I thought this was a brilliant idea, but it failed completely. Why?
I opened a digital micrometer to 4" and clamped the two ends to a band saw
blade. I then tensioned the blade. I figured the micrometer jaws would be
pulled apart a few thousanths and I could determine the tension.
Nothing happened. I flipped the tension lever back and fourth, but it stood
relentlessly at 4". The ends were clamped securely and the micrometer took
very little force to move, so I don't think they were just slipping.
Shouldn't this work, or at least do something?
"Toller" <[email protected]> wrote:
>I opened a digital micrometer to 4" and clamped the two ends to a band saw
>blade. I then tensioned the blade. I figured the micrometer jaws would be
>pulled apart a few thousanths and I could determine the tension.
I'm no machinist, but I think you are using either the wrong tool or
the wrong name for your tool. A micrometer looks like a C-clamp, with
a rigid steel frame. If this is what you are using, you are applying
tension to your micrometer frame, which I would hope is much thicker
and more stretch resistant than your bandsaw blade. If you manage to
somehow clamp the blade tight enough to the frame to get a reading,
you will have bent the frame and forced your anvils out of parallel,
making the micrometer useless, though I doubt many band saws will
generate that much tension. It might be possible to clamp the jaws of
a digital caliper to a bandsaw blade, but you are probably better off
using a dial indicator, as the professional tension gauges do. I've
seen plans for homemade tension gauges in magazines (FWW?) using cheap
dial indicators. Maybe someone here can give you a link.
On Wed, 12 Apr 2006 10:38:40 -0500, "Swingman" <[email protected]> wrote:
>Recently 'inherited' an Iturra "Blade Gage" which works on the same
>principle.
>
>Made me immediately upgrade the tension spring in my US Delta 14" bandsaw.
I would have thought that an old musician like you would have used the
"tuning fork method".
You can look it up.
When it first came out it didn't make a lot of sense for guys who
couldn't hear different notes, but in an age where a tuning checker
can be had for twenty bucks it might make sense to tune a bandsaw
blade according to the note it makes when plucked.
Regards,
Tom Watson
tjwatson1ATcomcastDOTnet (real email)
http://home.comcast.net/~tjwatson1/
Toller wrote:
> I thought this was a brilliant idea, but it failed completely. Why?
>
> I opened a digital micrometer to 4" and clamped the two ends to a band saw
> blade. I then tensioned the blade. I figured the micrometer jaws would be
> pulled apart a few thousanths and I could determine the tension.
>
> Nothing happened. I flipped the tension lever back and fourth, but it stood
> relentlessly at 4". The ends were clamped securely and the micrometer took
> very little force to move, so I don't think they were just slipping.
>
> Shouldn't this work, or at least do something?
If you clamp a micrometer spindle it won't turn. Why would you expect
the reading to change?
John Martin
Bruce Barnett wrote:
> "Toller" <[email protected]> writes:
>
> > I thought this was a brilliant idea, but it failed completely. Why?
> >
> > I opened a digital micrometer to 4" and clamped the two ends to a band saw
> > blade. I then tensioned the blade. I figured the micrometer jaws would be
> > pulled apart a few thousanths and I could determine the tension.
>
> So you are measuring stretch?
> What if you apply a deflection?
problem with measuring deflection is variation from blade with and
tooth pattern. if you measure stretch the only variation you need to
account for is steel type, and that difference is tiny.
Toller wrote:
> I opened a digital micrometer to 4" and clamped the two ends to a band saw
> blade. I then tensioned the blade. I figured the micrometer jaws would be
> pulled apart a few thousanths and I could determine the tension.
> Shouldn't this work, or at least do something?
Yes, and in fact FWW had an article on a tensiometer based on similar
technique (except they used feeler gauges).
Are you sure you were tensioning the blade properly?
Chris
On Mon, 03 Apr 2006 17:12:25 GMT, "Toller" <[email protected]> wrote:
>I thought this was a brilliant idea, but it failed completely. Why?
>
>I opened a digital micrometer to 4" and clamped the two ends to a band saw
>blade. I then tensioned the blade. I figured the micrometer jaws would be
>pulled apart a few thousanths and I could determine the tension.
>
>Nothing happened. I flipped the tension lever back and fourth, but it stood
>relentlessly at 4". The ends were clamped securely and the micrometer took
>very little force to move, so I don't think they were just slipping.
>
>Shouldn't this work, or at least do something?
>
I can assure you it will work, at least with a dial indicator and
probe.
and the winner is?
On Wed, 12 Apr 2006 21:19:19 -0400, Tom Watson <[email protected]> wrote:
>On Wed, 12 Apr 2006 10:38:40 -0500, "Swingman" <[email protected]> wrote:
>
>>Recently 'inherited' an Iturra "Blade Gage" which works on the same
>>principle.
>>
>>Made me immediately upgrade the tension spring in my US Delta 14" bandsaw.
>
>I would have thought that an old musician like you would have used the
>"tuning fork method".
>
>You can look it up.
>
>When it first came out it didn't make a lot of sense for guys who
>couldn't hear different notes, but in an age where a tuning checker
>can be had for twenty bucks it might make sense to tune a bandsaw
>blade according to the note it makes when plucked.
>
>
>Regards,
>
>Tom Watson
>
>tjwatson1ATcomcastDOTnet (real email)
>
>http://home.comcast.net/~tjwatson1/
I think I got plucked when I bought my saw.. *g*
Mac
https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm
On Mon, 3 Apr 2006 11:29:16 -0600, Toller wrote
(in article <[email protected]>):
>
> "Chris Friesen" <[email protected]> wrote in message
> news:[email protected]...
>> Toller wrote:
>>
>>> I opened a digital micrometer to 4" and clamped the two ends to a band
>>> saw blade. I then tensioned the blade. I figured the micrometer jaws
>>> would be pulled apart a few thousanths and I could determine the tension.
>>
>>> Shouldn't this work, or at least do something?
>>
>> Yes, and in fact FWW had an article on a tensiometer based on similar
>> technique (except they used feeler gauges).
>>
>> Are you sure you were tensioning the blade properly?
>>
> I hope so. I have the indicator set to 3/4". With the lever in one
> position the blade is floppy; in the other it is taut. That's right isn't
> it? Hey, I just bought the saw last week; I don't discount the possibility
> that I don't know what I am doing.
>
>
For my MM 16" saw I used a dial indicator with mounts about 12" apart. The
calculations are straight forward (I posted the process w/pictures on the
yahoo MM group several years ago). I don't remember exactly, but it was
somewhere about 0.003" to tension a 1" blade and my indicator was graduated
such that a full revolution is 0.004".
You really need a sensitive instrument to tension a blade especially if your
mount points are only 6" apart.
-Bruce
No.
"Toller" <[email protected]> wrote in message
news:[email protected]...
> Shouldn't this work, or at least do something?
>
>
"todd" <[email protected]> wrote in message
news:[email protected]...
> "John Martin" <[email protected]> wrote in message
> news:[email protected]...
>>
>> Toller wrote:
>>> I thought this was a brilliant idea, but it failed completely. Why?
>>>
>>> I opened a digital micrometer to 4" and clamped the two ends to a band
>>> saw
>>> blade. I then tensioned the blade. I figured the micrometer jaws would
>>> be
>>> pulled apart a few thousanths and I could determine the tension.
>>>
>>> Nothing happened. I flipped the tension lever back and fourth, but it
>>> stood
>>> relentlessly at 4". The ends were clamped securely and the micrometer
>>> took
>>> very little force to move, so I don't think they were just slipping.
>>>
>>> Shouldn't this work, or at least do something?
>>
>> If you clamp a micrometer spindle it won't turn. Why would you expect
>> the reading to change?
>>
>> John Martin
>
> I assumed Toller meant to say he was using calipers, rather than a
> micrometer.
>
> todd
That is correct, a caliper rather than a screw micrometer.
"JeffB" <[email protected]> wrote in message
news:%[email protected]...
> The article indicates that over a 5" length (open the calipers to 5") the
> blade should stretch .001" per 6000 psi tension. Therefore a properly
> tensioned blade should read about .003".
> --
My caliper gives repeatable measurements to .001", so it should be accurate
enough to do the job. Maybe it has more resistance than I think.
"Chris Friesen" <[email protected]> wrote in message
news:[email protected]...
> Toller wrote:
>
>> I opened a digital micrometer to 4" and clamped the two ends to a band
>> saw blade. I then tensioned the blade. I figured the micrometer jaws
>> would be pulled apart a few thousanths and I could determine the tension.
>
>> Shouldn't this work, or at least do something?
>
> Yes, and in fact FWW had an article on a tensiometer based on similar
> technique (except they used feeler gauges).
>
> Are you sure you were tensioning the blade properly?
>
I hope so. I have the indicator set to 3/4". With the lever in one
position the blade is floppy; in the other it is taut. That's right isn't
it? Hey, I just bought the saw last week; I don't discount the possibility
that I don't know what I am doing.
"Tom Watson" wrote in message
"Swingman" wrote:
>
> >Recently 'inherited' an Iturra "Blade Gage" which works on the same
> >principle.
> >
> >Made me immediately upgrade the tension spring in my US Delta 14"
bandsaw.
>
> I would have thought that an old musician like you would have used the
> "tuning fork method".
>
> You can look it up.
>
> When it first came out it didn't make a lot of sense for guys who
> couldn't hear different notes, but in an age where a tuning checker
> can be had for twenty bucks it might make sense to tune a bandsaw
> blade according to the note it makes when plucked.
I've "plucked" on it for years, hell even executed a mean harp gliss on the
damn thing a time or two, but the old tension spring was shot to hell, so
even under full compression it was about 1/5th of the needed compression for
the size blade ... basically it would pluck the same old tune, but more than
a few octaves too low.
What a difference with the new tension spring ... now it really sings. ;)
--
www.e-woodshop.net
Last update: 12/13/05
"Toller" <[email protected]> writes:
> I thought this was a brilliant idea, but it failed completely. Why?
>
> I opened a digital micrometer to 4" and clamped the two ends to a band saw
> blade. I then tensioned the blade. I figured the micrometer jaws would be
> pulled apart a few thousanths and I could determine the tension.
So you are measuring stretch?
What if you apply a deflection?
--
Sending unsolicited commercial e-mail to this account incurs a fee of
$500 per message, and acknowledges the legality of this contract.
"Toller" <[email protected]> wrote in message
news:[email protected]...
>I thought this was a brilliant idea, but it failed completely. Why?
>
> I opened a digital micrometer to 4" and clamped the two ends to a band saw
> blade. I then tensioned the blade. I figured the micrometer jaws would
> be pulled apart a few thousanths and I could determine the tension.
>
> Nothing happened. I flipped the tension lever back and fourth, but it
> stood relentlessly at 4". The ends were clamped securely and the
> micrometer took very little force to move, so I don't think they were just
> slipping.
>
> Shouldn't this work, or at least do something?
I'd be very dubious of any results you would get if you could even get this
to work. The amount of error in your measurement is bound to be a large
percentage of the measurement, which means your calculated readings would be
all over the map if you factored in measurement error.
The really cool way to do this would be with a strain gage. Glue it on,
load it up to a predetermined change in resistance, and voila.
todd
On Mon, 03 Apr 2006 17:12:25 GMT, "Toller" <[email protected]> wrote:
>I thought this was a brilliant idea, but it failed completely. Why?
>
>I opened a digital micrometer to 4" and clamped the two ends to a band saw
>blade. I then tensioned the blade. I figured the micrometer jaws would be
>pulled apart a few thousanths and I could determine the tension.
>
>Nothing happened. I flipped the tension lever back and fourth, but it stood
>relentlessly at 4". The ends were clamped securely and the micrometer took
>very little force to move, so I don't think they were just slipping.
>
>Shouldn't this work, or at least do something?
>
yes and no, but not right away...
Sorry.. loan business flashback.. *g*
I find that I just don't CARE how correct my blade tension is... sinful by rec
standards, I admit, but the truth..
I set it to the gauge and "pluck" it like a guitar string... I've never found
out if it's the right pitch, but it comforts me, somehow..
If it cuts straight and sounds ok.. doesn't slide on the tire or bog the motor
down, I figure it's right enough..
I loosen it a couple of turns at night and try to tighten it about the same in
the morning..
I just can't get myself to care enough about a $12 blade to spend a lot of time
getting it ready, and then checking it again the next day..
This sort of leads (ok rambles) to another question... on the machines with
levers, does it leave the tension EXACTLY where it was when you loosen it, wait
over night and retighten?
Mac
https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm
"John Martin" <[email protected]> wrote in message
news:[email protected]...
>
> Toller wrote:
>> I thought this was a brilliant idea, but it failed completely. Why?
>>
>> I opened a digital micrometer to 4" and clamped the two ends to a band
>> saw
>> blade. I then tensioned the blade. I figured the micrometer jaws would
>> be
>> pulled apart a few thousanths and I could determine the tension.
>>
>> Nothing happened. I flipped the tension lever back and fourth, but it
>> stood
>> relentlessly at 4". The ends were clamped securely and the micrometer
>> took
>> very little force to move, so I don't think they were just slipping.
>>
>> Shouldn't this work, or at least do something?
>
> If you clamp a micrometer spindle it won't turn. Why would you expect
> the reading to change?
>
> John Martin
I assumed Toller meant to say he was using calipers, rather than a
micrometer.
todd
Toller wrote:
> "JeffB" <[email protected]> wrote in message
> news:%[email protected]...
>
>>The article indicates that over a 5" length (open the calipers to 5") the
>>blade should stretch .001" per 6000 psi tension. Therefore a properly
>>tensioned blade should read about .003".
>>--
>
> My caliper gives repeatable measurements to .001", so it should be accurate
> enough to do the job. Maybe it has more resistance than I think.
Not to hijack this thread or anything, but I'd like very much to try
this with a dial indicator. You don't have a reference for the stretch
properties of the various metals for bandsaw blades, do you?
I'm using timberwolf silicon steel blades, but I didn't read anything on
this in the Suffolk brochure...
er
--
email not valid
On 4 Apr 2006 02:23:06 GMT, Bruce Barnett
<[email protected]> wrote:
>"Toller" <[email protected]> writes:
>
>> I thought this was a brilliant idea, but it failed completely. Why?
>>
>> I opened a digital micrometer to 4" and clamped the two ends to a band saw
>> blade. I then tensioned the blade. I figured the micrometer jaws would be
>> pulled apart a few thousanths and I could determine the tension.
>
>So you are measuring stretch?
>What if you apply a deflection?
ok.. I guess it's better to ask a dumb question that make a dumb mistake...
Before measuring stretch and deflection, should the blade be at some preset
tightness or something?
Opps.. sorry, tightness wasn't listed, maybe preset tension?
Maybe I'm just not seeing something here, but if I take my cheap chi-wan-ese saw
and loosen the tensioning knob 5 turns would I get the same results from this
test as if I'd tightened it 5 turns instead?
Mac
https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm