]

After some instruction and reading installation instructions, I don't PLUCK my blade.

For FULL tension blades, I use the scale on the bandsaw.

For LOW tension blades, which I use now almost all the time, such as Timberwolf blades, I put them on the wheels and SNUG them up, making sure that the gullet is centered on the tire.

Then I start tighening them till the wobble goes away and add one half turn. Works fine.

If you over tighten a LOW Tension blade, you will get a premature failure.

Bruce

[Tim Put]

Okay .. then why is my 1/4" blade higher pitched than my 3/4" blade? I thought they are supposed to sound the same? My tension is the same (the force applied to reach that tension is obviously different, but I'll wager the tension is very close to the same). They both cut perfectly ... the saw hasn't changed. I get a different note. They both "Ring true" but they don't ring at the same note. I'd say they're only a step, step and a half away from one another, but still it's a marked difference.


http://en.wikipedia.org/wiki/Vibrating_string

Look at the equations on this page. wave propagation speed is a function of the ratio of tension (total force not force per unit area) and linear mass. The only other variable is length. If we regard your blades as having similar construction, as having a linear weight proportional to their cross section times a constant for the density of steel; then we can for present purposes regard the ratio of tension and linear mass as a direct function of stress (tension per unit area). Then if length is constant, which for a given bandsaw it is. Frequency is dependent solely on stress.

Your two blades are not tensioned to the same stress, with some error margin due to differences in the density of steel used, tooth geometry which we did not take into account, and the simplifying assumption made by the vibrating string equations that the string in question is perfectly flexible (stiffness will tend to increase the pitch of the stiffer blade, loosely by making it act shorter).


P.S. Technically we should all be using tension for the total force and stress for the tension per unit area. Though no matter which we use, context and the units used will let one figure it out.