disk caliper redux

On Fri, 16 Feb 2007 23:30:28 -0600, A Muzi <[email hidden]>

Quoted message said:

Quoted message said:

Quoted message said:

> <[email hidden]> wrote:
> [snip]

Quoted message said:

Quoted message said:

> jim beam wrote
>> 2. that the stress/strain graph quoted for deformation theory is for a
>> different material to that from spokes are actually made - as shown in
>> different subsequent actual tensile samples graphs?
> [snip]

Quoted message said:

Quoted message said:

[email hidden] wrote:
> For the benefit of puzzled readers . . .
> In Jobst's book "The Bicycle Wheel," there's a stress-strain graph
> showing a yield step or notch, meaning a section in the upward curve
> where things behave oddly:
> ^ x
> | x
> stress- x
> tension x
> x
> x x
> x x x
> x
> strain-elongation -->
> But no such notch appears on the stress-strain graphs of various
> spokes being pulled apart in the back of the book in any edition (the
> first edition includes carbon spokes, as well as modern stainless
> steel spokes).

Quoted message said:

Quoted message said:

Unless jim has zero knowledge of metallurgy (which I doubt) he's doing
his usual: raising red herrings and false representations in a
compulsive attempt to look smarter than Jobst.
Jobst's stress-strain curve on p.32 - the one with the notch - is not
presented as representing any particular alloy. In fact, it's a
standard "first introduction" curve, used to explain the concepts to a
beginner, and it contains that yield notch because the notch is a
feature of mild steel, which is the most common metal used in
manufacturing. For web examples, see http://en.wikipedia.org/wiki/Stress-strain_curve
or http://tinyurl.com/2qhxut
or http://tinyurl.com/35th8a

In almost any engineering book on material properties, that curve is
printed in the first couple chapters, and almost every author chooses
to show the notch just as Jobst has done. But again, the curve is
printed as a general example and introduction to concepts - exactly
what Jobst has done. If it matters, the author might point out that
(most) other metals don't have the notch. My guess is that Jobst
didn't mention it because it has no importance in bicycle wheels.

In the back of _The Bicycle Wheel_ Jobst gives specific curves for
spoke alloys. Those curves are not intended to be general, but
specific to those test results. Those metals don't display the notch,
so of course the notch is not shown. His curves appear to be
accurate.

I'm not surprised that Carl doesn't know this. It's the kind of thing
one learns in metallurgy and/or engineering classes, not English
classes.

But jim beam obviously should know this. As usual, his portrayal of
this as a mistake on Jobst's part is dishonest and cowardly.

Quoted message said:

"Those alloys don't display the notch, so of course the notch is not
shown."

In other words, the stainless steel spokes tested in the appendix
don't match the generalized example for a different material?

If so, the generalized example hardly illustrates what's happening
with the stainless steel spokes, which is what it's supposed to be
doing.

I'm surprised that you're not following what seems to be an obvious
problem in the text, so forgive me for repeating it--a yield-notch
graph is apparently intended to illustrate the behavior of stainless
steel spokes that don't apparently exhibit such behavior.

As for the accuracy of the curves from the actual testing, I assume
that they're reasonably accurate, but probably not terribly detailed.

After all, the carbon-steel spokes tested and graphed in the first
edition show no signs of any yield notch, which would be expected.

-snip-

Huh? Why would you expect a high carbon steel to behave like mild steel?

Dear Andrew,

Er, because (as Jim Beam was too soft-hearted to say) I'm dim-witted
and didn't pay enough attention to what he's said over the years?

I may still be wrong, but I think that Jim just corrected me.

If I understand things now, his point is that stainless steel doesn't
exhibit the yield notch behavior (I had that right) and that neither
do carbon steel spokes (I had that wrong).

Only lower carbon (or maybe unworked carbon) steel shows the yield
notch, not the higher carbon steel used in the spokes tested in the
1981 edition (they vanished in the later editions, since stainless
steel pretty much replaced them).

I mistakenly thought that the lack of a notch in the carbon spoke
stress-strain graphs was due to the testing not being done in fine
enough detail (after all, it was intended to show the ultimate
strength of the spokes, not fine detail).

But I now think that Jim Beam's point is that no yield notch showed up
because there simply was none--the higher carbon steel spokes, as you
point out, behave differently.

In short, none of the spokes tested, carbon or stainless, exhibited
the yield-notch behavior shown in the idealized graph in the text of
"The Bicycle Wheel."

(Stand by for further corrections. What ultimately interests me is
whether the graph with the yield notch is showing us how spokes
behave. It could an outright mistake, just a poorly chosen example, or
somehow correct.)

Cheers,

Carl Fogel

Tim McNamara said:

In article <[email hidden]>,

jim beam said:

Tim McNamara said:

In article <[email hidden]>,
jim beam <[email hidden]> wrote:

> Tim McNamara wrote: <snip [censored]>
>> Apparently the same problems apply to metallurgical education.
> really? so why is it poor old jimmy beam, the uneducated one,
> that has to ask questions about a long time "peer reviewed" bible
> - "the bicycle wheel"? if y'all are so damned educated, smart and
> engineering professorial, how come y'all didn't figure out:
>
> 1. that the tensiometer math doesn't take account of spoke gauge?

Given that Jobst has commented on this in the newsgroup when
discussing the shortcomings in tensiometer design and usage, it
seems that you are not in fact the only one.

after i brought it up. but that's not the point. the point is, the
other so-called "engineers" here haven't bothered to read or think
about this stuff. nor did other self-appointed "experts". either
they read it and decided it wasn't worth the hassle since jobst is
always /so/ hostile to comment. or it was missed. did /you/ spot
it? [rhetorical]

Don't break your arm patting yourself on the back, jim.

Don't give him too much credit. The page you linked to shows that Jobst was
discussing this before "jim beam" graced our presence.

Tim McNamara said:

In article <[email hidden]>,

jim beam said:

Tim McNamara said:

In article <[email hidden]>,
jim beam <[email hidden]> wrote:

> Tim McNamara wrote: <snip [censored]>
>> Apparently the same problems apply to metallurgical education.
> really? so why is it poor old jimmy beam, the uneducated one,
> that has to ask questions about a long time "peer reviewed" bible
> - "the bicycle wheel"? if y'all are so damned educated, smart and
> engineering professorial, how come y'all didn't figure out:
>
> 1. that the tensiometer math doesn't take account of spoke gauge?

Given that Jobst has commented on this in the newsgroup when
discussing the shortcomings in tensiometer design and usage, it
seems that you are not in fact the only one.

after i brought it up. but that's not the point. the point is, the
other so-called "engineers" here haven't bothered to read or think
about this stuff. nor did other self-appointed "experts". either
they read it and decided it wasn't worth the hassle since jobst is
always /so/ hostile to comment. or it was missed. did /you/ spot
it? [rhetorical]

Don't break your arm patting yourself on the back, jim. As for whether
I would have spotted it, the answer is actually "yes." See, back when I
was in school, I was taught to zero out measurement tools whenever
possible. I zero out my tensiometer before use to reduce the
measurement error as much as possible. Been doing it for years before
you started posting here, because it was so bloody obvious.

[snip]

Dear Tim,

Again, you've misunderstood the point.

Even after you zero the measuring device, the thickness of the spoke
affects the tension reading.

In a small span, the greater bending resistance of the thicker spoke
means that the same deflection requires more force against greater
tension than with a thinner spoke.

The same thing is true when the spoke is made of different materials.

That's why the DT Swiss tables show different tensions for the same
deflection for spokes of different thickness and material. See the
chart at the bottom of this pdf:

http://www.dtswiss.com/data/files/MAN_EN_51202133804.pdf

As you can see, when the zeroed DT Swiss micrometer is used, a spoke
witht 1000 newtons of tension will deflect 1.77, 2.19, or 3.00 mm,
depending on whether it is a 1.8, 2.0, or 2.34 mm thick straight steel
spoke.

If it is a 2.0 mm straight titanium spoke, it will deflect 2.10 mm
instead of the 2.19 mm of the 2.0 mm straight steel spoke at the same
tension.

Cheers,

Carl Fogel

Quoted message said:

Tim McNamara said:

In article <[email hidden]>,

jim beam said:

Tim McNamara wrote:
> In article <[email hidden]>,
> jim beam <[email hidden]> wrote:
>
>> Tim McNamara wrote: <snip [censored]>
>>> Apparently the same problems apply to metallurgical education.
>> really? so why is it poor old jimmy beam, the uneducated one,
>> that has to ask questions about a long time "peer reviewed" bible
>> - "the bicycle wheel"? if y'all are so damned educated, smart and
>> engineering professorial, how come y'all didn't figure out:
>>
>> 1. that the tensiometer math doesn't take account of spoke gauge?
>
> Given that Jobst has commented on this in the newsgroup when
> discussing the shortcomings in tensiometer design and usage, it
> seems that you are not in fact the only one.

after i brought it up. but that's not the point. the point is, the
other so-called "engineers" here haven't bothered to read or think
about this stuff. nor did other self-appointed "experts". either
they read it and decided it wasn't worth the hassle since jobst is
always /so/ hostile to comment. or it was missed. did /you/ spot
it? [rhetorical]

Don't break your arm patting yourself on the back, jim. As for whether
I would have spotted it, the answer is actually "yes." See, back when I
was in school, I was taught to zero out measurement tools whenever
possible. I zero out my tensiometer before use to reduce the
measurement error as much as possible. Been doing it for years before
you started posting here, because it was so bloody obvious.

[snip]

Dear Tim,

Again, you've misunderstood the point.

Even after you zero the measuring device, the thickness of the spoke
affects the tension reading.

In a small span, the greater bending resistance of the thicker spoke
means that the same deflection requires more force against greater
tension than with a thinner spoke.

The same thing is true when the spoke is made of different materials.

That's why the DT Swiss tables show different tensions for the same
deflection for spokes of different thickness and material. See the
chart at the bottom of this pdf:

http://www.dtswiss.com/data/files/MAN_EN_51202133804.pdf

As you can see, when the zeroed DT Swiss micrometer is used, a spoke
witht 1000 newtons of tension will deflect 1.77, 2.19, or 3.00 mm,
depending on whether it is a 1.8, 2.0, or 2.34 mm thick straight steel
spoke.

If it is a 2.0 mm straight titanium spoke, it will deflect 2.10 mm
instead of the 2.19 mm of the 2.0 mm straight steel spoke at the same
tension.

Cheers,

Carl Fogel

It belatedly occurs to me that many readers may not be familiar with
various spoke tension gauges, so it's necessary to explain that the DT
Swiss method of measuring reverses the expected pattern:

"The higher the spoke tension, the smaller the deflection of the
spoke. The deflection of the spoke is measured indirectly and
reflected on the dial gauge (3). The smaller the deflection, the
higher the measuring value. In other words, the higher spoke tension
the greater the measured value."

http://www.dtswiss.com/data/files/MAN_EN_51202133804.pdf

That's why the "deflection" measurements appear to go the wrong way in
the table and the examples that I gave. Instead of measuring how far
the spoke moves from its original unbent position, the tool measures
how near the bending spoke comes to reference point far beyond the
bend:

| \
| \A____3.0mm for stiffer 2.34 spoke________Z
| /
| /

| \
| \A____2.19mm for less stiff 2.00 spoke___Z
| /
| /

The distance from bend-point A to fixed-point Z in the tool is greater
for the thicker spoke at the same tension.

CF

On Fri, 16 Feb 2007 21:09:26 -0700, carlfogel wrote:

<snip>

Quoted message said:

Dear Frank,

"Those alloys don't display the notch, so of course the notch is not
shown."

In other words, the stainless steel spokes tested in the appendix
don't match the generalized example for a different material?

If so, the generalized example hardly illustrates what's happening
with the stainless steel spokes, which is what it's supposed to be
doing.

I'm surprised that you're not following what seems to be an obvious
problem in the text, so forgive me for repeating it--a yield-notch
graph is apparently intended to illustrate the behavior of stainless
steel spokes that don't apparently exhibit such behavior.

As for the accuracy of the curves from the actual testing, I assume
that they're reasonably accurate, but probably not terribly detailed.

After all, the carbon-steel spokes tested and graphed in the first
edition show no signs of any yield notch, which would be expected.

The tests, as far as I know, were intended primarily to show how
strong various spokes were--that is, the 2 mm straight spokes all fail
at about the load, regardless of how far they stretch before doing so,

Cheers,

Carl Fogel

Carl,
I agree that the chart, while not technically incorrect, can be confusing to
a newcomer to the topic. However, it's not clear to me what about this makes
you think that it's worthwhile to ask the opinion of another expert.

"jim beam" sometimes suggests that Jobst improperly relies on the idea that
steel has no endurance limit (if that's the term), but I don't see it. He
characterizes fatigue limit and fatigue life in terms of the number of
cycles the material is subjected to.

For instance, on page 30:

"The fatigue limit is how often the metal can be stretched or bent back and
forth in the elastic stress zone before it develops a crack and breaks. For
most applications fatigue life is measured in millions of cycles."

And in the caption to Figure 15:

"The fatigue life curve shown is for an ideal metal under stress. A material
whose stress changes lie within this curve can withstand a nearly infinite
number (millions) of stress cycles." Is that inaccurate? I thought there was
a consensus in the thread about Sapim's fatigue testing that spokes
subjected to normal stresses do last millions of cycles.

In article
<[email hidden]>,

Quoted message said:

Tim McNamara said:

In article <[email hidden]>,

jim beam said:

since the previous thread is now too deep for me to follow on a
threaded newsreader, here's a summary of the debate so far:

Indeed, it was. "Snipping" extraneous material is the standard way to
manage this, but you and a couple of others don't do it.

[snip]

Dear Tim,

You've misunderstood the problem, which has nothing to do with
snipping.

When there are so many replies to replies, the thread tree becomes
unwieldy. Many threaded newsreaders have a limit to how they display
the tree and stop indenting at some point.

For example, my older version of Forte Free Agent just stops indenting
after some limit--I think that it's 32 replies-to-replies.

Instead of this, where C is the 32nd reply to a reply

A
B
C
L
M
N
X
Y
Z

It shows this:

A
B
C
L
M
N
X
Y
Z

You can no longer tell at a glance that Y and Z reply to X.

If you look at the original thread in Google Groups, you can see
another way of handling an excessively deep thread tree:

http://groups.google.com/group/rec.bicycles.tech/browse_frm/thread/879729f063acfce8/9b0543f5ab444ce6#9b0543f5ab444ce6

Page down to posts 272/273, and you'll see a section where there are
lots of huge indentations. My post 273 is a reply to post 272 above
it, from dabac, but the indentation doesn't show this.

Instead, dabac's post has been indented as far to the right as
Google's display allows, so my reply to his post is shoved all the way
back to the left side of the tree (with no explanation).

Google turns what should be this:

A
B
C
D
E

into this:

A
B
C
D
E

You can no longer tell that E replies to D.

Again, it has nothing to do with snipping, just with how to indent to
show which post the next post replies to. Snipping doesn't affect the
thread-tree/message-list display.

I think that Jim Beam's suggestion to start a new thread is one good
solution to problem of a thread that's gotten so deeply indented on a
tree display that following it becomes difficult.

Broken news reader is not a sufficient reason to break
off a thread and start a new one. News readers are out
there that can handle unbounded trees without there
brain exploding. A program module for this purpose is
an undergraduate homework assignment.

--
Michael Press

Michael Press said:

In article
<[email hidden]>,

Don't forget to top post!

Quoted message said:

Quoted message said:

On Fri, 16 Feb 2007 10:19:12 -0600, Tim McNamara
<[email hidden]> wrote:

Quoted message said:

Quoted message said:

In article <[email hidden]>,
jim beam <[email hidden]> wrote:

Quoted message said:

Quoted message said:

> since the previous thread is now too deep for me to follow on a
> threaded newsreader, here's a summary of the debate so far:

Quoted message said:

Quoted message said:

Indeed, it was. "Snipping" extraneous material is the standard way to
manage this, but you and a couple of others don't do it.

Quoted message said:

[snip]

Quoted message said:

Dear Tim,

Quoted message said:

You've misunderstood the problem, which has nothing to do with
snipping.

Quoted message said:

When there are so many replies to replies, the thread tree becomes
unwieldy. Many threaded newsreaders have a limit to how they display
the tree and stop indenting at some point.

Quoted message said:

For example, my older version of Forte Free Agent just stops indenting
after some limit--I think that it's 32 replies-to-replies.

Quoted message said:

Instead of this, where C is the 32nd reply to a reply

Quoted message said:

A
B
C
L
M
N
X
Y
Z

Quoted message said:

It shows this:

Quoted message said:

A
B
C
L
M
N
X
Y
Z

Quoted message said:

You can no longer tell at a glance that Y and Z reply to X.

Quoted message said:

If you look at the original thread in Google Groups, you can see
another way of handling an excessively deep thread tree:

Quoted message said:

http://groups.google.com/group/rec.bicycles.tech/browse_frm/thread/87...

Quoted message said:

Page down to posts 272/273, and you'll see a section where there are
lots of huge indentations. My post 273 is a reply to post 272 above
it, from dabac, but the indentation doesn't show this.

Quoted message said:

Instead, dabac's post has been indented as far to the right as
Google's display allows, so my reply to his post is shoved all the way
back to the left side of the tree (with no explanation).

Quoted message said:

Google turns what should be this:

Quoted message said:

A
B
C
D
E

Quoted message said:

into this:

Quoted message said:

A
B
C
D
E

Quoted message said:

You can no longer tell that E replies to D.

Quoted message said:

Again, it has nothing to do with snipping, just with how to indent to
show which post the next post replies to. Snipping doesn't affect the
thread-tree/message-list display.

Quoted message said:

I think that Jim Beam's suggestion to start a new thread is one good
solution to problem of a thread that's gotten so deeply indented on a
tree display that following it becomes difficult.

Broken news reader is not a sufficient reason to break
off a thread and start a new one. News readers are out
there that can handle unbounded trees without there
brain exploding. A program module for this purpose is
an undergraduate homework assignment.

--
Michael Press- Hide quoted text -

- Show quoted text -

On Sat, 17 Feb 2007 11:44:32 -0700, carlfogel wrote:

<snip>

Quoted message said:

Dear Tim,

Again, you've misunderstood the point.

Even after you zero the measuring device, the thickness of the spoke
affects the tension reading.

In a small span, the greater bending resistance of the thicker spoke
means that the same deflection requires more force against greater
tension than with a thinner spoke.

The same thing is true when the spoke is made of different materials.

That's why the DT Swiss tables show different tensions for the same
deflection for spokes of different thickness and material. See the
chart at the bottom of this pdf:

http://www.dtswiss.com/data/files/MAN_EN_51202133804.pdf

As you can see, when the zeroed DT Swiss micrometer is used, a spoke
witht 1000 newtons of tension will deflect 1.77, 2.19, or 3.00 mm,
depending on whether it is a 1.8, 2.0, or 2.34 mm thick straight steel
spoke.

If it is a 2.0 mm straight titanium spoke, it will deflect 2.10 mm
instead of the 2.19 mm of the 2.0 mm straight steel spoke at the same
tension.

That may be true for the DT-Swiss tensiometer, but Jobst's tensiometer is of
a different design. It's not clear to me why you or "jim beam" think that
Jobst's equations should accommodate the results taken from a tensiometer
that he considers to be an inferior design.

See the first post on this page:

http://yarchive.net/bike/tensiometer.html

Jobst says:

"For this reason I designed a precision gauge that measures from the
support side and uses a dial micrometer so that small deflections can
be used. It also zeroes on the spoke and, because it uses such a
small deflection, bending stiffness over a 100mm span is small enough
to make the difference between 1.6 and 2.0mm diameter spokes
insignificant."

It seems to me that the implication of that is that the spoke diameter can
be left out of his equations because they are insignificant when the
measurements are taken with his instrument. Do you have some reason to
disagree with that?

In article <[email hidden]>,

Gary Young said:

Tim McNamara said:

In article <[email hidden]>,

jim beam said:

Tim McNamara wrote:
> In article <[email hidden]>,
> jim beam <[email hidden]> wrote:
>
>> Tim McNamara wrote: <snip [censored]>
>>> Apparently the same problems apply to metallurgical education.
>> really? so why is it poor old jimmy beam, the uneducated one,
>> that has to ask questions about a long time "peer reviewed"
>> bible - "the bicycle wheel"? if y'all are so damned educated,
>> smart and engineering professorial, how come y'all didn't
>> figure out:
>>
>> 1. that the tensiometer math doesn't take account of spoke
>> gauge?
>
> Given that Jobst has commented on this in the newsgroup when
> discussing the shortcomings in tensiometer design and usage, it
> seems that you are not in fact the only one.

after i brought it up. but that's not the point. the point is,
the other so-called "engineers" here haven't bothered to read or
think about this stuff. nor did other self-appointed "experts".
either they read it and decided it wasn't worth the hassle since
jobst is always /so/ hostile to comment. or it was missed. did
/you/ spot it? [rhetorical]

Don't break your arm patting yourself on the back, jim.

Don't give him too much credit. The page you linked to shows that
Jobst was discussing this before "jim beam" graced our presence.

Yup.

In article <[email hidden]>,

Quoted message said:

Tim McNamara said:

In article <[email hidden]>,

jim beam said:

Tim McNamara wrote:
> In article <[email hidden]>,
> jim beam <[email hidden]> wrote:
>
>> Tim McNamara wrote: <snip [censored]>
>>> Apparently the same problems apply to metallurgical education.
>> really? so why is it poor old jimmy beam, the uneducated one,
>> that has to ask questions about a long time "peer reviewed"
>> bible - "the bicycle wheel"? if y'all are so damned educated,
>> smart and engineering professorial, how come y'all didn't
>> figure out:
>>
>> 1. that the tensiometer math doesn't take account of spoke
>> gauge?
>
> Given that Jobst has commented on this in the newsgroup when
> discussing the shortcomings in tensiometer design and usage, it
> seems that you are not in fact the only one.

after i brought it up. but that's not the point. the point is,
the other so-called "engineers" here haven't bothered to read or
think about this stuff. nor did other self-appointed "experts".
either they read it and decided it wasn't worth the hassle since
jobst is always /so/ hostile to comment. or it was missed. did
/you/ spot it? [rhetorical]

Don't break your arm patting yourself on the back, jim. As for
whether I would have spotted it, the answer is actually "yes." See,
back when I was in school, I was taught to zero out measurement
tools whenever possible. I zero out my tensiometer before use to
reduce the measurement error as much as possible. Been doing it for
years before you started posting here, because it was so bloody
obvious.

[snip]

Dear Tim,

Again, you've misunderstood the point.

Carl, I did understand the point. But thank you for your concern.

Quoted message said:

Even after you zero the measuring device, the thickness of the spoke
affects the tension reading.

The bending stiffness of the spoke under no tension affects the reading
as does the diameter of the spoke. And the force used by the
tensiometer also affects the tension reading, since by bending the spoke
into a curve the measurement raises the spoke tension. Friction and
binding can also play a part depending on the design.

Quoted message said:

In a small span, the greater bending resistance of the thicker spoke
means that the same deflection requires more force against greater
tension than with a thinner spoke.

The same thing is true when the spoke is made of different materials.

That's why the DT Swiss tables show different tensions for the same
deflection for spokes of different thickness and material.

<snip> Umm, Carl? Duh.

Let's go back to what I wrote: "I zero out my tensiometer before use to
reduce the measurement error as much as possible." Let's emphasize that
"as much as possible" part. As a person professionally devoted to the
use of the English language, I am sure you understand the meaning "as
much as possible." I have long understood that zeroing out my
tensiometer only reduces the error of measurement, it does not eliminate
it.

Tim McNamara said:

In article <[email hidden]>,

Quoted message said:

Tim McNamara said:

In article <[email hidden]>,
jim beam <[email hidden]> wrote:

> Tim McNamara wrote:
> > In article <[email hidden]>,
> > jim beam <[email hidden]> wrote:
> >
> >> Tim McNamara wrote: <snip [censored]>
> >>> Apparently the same problems apply to metallurgical education.
> >> really? so why is it poor old jimmy beam, the uneducated one,
> >> that has to ask questions about a long time "peer reviewed"
> >> bible - "the bicycle wheel"? if y'all are so damned educated,
> >> smart and engineering professorial, how come y'all didn't
> >> figure out:
> >>
> >> 1. that the tensiometer math doesn't take account of spoke
> >> gauge?
> >
> > Given that Jobst has commented on this in the newsgroup when
> > discussing the shortcomings in tensiometer design and usage, it
> > seems that you are not in fact the only one.
>
> after i brought it up. but that's not the point. the point is,
> the other so-called "engineers" here haven't bothered to read or
> think about this stuff. nor did other self-appointed "experts".
> either they read it and decided it wasn't worth the hassle since
> jobst is always /so/ hostile to comment. or it was missed. did
> /you/ spot it? [rhetorical]

Don't break your arm patting yourself on the back, jim. As for
whether I would have spotted it, the answer is actually "yes." See,
back when I was in school, I was taught to zero out measurement
tools whenever possible. I zero out my tensiometer before use to
reduce the measurement error as much as possible. Been doing it for
years before you started posting here, because it was so bloody
obvious.

[snip]

Dear Tim,

Again, you've misunderstood the point.

Carl, I did understand the point. But thank you for your concern.

Quoted message said:

Even after you zero the measuring device, the thickness of the spoke
affects the tension reading.

The bending stiffness of the spoke under no tension affects the reading
as does the diameter of the spoke. And the force used by the
tensiometer also affects the tension reading, since by bending the spoke
into a curve the measurement raises the spoke tension. Friction and
binding can also play a part depending on the design.

Quoted message said:

In a small span, the greater bending resistance of the thicker spoke
means that the same deflection requires more force against greater
tension than with a thinner spoke.

The same thing is true when the spoke is made of different materials.

That's why the DT Swiss tables show different tensions for the same
deflection for spokes of different thickness and material.

<snip> Umm, Carl? Duh.

Let's go back to what I wrote: "I zero out my tensiometer before use to
reduce the measurement error as much as possible." Let's emphasize that
"as much as possible" part. As a person professionally devoted to the
use of the English language, I am sure you understand the meaning "as
much as possible." I have long understood that zeroing out my
tensiometer only reduces the error of measurement, it does not eliminate
it.

Dear Tim,

I think that you missed the point again because you were too busy
explaining how you didn't.

Jim Beam's point, easily confirmed by reference to tables for any
major micrometer-style spoke tension gauge, is that a 2mm spoke will
deflect a different distance than a 1.8 mm spoke under the same
deflection force because the different bending stiffness of the two
spokes.

The same is true of spokes with the same dimensions made of similar
materials because the different materials have different bending
strengths.

Consider a straight-gauge 2.0 mm spoke.

If it's made of stainless steel, the second column of the DT Swiss
table shows that a deflection of 1.76 mm means a spoke tension of 600
newtons.

If it's made of titanium, the last column of the DT Swiss table shows
that a deflection of 1.75 mm means a spoke tension of 700 newtons.

Read across the table at the bottom at any level, and you'll see that
the same spoke tension produces different deflection, according to the
spoke material and cross-section.

http://www.dtswiss.com/data/files/MAN_EN_51202133804.pdf

Before explaining again how right you are, see if you can summarize
the point that I'm saying you've missed.

Cheers,

Carl Fogel

In article <[email hidden]>,

Quoted message said:

Quoted message said:

Note that the final factor in the expression, F/h, doesn't actually
depend on F. That is, reducing the applied F also reduces h
proportionally (for given setup). The rest of the terms depend only
on spoke parameters. The point being, reducing the applied force
(which Jobst's device does) doesn't reduce the effect of a change in
spoke diameter.

Quoted message said:

How does this end up under the disk brake heading? Anyway, you may be
right. I visualized the shape of the bend at the inflection points
changing with force (displacement). Are you sure the radius of
curvature remains the same and is small in comparison to the test
span?

The shape of the bend scales linearly with test force, down to a
flat line for a force of zero. Any radii go inversely with this.

Quoted message said:

I may have been relying on false impressions in that respect.
In any event, the calibration curves for 1.8 and 2.0mm diameter spokes
with this instrument are close enough to ignore the difference.

Around the tensions of interest (~100kgF), it's about a 12kgF
difference between 2.0mm and 1.8mm spokes with the same measured
displacement. The difference between 1.8mm and 1.6mm spokes is about
another 10kgF.

-Luns

Luns Tee said:

Quoted message said:

Quoted message said:

Note that the final factor in the expression, F/h, doesn't
actually depend on F. That is, reducing the applied F also
reduces h proportionally (for given setup). The rest of the terms
depend only on spoke parameters. The point being, reducing the
applied force (which Jobst's device does) doesn't reduce the
effect of a change in spoke diameter.

Quoted message said:

Quoted message said:

How does this end up under the disk brake heading? Anyway, you may
be right. I visualized the shape of the bend at the inflection
points changing with force (displacement). Are you sure the radius
of curvature remains the same and is small in comparison to the
test span?

Quoted message said:

The shape of the bend scales linearly with test force, down to a
flat line for a force of zero. Any radii go inversely with this.

Quoted message said:

Quoted message said:

I may have been relying on false impressions in that respect. In
any event, the calibration curves for 1.8 and 2.0mm diameter spokes
with this instrument are close enough to ignore the difference.

Quoted message said:

Around the tensions of interest (~100kgF), it's about a 12kgF
difference between 2.0mm and 1.8mm spokes with the same measured
displacement. The difference between 1.8mm and 1.6mm spokes is
about another 10kgF.

Not to overlook the effect of added spoke tension from a large test
force, such as the one by Hozan that sees tension in slack spokes of a
20" wheel.

Jobst Brandt

In article <[email hidden]>,

Quoted message said:

Tim McNamara said:

In article <[email hidden]>,

Quoted message said:

On Sat, 17 Feb 2007 09:38:24 -0600, Tim McNamara
<[email hidden]> wrote:

>In article <[email hidden]>,
> jim beam <[email hidden]> wrote:
>
>> Tim McNamara wrote:
>> > In article <[email hidden]>,
>> > jim beam <[email hidden]> wrote:
>> >
>> >> Tim McNamara wrote: <snip [censored]>
>> >>> Apparently the same problems apply to metallurgical
>> >>> education.
>> >> really? so why is it poor old jimmy beam, the uneducated
>> >> one, that has to ask questions about a long time "peer
>> >> reviewed" bible - "the bicycle wheel"? if y'all are so
>> >> damned educated, smart and engineering professorial, how
>> >> come y'all didn't figure out:
>> >>
>> >> 1. that the tensiometer math doesn't take account of spoke
>> >> gauge?
>> >
>> > Given that Jobst has commented on this in the newsgroup when
>> > discussing the shortcomings in tensiometer design and usage,
>> > it seems that you are not in fact the only one.
>>
>> after i brought it up. but that's not the point. the point
>> is, the other so-called "engineers" here haven't bothered to
>> read or think about this stuff. nor did other self-appointed
>> "experts". either they read it and decided it wasn't worth the
>> hassle since jobst is always /so/ hostile to comment. or it
>> was missed. did /you/ spot it? [rhetorical]
>
>Don't break your arm patting yourself on the back, jim. As for
>whether I would have spotted it, the answer is actually "yes."
>See, back when I was in school, I was taught to zero out
>measurement tools whenever possible. I zero out my tensiometer
>before use to reduce the measurement error as much as possible.
>Been doing it for years before you started posting here, because
>it was so bloody obvious.

[snip]

Dear Tim,

Again, you've misunderstood the point.

Carl, I did understand the point. But thank you for your concern.

Quoted message said:

Even after you zero the measuring device, the thickness of the
spoke affects the tension reading.

The bending stiffness of the spoke under no tension affects the
reading as does the diameter of the spoke. And the force used by
the tensiometer also affects the tension reading, since by bending
the spoke into a curve the measurement raises the spoke tension.
Friction and binding can also play a part depending on the design.

Quoted message said:

In a small span, the greater bending resistance of the thicker
spoke means that the same deflection requires more force against
greater tension than with a thinner spoke.

The same thing is true when the spoke is made of different
materials.

That's why the DT Swiss tables show different tensions for the
same deflection for spokes of different thickness and material.

<snip> Umm, Carl? Duh.

Let's go back to what I wrote: "I zero out my tensiometer before
use to reduce the measurement error as much as possible." Let's
emphasize that "as much as possible" part. As a person
professionally devoted to the use of the English language, I am sure
you understand the meaning "as much as possible." I have long
understood that zeroing out my tensiometer only reduces the error of
measurement, it does not eliminate it.

Dear Tim,

I think that you missed the point again because you were too busy
explaining how you didn't.

OK, Carl, have it your way.

Quoted message said:

Jim Beam's point, easily confirmed by reference to tables for any
major micrometer-style spoke tension gauge, is that a 2mm spoke will
deflect a different distance than a 1.8 mm spoke under the same
deflection force because the different bending stiffness of the two
spokes.

Yes.

Quoted message said:

The same is true of spokes with the same dimensions made of similar
materials because the different materials have different bending
strengths.

Yes.

Quoted message said:

Consider a straight-gauge 2.0 mm spoke.

OK.

Quoted message said:

If it's made of stainless steel, the second column of the DT Swiss
table shows that a deflection of 1.76 mm means a spoke tension of 600
newtons.

OK.

Quoted message said:

If it's made of titanium, the last column of the DT Swiss table shows
that a deflection of 1.75 mm means a spoke tension of 700 newtons.

OK.

Quoted message said:

Read across the table at the bottom at any level, and you'll see that
the same spoke tension produces different deflection, according to
the spoke material and cross-section.

http://www.dtswiss.com/data/files/MAN_EN_51202133804.pdf

Is there something in this that you think is mysterious?

Quoted message said:

Before explaining again how right you are, see if you can summarize
the point that I'm saying you've missed.

No, thanks, Carl. I'm not really interested in passing an English test
at this stage of my life, nor do I need your passing grade for my life
to be complete. Feel free to believe that I understand, or to
disbelieve.

(Luns Tee) said:

In article <[email hidden]>,

Quoted message said:

Quoted message said:

Note that the final factor in the expression, F/h, doesn't actually
depend on F. That is, reducing the applied F also reduces h
proportionally (for given setup). The rest of the terms depend only
on spoke parameters. The point being, reducing the applied force
(which Jobst's device does) doesn't reduce the effect of a change in
spoke diameter.

Quoted message said:

How does this end up under the disk brake heading? Anyway, you may be
right. I visualized the shape of the bend at the inflection points
changing with force (displacement). Are you sure the radius of
curvature remains the same and is small in comparison to the test
span?

The shape of the bend scales linearly with test force, down to a
flat line for a force of zero. Any radii go inversely with this.

Quoted message said:

I may have been relying on false impressions in that respect.
In any event, the calibration curves for 1.8 and 2.0mm diameter spokes
with this instrument are close enough to ignore the difference.

Around the tensions of interest (~100kgF), it's about a 12kgF
difference between 2.0mm and 1.8mm spokes with the same measured
displacement. The difference between 1.8mm and 1.6mm spokes is about
another 10kgF.

Note that reducing the applied force, which Jobst's device can do
because of the higher precision measurement he makes, does improve the
situation because it reduces the actual change in spoke tension due to
the applied load. That is seen in the equation I posted elsewhere in
this thread, though it didn't include F (the force) but the measured
spoke deflection (which is approximately proportional to the force).

--
Joe Riel

Tim McNamara said:

In article <[email hidden]>,

Quoted message said:

Tim McNamara said:

In article <[email hidden]>,
[email hidden] wrote:

> On Sat, 17 Feb 2007 09:38:24 -0600, Tim McNamara
> <[email hidden]> wrote:
>
> >In article <[email hidden]>,
> > jim beam <[email hidden]> wrote:
> >
> >> Tim McNamara wrote:
> >> > In article <[email hidden]>,
> >> > jim beam <[email hidden]> wrote:
> >> >
> >> >> Tim McNamara wrote: <snip [censored]>
> >> >>> Apparently the same problems apply to metallurgical
> >> >>> education.
> >> >> really? so why is it poor old jimmy beam, the uneducated
> >> >> one, that has to ask questions about a long time "peer
> >> >> reviewed" bible - "the bicycle wheel"? if y'all are so
> >> >> damned educated, smart and engineering professorial, how
> >> >> come y'all didn't figure out:
> >> >>
> >> >> 1. that the tensiometer math doesn't take account of spoke
> >> >> gauge?
> >> >
> >> > Given that Jobst has commented on this in the newsgroup when
> >> > discussing the shortcomings in tensiometer design and usage,
> >> > it seems that you are not in fact the only one.
> >>
> >> after i brought it up. but that's not the point. the point
> >> is, the other so-called "engineers" here haven't bothered to
> >> read or think about this stuff. nor did other self-appointed
> >> "experts". either they read it and decided it wasn't worth the
> >> hassle since jobst is always /so/ hostile to comment. or it
> >> was missed. did /you/ spot it? [rhetorical]
> >
> >Don't break your arm patting yourself on the back, jim. As for
> >whether I would have spotted it, the answer is actually "yes."
> >See, back when I was in school, I was taught to zero out
> >measurement tools whenever possible. I zero out my tensiometer
> >before use to reduce the measurement error as much as possible.
> >Been doing it for years before you started posting here, because
> >it was so bloody obvious.
>
> [snip]
>
> Dear Tim,
>
> Again, you've misunderstood the point.

Carl, I did understand the point. But thank you for your concern.

> Even after you zero the measuring device, the thickness of the
> spoke affects the tension reading.

The bending stiffness of the spoke under no tension affects the
reading as does the diameter of the spoke. And the force used by
the tensiometer also affects the tension reading, since by bending
the spoke into a curve the measurement raises the spoke tension.
Friction and binding can also play a part depending on the design.

> In a small span, the greater bending resistance of the thicker
> spoke means that the same deflection requires more force against
> greater tension than with a thinner spoke.
>
> The same thing is true when the spoke is made of different
> materials.
>
> That's why the DT Swiss tables show different tensions for the
> same deflection for spokes of different thickness and material.

<snip> Umm, Carl? Duh.

Let's go back to what I wrote: "I zero out my tensiometer before
use to reduce the measurement error as much as possible." Let's
emphasize that "as much as possible" part. As a person
professionally devoted to the use of the English language, I am sure
you understand the meaning "as much as possible." I have long
understood that zeroing out my tensiometer only reduces the error of
measurement, it does not eliminate it.

Dear Tim,

I think that you missed the point again because you were too busy
explaining how you didn't.

OK, Carl, have it your way.

Quoted message said:

Jim Beam's point, easily confirmed by reference to tables for any
major micrometer-style spoke tension gauge, is that a 2mm spoke will
deflect a different distance than a 1.8 mm spoke under the same
deflection force because the different bending stiffness of the two
spokes.

Yes.

Quoted message said:

The same is true of spokes with the same dimensions made of similar
materials because the different materials have different bending
strengths.

Yes.

Quoted message said:

Consider a straight-gauge 2.0 mm spoke.

OK.

Quoted message said:

If it's made of stainless steel, the second column of the DT Swiss
table shows that a deflection of 1.76 mm means a spoke tension of 600
newtons.

OK.

Quoted message said:

If it's made of titanium, the last column of the DT Swiss table shows
that a deflection of 1.75 mm means a spoke tension of 700 newtons.

OK.

Quoted message said:

Read across the table at the bottom at any level, and you'll see that
the same spoke tension produces different deflection, according to
the spoke material and cross-section.

http://www.dtswiss.com/data/files/MAN_EN_51202133804.pdf

Is there something in this that you think is mysterious?

Quoted message said:

Before explaining again how right you are, see if you can summarize
the point that I'm saying you've missed.

No, thanks, Carl. I'm not really interested in passing an English test
at this stage of my life, nor do I need your passing grade for my life
to be complete. Feel free to believe that I understand, or to
disbelieve.

Dear Tim,

I think that you may understand now.

You didn't seem to understand before.

Cheers,

Carl Fogel

In article <[email hidden]>,

Quoted message said:

Tim McNamara said:

In article <[email hidden]>,

Quoted message said:

On Sat, 17 Feb 2007 17:09:03 -0600, Tim McNamara
<[email hidden]> wrote:

>In article <[email hidden]>,
> [email hidden] wrote:
>
>> On Sat, 17 Feb 2007 09:38:24 -0600, Tim McNamara
>> <[email hidden]> wrote:
>>
>> >In article <[email hidden]>,
>> > jim beam <[email hidden]> wrote:
>> >
>> >> Tim McNamara wrote:
>> >> > In article <[email hidden]>,
>> >> > jim beam <[email hidden]> wrote:
>> >> >
>> >> >> Tim McNamara wrote: <snip [censored]>
>> >> >>> Apparently the same problems apply to metallurgical
>> >> >>> education.
>> >> >> really? so why is it poor old jimmy beam, the uneducated
>> >> >> one, that has to ask questions about a long time "peer
>> >> >> reviewed" bible - "the bicycle wheel"? if y'all are so
>> >> >> damned educated, smart and engineering professorial, how
>> >> >> come y'all didn't figure out:
>> >> >>
>> >> >> 1. that the tensiometer math doesn't take account of spoke
>> >> >> gauge?
>> >> >
>> >> > Given that Jobst has commented on this in the newsgroup when
>> >> > discussing the shortcomings in tensiometer design and usage,
>> >> > it seems that you are not in fact the only one.
>> >>
>> >> after i brought it up. but that's not the point. the point
>> >> is, the other so-called "engineers" here haven't bothered to
>> >> read or think about this stuff. nor did other self-appointed
>> >> "experts". either they read it and decided it wasn't worth the
>> >> hassle since jobst is always /so/ hostile to comment. or it
>> >> was missed. did /you/ spot it? [rhetorical]
>> >
>> >Don't break your arm patting yourself on the back, jim. As for
>> >whether I would have spotted it, the answer is actually "yes."
>> >See, back when I was in school, I was taught to zero out
>> >measurement tools whenever possible. I zero out my tensiometer
>> >before use to reduce the measurement error as much as possible.
>> >Been doing it for years before you started posting here, because
>> >it was so bloody obvious.
>>
>> [snip]
>>
>> Dear Tim,
>>
>> Again, you've misunderstood the point.
>
>Carl, I did understand the point. But thank you for your concern.
>
>> Even after you zero the measuring device, the thickness of the
>> spoke affects the tension reading.
>
>The bending stiffness of the spoke under no tension affects the
>reading as does the diameter of the spoke. And the force used by
>the tensiometer also affects the tension reading, since by bending
>the spoke into a curve the measurement raises the spoke tension.
>Friction and binding can also play a part depending on the design.
>
>> In a small span, the greater bending resistance of the thicker
>> spoke means that the same deflection requires more force against
>> greater tension than with a thinner spoke.
>>
>> The same thing is true when the spoke is made of different
>> materials.
>>
>> That's why the DT Swiss tables show different tensions for the
>> same deflection for spokes of different thickness and material.
>
><snip> Umm, Carl? Duh.
>
>Let's go back to what I wrote: "I zero out my tensiometer before
>use to reduce the measurement error as much as possible." Let's
>emphasize that "as much as possible" part. As a person
>professionally devoted to the use of the English language, I am sure
>you understand the meaning "as much as possible." I have long
>understood that zeroing out my tensiometer only reduces the error of
>measurement, it does not eliminate it.

Dear Tim,

I think that you missed the point again because you were too busy
explaining how you didn't.

OK, Carl, have it your way.

Quoted message said:

Jim Beam's point, easily confirmed by reference to tables for any
major micrometer-style spoke tension gauge, is that a 2mm spoke will
deflect a different distance than a 1.8 mm spoke under the same
deflection force because the different bending stiffness of the two
spokes.

Yes.

Quoted message said:

The same is true of spokes with the same dimensions made of similar
materials because the different materials have different bending
strengths.

Yes.

Quoted message said:

Consider a straight-gauge 2.0 mm spoke.

OK.

Quoted message said:

If it's made of stainless steel, the second column of the DT Swiss
table shows that a deflection of 1.76 mm means a spoke tension of 600
newtons.

OK.

Quoted message said:

If it's made of titanium, the last column of the DT Swiss table shows
that a deflection of 1.75 mm means a spoke tension of 700 newtons.

OK.

Quoted message said:

Read across the table at the bottom at any level, and you'll see that
the same spoke tension produces different deflection, according to
the spoke material and cross-section.

http://www.dtswiss.com/data/files/MAN_EN_51202133804.pdf

Is there something in this that you think is mysterious?

Quoted message said:

Before explaining again how right you are, see if you can summarize
the point that I'm saying you've missed.

No, thanks, Carl. I'm not really interested in passing an English test
at this stage of my life, nor do I need your passing grade for my life
to be complete. Feel free to believe that I understand, or to
disbelieve.

Dear Tim,

I think that you may understand now.

You didn't seem to understand before.

My understanding has not changed.

Tim McNamara said:

In article <[email hidden]>,

Quoted message said:

Tim McNamara said:

In article <[email hidden]>,
[email hidden] wrote:

> On Sat, 17 Feb 2007 17:09:03 -0600, Tim McNamara
> <[email hidden]> wrote:
>
> >In article <[email hidden]>,
> > [email hidden] wrote:
> >
> >> On Sat, 17 Feb 2007 09:38:24 -0600, Tim McNamara
> >> <[email hidden]> wrote:
> >>
> >> >In article <[email hidden]>,
> >> > jim beam <[email hidden]> wrote:
> >> >
> >> >> Tim McNamara wrote:
> >> >> > In article <[email hidden]>,
> >> >> > jim beam <[email hidden]> wrote:
> >> >> >
> >> >> >> Tim McNamara wrote: <snip [censored]>
> >> >> >>> Apparently the same problems apply to metallurgical
> >> >> >>> education.
> >> >> >> really? so why is it poor old jimmy beam, the uneducated
> >> >> >> one, that has to ask questions about a long time "peer
> >> >> >> reviewed" bible - "the bicycle wheel"? if y'all are so
> >> >> >> damned educated, smart and engineering professorial, how
> >> >> >> come y'all didn't figure out:
> >> >> >>
> >> >> >> 1. that the tensiometer math doesn't take account of spoke
> >> >> >> gauge?
> >> >> >
> >> >> > Given that Jobst has commented on this in the newsgroup when
> >> >> > discussing the shortcomings in tensiometer design and usage,
> >> >> > it seems that you are not in fact the only one.
> >> >>
> >> >> after i brought it up. but that's not the point. the point
> >> >> is, the other so-called "engineers" here haven't bothered to
> >> >> read or think about this stuff. nor did other self-appointed
> >> >> "experts". either they read it and decided it wasn't worth the
> >> >> hassle since jobst is always /so/ hostile to comment. or it
> >> >> was missed. did /you/ spot it? [rhetorical]
> >> >
> >> >Don't break your arm patting yourself on the back, jim. As for
> >> >whether I would have spotted it, the answer is actually "yes."
> >> >See, back when I was in school, I was taught to zero out
> >> >measurement tools whenever possible. I zero out my tensiometer
> >> >before use to reduce the measurement error as much as possible.
> >> >Been doing it for years before you started posting here, because
> >> >it was so bloody obvious.
> >>
> >> [snip]
> >>
> >> Dear Tim,
> >>
> >> Again, you've misunderstood the point.
> >
> >Carl, I did understand the point. But thank you for your concern.
> >
> >> Even after you zero the measuring device, the thickness of the
> >> spoke affects the tension reading.
> >
> >The bending stiffness of the spoke under no tension affects the
> >reading as does the diameter of the spoke. And the force used by
> >the tensiometer also affects the tension reading, since by bending
> >the spoke into a curve the measurement raises the spoke tension.
> >Friction and binding can also play a part depending on the design.
> >
> >> In a small span, the greater bending resistance of the thicker
> >> spoke means that the same deflection requires more force against
> >> greater tension than with a thinner spoke.
> >>
> >> The same thing is true when the spoke is made of different
> >> materials.
> >>
> >> That's why the DT Swiss tables show different tensions for the
> >> same deflection for spokes of different thickness and material.
> >
> ><snip> Umm, Carl? Duh.
> >
> >Let's go back to what I wrote: "I zero out my tensiometer before
> >use to reduce the measurement error as much as possible." Let's
> >emphasize that "as much as possible" part. As a person
> >professionally devoted to the use of the English language, I am sure
> >you understand the meaning "as much as possible." I have long
> >understood that zeroing out my tensiometer only reduces the error of
> >measurement, it does not eliminate it.
>
> Dear Tim,
>
> I think that you missed the point again because you were too busy
> explaining how you didn't.

OK, Carl, have it your way.

> Jim Beam's point, easily confirmed by reference to tables for any
> major micrometer-style spoke tension gauge, is that a 2mm spoke will
> deflect a different distance than a 1.8 mm spoke under the same
> deflection force because the different bending stiffness of the two
> spokes.

Yes.

> The same is true of spokes with the same dimensions made of similar
> materials because the different materials have different bending
> strengths.

Yes.

> Consider a straight-gauge 2.0 mm spoke.

OK.

> If it's made of stainless steel, the second column of the DT Swiss
> table shows that a deflection of 1.76 mm means a spoke tension of 600
> newtons.

OK.

> If it's made of titanium, the last column of the DT Swiss table shows
> that a deflection of 1.75 mm means a spoke tension of 700 newtons.

OK.

> Read across the table at the bottom at any level, and you'll see that
> the same spoke tension produces different deflection, according to
> the spoke material and cross-section.
>
> http://www.dtswiss.com/data/files/MAN_EN_51202133804.pdf

Is there something in this that you think is mysterious?

> Before explaining again how right you are, see if you can summarize
> the point that I'm saying you've missed.

No, thanks, Carl. I'm not really interested in passing an English test
at this stage of my life, nor do I need your passing grade for my life
to be complete. Feel free to believe that I understand, or to
disbelieve.

Dear Tim,

I think that you may understand now.

You didn't seem to understand before.

My understanding has not changed.

Dear Tim,

Which of these comments in the current thread best describes your
understanding?

"In any event, the calibration curves for 1.8 and 2.0mm diameter
spokes with this instrument are close enough to ignore the
difference."

--Jobst Brandt

"Around the tensions of interest (~100kgF), it's about a 12kgF
difference between 2.0mm and 1.8mm spokes with the same measured
displacement. The difference between 1.8mm and 1.6mm spokes is about
another 10kgF."

--Luns Tee

http://groups.google.com/group/rec.bicycles.tech/msg/8ceb0ad42888be7c

Cheers,

Carl Fogel

In article said:

Joe Riel <[email hidden]> writes:

(1) T = 1/4*(F/h)*(L - 3*L0) where LO=sqrt(EI/T)

Quoted message said:

Solving (1) for T is a pain, since its a cubic.

My napkin from lunch tells me:

T = FL/(6h)*(1+cos(x))

where x=2/3*acos(-9/L*sqrt(3*h*EI/(FL)))

-G. Cardano (as subtle as it is useless)