Maintenance Manuals



On Tue, 09 Oct 2007 10:11:15 -0400, Peter Cole
<[email protected]> wrote:

[snip]

>No sarcasm, no condescension, just a frank opinion of his methods. We've
>discussed this at length before. Carl is always attempting to (dis)prove
>theory with actual measurements. The problem with this is it generally
>takes an even better grasp of theory just to set up the measurement. I
>don't mean to slam Carl, I appreciate the difficulty of what he's trying
>to do (I've worked in the precision measurement field) -- unfortunately,
>he often seems not to.


Dear Peter,

We're often at odds, but I think that you're doing a better job here
than I usually give you credit for.

In the same fashion, I don't mean to slam you. I appreciate that you
have considerable engineering skills and experience.

The problem that I see is that--and you're not alone in this--we on
RBT unfortunately tend to apply theory to a practical situation
without testing or even considering the possibility that our
theoretical, untested model may not include crucial real-world
factors, which by their very nature never how up in our purely
theoretical reasoning.

(We don't know what's wrong with our theories until reality rubs our
noses in our misunderstandings.)

Even more unfortunately, we then defend our theoretical position with
more theory and whatever ad hoc observations support us, which is more
debating than science.

(That's why we have the phrase "Back to the drawing board" to describe
what happens when theories are not tested.)

Here's about as plain and simple a bike example as I can think of,
where perfectly valid theory drew an obviously impractical conclusion:

http://groups.google.com/group/rec.bicycles.tech/msg/a14af7c4e0dc2fb0

When a closed chain is worn enough, you can easily invert it, despite
theory, turning it inside and out like a rubber band.

Similarly, I found to my surprise that the spoke tension on a cheap
MTB wheel dropped when I let the air out of the tire, instead of
rising as theory and even testing on 700c wheels showed it should do.

And I found that the contact patch refuses to expand or contract
nearly as much as RBT theory predicted when tire pressure is raised or
lowered. It turns out that a pressing on the outside of an inflated
canvas toroid is more complicated than a rigid steel piston rising or
falling in a rigid steel chamber.

My favorite non-bicycling example of theory blinding us to reality is
the Mpemba effect, where hot water freezes more quickly than cold
water, a result that still has no good theoretical explanation, but
which can be demonstrated with precision measurements--which aren't
actually necessary, since the effect is pronounced enough to be
well-known among practical folks who freeze things for a living.

Here the Mpemba effect is shown with precision measurements, the
bottom graph being hideously clear:

http://www.picotech.com/experiments/mpemba_effect/results.html

There are still web pages that insist that the Mpemba effect must be
due to poor test procedures, even though the original article
carefully eliminated the very objections raised, but more and more the
multiple explanations are complicated and uncertain:

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/freezhot.html#c3

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

The real lesson of the Mpemba effect was that it took a visiting
professor to take Mpemba seriously. Instead of telling Mpemba not to
waste time asking why hot water froze faster than cold water, since it
was obviously theoretically impossible, the professor said let's see
what happens and discovered that this bit of myth and lore was quite
true:

http://physicsworld.com/cws/article/print/24493

A sound theory by definition leads to a sound conclusion, but in the
real world things are often so complicated that describing the
situation takes more sound theories than we first imagine.

My vote is for testing and measuring, particularly when there are
disagreements. Squeezing spoke pairs, for example, has lots of
plausible theory and plenty of enthusiasts behind it, but we still
have no tests confirming that it prevents broken spokes, much less
demonstrating how.

Cheers,

Carl Fogel
 
In article <[email protected]>,
"[email protected]" <[email protected]> wrote:

> On Oct 6, 10:38 pm, [email protected] wrote:
>
> > Dear Spike,
> >
> > I'm sorry that you're not embarrassed by your behavior.
> >
> > What credibility do you expect when you first announce that you won't
> > believe anything that Jim Beam says, then announce that he's faking
> > photos, and later explain that you should have been "clearer and more
> > expansive"?

>
> Dear Carl,
>
> I don't care one way or another about jim beam's
> photograph and see no reason to doubt its veracity, but:
>
> http://groups.google.com/group/rec.bicycles.tech/browse_frm/thread/5c572766985
> 6726d/85ff7a01beb8e1e7#85ff7a01beb8e1e7
>
> You're in a fine position to lecture people about
> the rudeness of disbelieving photographic evidence
> on RBT.
>
> Ben


Ben: in the case of Carl's photo, much like a well-written mystery
story, the evidence was all there to be seen. He was being a terrible
tease, but he also came clean reasonably quickly (like, in the second
half of that message, which started with these stentences: "So much for
deceiving trusting readers as an object lesson. There are no hidden
flaws in what follows--at least no _deliberately_ hidden flaws.")

It's perhaps the case that like Carl, I've read a few too many works of
fiction, and especially a few too many mystery stories. We like literary
puzzles, and occasionally spring them on others.

But really, the technology here is decades and decades old. If you've
read Poe's "The Purloined Letter," you'll see that Carl hid the
devilishly deceptive spoke in plain sight. As you noted, the length
alone was a dead giveaway.

Now, if someone points out that a spoke doesn't look quite right, that's
one thing. If someone makes an erroneous claim of falsity, and then
won't back down in the face of considerable evidence of their own
wrongness, well, you can't be paying a terrible amount of attention to
such a person.

--
Ryan Cousineau [email protected] http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos
 
Ben C wrote:
> On 2007-10-09, [email protected] <[email protected]> wrote:
>> Ben C? writes:

> [...]
>>> I vaguely remember some big brass or copper-coloured things from my very
>>> first set of Mavics quite a few years ago. They were MA somethings,
>>> either 2 or 40 probably.

>> The Reflex is tubular and has sockets if you look on the Mavic web site.
>> I can't give you the URL because the spec's are under the main entry:
>>
>> http://www.mavic.com/road/

>
> OK, thanks. You can't give me a URL because their website is so crappy
> and based on Flash.
>
> But I went to products->rims->Reflex and could see what looked like the
> eyelets on the Open Pro. Unfortunately you can't get a decent look
> inside the box section to see them properly.
>
> The CXP-33's look a bit different and are described as "profiled
> eyelets" rather than as "double eyelets" which is the term they use for
> both the Reflex and the Open Pro.


open pros are double eyelet. jobst just likes to use "socket" because
he thinks it makes him look more "knowledgeable" so he can sell books.
if the rest of us say "double eyelet" like the manufacturers do, then i
think we'll be just fine. it's like jobst insists on calling all butted
spokes "swaged", even though he's wrong because some are instead drawn
and others ground.
 
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> [email protected] wrote:
>>>> On Mon, 08 Oct 2007 09:58:47 -0400, Peter Cole
>>>> <[email protected]> wrote:
>>>>
>>>>> [email protected] wrote:
>>>>>> On Sat, 06 Oct 2007 16:29:52 -0400, Peter Cole
>>>>>> <[email protected]> wrote:
>>>>>>> I have no doubt that spokes could be tensioned to 175kg, just
>>>>>>> that it's unlikely that Jobst's method would get you there -- for
>>>>>>> all the reasons I previously mentioned.
>>>>>> Dear Peter,
>>>>>>
>>>>>> If the spoke is at 175 kgf with a presumably inflated and
>>>>>> constricting
>>>>>> tire in place, then it was presumably close to 190 kgf when built
>>>>>> bare
>>>>>> on a truing stand.
>>>>>> The rim looks fairly ordinary, neither deep section nor low spoke
>>>>>> count:
>>>>>>
>>>>>> http://www.flickr.com/photos/38636024@N00/1498602218/
>>>>>>
>>>>>> If the spokes are indeed all tensioned to about 175~190 kgf, why
>>>>>> wouldn't Jobst's practical method for determining the highest
>>>>>> practical tension work?
>>>>>> Raise tension until the wheel goes out of true when spoke pairs are
>>>>>> squeezed, then back off half a turn and re-true.
>>>>>>
>>>>>> If you raise the tension well beyond that level, the wheel is
>>>>>> presumably going to pop out of true shortly after you start riding
>>>>>> it.
>>>>> I don't know what final tension Jobst's method would give for that
>>>>> rim.
>>>>>
>>>>> My only point is that I am skeptical that his method was followed
>>>>> accurately, since the final tension would have to be much lower
>>>>> than the peak tension (1/2 turn off all nipples) and the
>>>>> combination of peak tension and the stress relief "squeeze" should
>>>>> have raised the tension in the squeezed spokes well above failure.
>>>>> Something doesn't add up.
>>>>
>>>> Dear Peter,
>>>>
>>>> How much does a half turn reduction, followed by re-truing change what
>>>> tension?
>>>
>>> A half turn is about 30kg.

>>
>> spoke thread is 56tpi, correct?
>>
>> that's 0.45mm per thread.
>>
>> 1/2 turn = 0.23mm elastic elongation.
>>
>> if elongation = stress x length / modulus, then
>>
>> elongation x modulus / length = stress.
>>
>> 0.23mm x 200,000Nmm^-2 / 294mm = 156N
>>
>> 156N = ~16kgf tension increase for half a turn.

>
> You forgot to multiply for the cross section area (to convert stress to
> force), so you're off by a factor of about 2.5 for a 1.8mm diameter
> (2.0mm butted) spoke.


yup, you're right. so that makes it 40kgf, not 30kgf.


>
>
>>>> What do you think is the "peak" tension and how do you calculate it
>>>> for the wheel in the photograph, since you say that you don't know
>>>> what final tension Jobst's method would give for that rim?
>>>
>>> If the final tension is >175kg, + 1/2 turn = >205kg, plus whatever
>>> the inflated tire is dropping, perhaps 10kg anyway, so >215kg.
>>> According to Jobst's book, 1.8mm spokes let go at 250,

>>
>> eh? they don't "let go", they simply yield.

>
> There are multiple definitions of "yield", if you want to specify 0.2%
> plastic strain, I'm OK with that.


good. but how does that reconcile with "let go"???

>
>>> I'd think a big guy like jb could easily squeeze another 35kg.

>>
>> not if he's following written instruction and is not subject to peter
>> cole math or confusion about yield.

>
> I don't think my "math" is the problem, nor my "confusion" about yield.


how about you start with defining "let go", then progress onto how that
becomes simply yield?
 
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> [email protected] wrote:
>>>> On Mon, 08 Oct 2007 16:24:53 -0400, Peter Cole
>>>> <[email protected]> wrote:
>>>>
>>>>> [email protected] wrote:
>>>>>> On Mon, 08 Oct 2007 09:35:41 -0400, Peter Cole
>>>>>> <[email protected]> wrote:
>>>>>>
>>>>>>> jim beam wrote:
>>>>>>>> Peter Cole wrote:
>>>>>>>>> [email protected] wrote:
>>>>>>>>>
>>>>>>>>>> Dear Peter,
>>>>>>>>>>
>>>>>>>>>> Whatever you two are arguing about, the numbers on the Park
>>>>>>>>>> tension
>>>>>>>>>> gauge read in increments of 5.
>>>>>>>>>> Though fuzzy, the inset shows the needle pointing to about 26,
>>>>>>>>>> which
>>>>>>>>>> is the extreme high end of the Park table calibration for a round
>>>>>>>>>> steel 1.8 mm spoke, about 175 kgf, or ~385 pounds of tension.
>>>>>>>>> OK, thanks Carl.
>>>>>>>>>
>>>>>>>>> I have no doubt that spokes could be tensioned to 175kg,
>>>>>>>> ridiculous. that wasn't the case when you declared it
>>>>>>>> "impossible".
>>>>>>> No, I said that to end up with ">175", you had to tension to at
>>>>>>> least 210 (because you back off all nipples 1/2 turn), and that
>>>>>>> at 210, the 50% increase in spoke tension caused by squeezing the
>>>>>>> spokes together would take you to plastic, if not ultimate, yield
>>>>>>> for those spokes.
>>>>>>>
>>>>>>> 175 isn't impossible, getting there with Jobst's method is.
>>>>>>>
>>>>>>>>> just that it's unlikely that Jobst's method would get you there
>>>>>>>>> -- for all the reasons I previously mentioned.
>>>>>>>> hypocritical bullshitter.
>>>>>>> Whatever. Your explanation still doesn't hold water.
>>>>>> Dear Peter,
>>>>>>
>>>>>> How do you determine that a half turn on all spokes will raise
>>>>>> tension
>>>>>> from 175 kgf to 210 kgf?
>>>>> Pitch of spoke thread, spoke elasticity.
>>>>>
>>>>>> It may be in the thread, but it's far too large to hunt through.
>>>>>>
>>>>>> Incidentally, should I tension a spoke in my pipe vise rig to 175
>>>>>> kgf,
>>>>>> squeeze it and see if it takes things to plastic yield?
>>>>> Knock yourself out.
>>>>>
>>>>>
>>>>>> Have you ever managed to squeeze a spoke to plastic yield in an
>>>>>> actual
>>>>>> wheel, whose rim deforms noticeably when you squeeze spoke pairs?
>>>>> Nope, never tried.
>>>>>
>>>>>
>>>>>> You can check the rim deformation quite easily by taping a spoke flat
>>>>>> to the brake surface so that it sticks out at a tangent to the wheel.
>>>>>> When you squeeze the spoke pairs, the end of the spoke wiggles.
>>>>> Whatever turns you on.
>>>>
>>>> Dear Peter,
>>>>
>>>> Can you actually stretch two spokes on a bicycle rim by squeezing them
>>>> together?
>>>
>>> As I said above, I never have tried.

>>
>> well, well, well - the "engineer" with absolutely no interest in doing
>> anything other than opine.

>
> I don't have the equipment to do such a test. I'd need to measure (even
> to detect the largest definition of yield -- 0.2% plastic) half a mm
> over 300mm. I don't see the point, anyway.


er, the point is that you have an opinion, and you argue the toss, but
you don't back it up with fact.


>
>>>> I don't think that anyone has ever reported this on RBT, so you can be
>>>> the first if you can do it.
>>>
>>> I've never tried to tension a wheel to >210kg. According to Jobst's
>>> tables that would get me very close, if not actually at, the plastic
>>> region.

>>
>> do you use 1.6mm 30-year old spokes? why not use dt swiss spokes that
>> has a yield of 1100Nmm^-2? a standard butted 1.8mm spoke gives you
>> ~280kgf.

>
> I assume you mean something like DT "Competition" spokes. I also assume
> you're using "1.8mm" the way Jobst & DT do to indicate a spoke with
> 1.8mm ends and a 1.6mm middle.


no, i mean 1.8mm, like 1.8mm in the butted section. just like you
yourself assumed in your earlier post.


>
> The standard 0.2% offset yield seems to be around 2100N from the curves
> in Jobst's book made from actual measurements on DT spokes of that type.


ok...

>
> If you mean 2.0mm butted (1.8mm middle), the 0.2% yield is still only
> around 2500N (as best I can read the curve).


ok... oh, and how close to that yield point is a measured tension of
175kgf?


>
> Where does your "1100Nmm^-2" come from? I didn't see it at the DT site.


not now, but they had a different site with yield data on it not so long
ago. why don't you try the wayback machine?


>
>
>>>> I expect that the rims will just deform sideways and that the most
>>>> that you'll manage is to put a faint but permanent bend in the middle
>>>> of the spoke.
>>>>
>>>> That's all that I ever managed in extensive testing.
>>>
>>> That doesn't surprise me.

>>
>> sarcastic condescension? peter cole? never!

>
> No sarcasm, no condescension, just a frank opinion of his methods. We've
> discussed this at length before. Carl is always attempting to (dis)prove
> theory with actual measurements.


no, he's simply testing the assertions for which no data has been
provided. just like your own careful and meticulous... oh, you've
never done anything. my mistake.


> The problem with this is it generally
> takes an even better grasp of theory just to set up the measurement. I
> don't mean to slam Carl,


er, except that you do.


> I appreciate the difficulty of what he's trying
> to do (I've worked in the precision measurement field)


then you should be able to contribute!!!!!!!!!!!!!!!

oh, wait, than might mean data that contradicts presumption. my bad.

> -- unfortunately,
> he often seems not to.


********.
 
On Wed, 10 Oct 2007 02:12:52 GMT, Ryan Cousineau <[email protected]>
wrote:

>In article <[email protected]>,
> "[email protected]" <[email protected]> wrote:
>
>> On Oct 6, 10:38 pm, [email protected] wrote:
>>
>> > Dear Spike,
>> >
>> > I'm sorry that you're not embarrassed by your behavior.
>> >
>> > What credibility do you expect when you first announce that you won't
>> > believe anything that Jim Beam says, then announce that he's faking
>> > photos, and later explain that you should have been "clearer and more
>> > expansive"?

>>
>> Dear Carl,
>>
>> I don't care one way or another about jim beam's
>> photograph and see no reason to doubt its veracity, but:
>>
>> http://groups.google.com/group/rec.bicycles.tech/browse_frm/thread/5c572766985
>> 6726d/85ff7a01beb8e1e7#85ff7a01beb8e1e7
>>
>> You're in a fine position to lecture people about
>> the rudeness of disbelieving photographic evidence
>> on RBT.
>>
>> Ben

>
>Ben: in the case of Carl's photo, much like a well-written mystery
>story, the evidence was all there to be seen. He was being a terrible
>tease, but he also came clean reasonably quickly (like, in the second
>half of that message, which started with these stentences: "So much for
>deceiving trusting readers as an object lesson. There are no hidden
>flaws in what follows--at least no _deliberately_ hidden flaws.")
>
>It's perhaps the case that like Carl, I've read a few too many works of
>fiction, and especially a few too many mystery stories. We like literary
>puzzles, and occasionally spring them on others.
>
>But really, the technology here is decades and decades old. If you've
>read Poe's "The Purloined Letter," you'll see that Carl hid the
>devilishly deceptive spoke in plain sight. As you noted, the length
>alone was a dead giveaway.
>
>Now, if someone points out that a spoke doesn't look quite right, that's
>one thing. If someone makes an erroneous claim of falsity, and then
>won't back down in the face of considerable evidence of their own
>wrongness, well, you can't be paying a terrible amount of attention to
>such a person.


Dear Ryan,

If anything, I was rather more explicit than Mark Twain's famous
report of a petrified man, with its careful description of the
petrified man pointing to his winking left eye with one hand and
thumbing his nose at the world with the other:

http://www.twainquotes.com/18621004t.html

After all, Twain included no picture and said nothing about what his
petrified man was doing.

After calculating that the spoke's displacement indicated that its
tension must have risen 195 pounds, I wrote:

| But despite my faultless theory and careful measurements, a
| small correction seems to be needed to get the correct spoke
| tension:
|
| http://i18.tinypic.com/30c6a3c.jpg
|
| :)
|
| A real wheel may have a few smaller confounding factors hidden
| in it that aren't as easily revealed."

http://groups.google.com/group/rec.bicycles.tech/msg/c501e003f9d0c04f

The picture shows the thick, short motorcycle spoke lying loose and
obviously untensioned across the jaws the vise (spread 4.54 inches
apart, as I conscientiously noted), despite the carefully measured
weight hanging from its center.

Maybe a bigger smiley was needed?

Cheers,

Carl Fogel
 
[email protected] wrote:
> On Tue, 09 Oct 2007 10:11:15 -0400, Peter Cole
> <[email protected]> wrote:
>
> [snip]
>
>> No sarcasm, no condescension, just a frank opinion of his methods. We've
>> discussed this at length before. Carl is always attempting to (dis)prove
>> theory with actual measurements. The problem with this is it generally
>> takes an even better grasp of theory just to set up the measurement. I
>> don't mean to slam Carl, I appreciate the difficulty of what he's trying
>> to do (I've worked in the precision measurement field) -- unfortunately,
>> he often seems not to.

>
> Dear Peter,
>
> We're often at odds, but I think that you're doing a better job here
> than I usually give you credit for.


That's not saying much, if anything, but do go on.


> In the same fashion, I don't mean to slam you. I appreciate that you
> have considerable engineering skills and experience.
>
> The problem that I see is that--and you're not alone in this--we on
> RBT unfortunately tend to apply theory to a practical situation
> without testing or even considering the possibility that our
> theoretical, untested model may not include crucial real-world
> factors, which by their very nature never how up in our purely
> theoretical reasoning.


Sure, the selected model may not be a good match to reality, or it may
be parameterized wrong. That happens, but what is much more frequent is
arguments based on a lack of understanding of the model or its
underlying science.


> (We don't know what's wrong with our theories until reality rubs our
> noses in our misunderstandings.)
>
> Even more unfortunately, we then defend our theoretical position with
> more theory and whatever ad hoc observations support us, which is more
> debating than science.
>
> (That's why we have the phrase "Back to the drawing board" to describe
> what happens when theories are not tested.)


If you say so, but I'm not finding your argument convincing.

> Here's about as plain and simple a bike example as I can think of,
> where perfectly valid theory drew an obviously impractical conclusion:
>
> http://groups.google.com/group/rec.bicycles.tech/msg/a14af7c4e0dc2fb0
>
> When a closed chain is worn enough, you can easily invert it, despite
> theory, turning it inside and out like a rubber band.


Sure, but it was a sucker's bet, given the amount of wear on the chain.


> Similarly, I found to my surprise that the spoke tension on a cheap
> MTB wheel dropped when I let the air out of the tire, instead of
> rising as theory and even testing on 700c wheels showed it should do.


Again, the "prediction" had to include casing angle, there's no promise
that inflation will compress of expand the rim without it.


> And I found that the contact patch refuses to expand or contract
> nearly as much as RBT theory predicted when tire pressure is raised or
> lowered. It turns out that a pressing on the outside of an inflated
> canvas toroid is more complicated than a rigid steel piston rising or
> falling in a rigid steel chamber.


I don't know what "RBT theory" is. The weight of a bike and rider is
borne by the sidewall, which has a complex deflection -- how that
translates into footprint is not simple.

> My favorite non-bicycling example of theory blinding us to reality is
> the Mpemba effect,


Interesting, but no news & OT.

> A sound theory by definition leads to a sound conclusion, but in the
> real world things are often so complicated that describing the
> situation takes more sound theories than we first imagine.


That comes as no news to an engineer. That's pretty much what our
professional lives are all about.


> My vote is for testing and measuring, particularly when there are
> disagreements. Squeezing spoke pairs, for example, has lots of
> plausible theory and plenty of enthusiasts behind it, but we still
> have no tests confirming that it prevents broken spokes, much less
> demonstrating how.


If something can't be proved, it's religion, by definition. To conduct a
valid experiment, you must prove the experiment. That's the hard part,
both in design and realization.
 
jim beam wrote:

> how about you start with defining "let go", then progress onto how that
> becomes simply yield?



I think we all know what that means.
 
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>> Peter Cole wrote:
>>>> [email protected] wrote:

Dear Peter,
>>>>>
>>>>> Can you actually stretch two spokes on a bicycle rim by squeezing them
>>>>> together?
>>>>
>>>> As I said above, I never have tried.
>>>
>>> well, well, well - the "engineer" with absolutely no interest in
>>> doing anything other than opine.

>>
>> I don't have the equipment to do such a test. I'd need to measure
>> (even to detect the largest definition of yield -- 0.2% plastic) half
>> a mm over 300mm. I don't see the point, anyway.

>
> er, the point is that you have an opinion, and you argue the toss, but
> you don't back it up with fact.


No, unlike Carl, I know when I don't have the setup to do a measurement.

>>> a standard butted 1.8mm spoke gives
>>> you ~280kgf.

>>
>> I assume you mean something like DT "Competition" spokes. I also
>> assume you're using "1.8mm" the way Jobst & DT do to indicate a spoke
>> with 1.8mm ends and a 1.6mm middle.

>
> no, i mean 1.8mm, like 1.8mm in the butted section. just like you
> yourself assumed in your earlier post.


OK, as usual, adopt your own convention, but don't get testy when people
misunderstand you. Isn't "1.8mm butted" redundant?

Actually, I didn't assume that in an earlier post, that's why I got
30kg, not 40. (force = stress times *area*, remember?)


>> The standard 0.2% offset yield seems to be around 2100N from the
>> curves in Jobst's book made from actual measurements on DT spokes of
>> that type.

>
> ok...
>
>>
>> If you mean 2.0mm butted (1.8mm middle), the 0.2% yield is still only
>> around 2500N (as best I can read the curve).

>
> ok... oh, and how close to that yield point is a measured tension of
> 175kgf?


">175" + 40 + 10 (tire) = > 225, plus a hard hand squeeze = ?? You tell me.


>> Where does your "1100Nmm^-2" come from? I didn't see it at the DT site.

>
> not now, but they had a different site with yield data on it not so long
> ago. why don't you try the wayback machine?


It's your claim, you prove it.
 
On Oct 10, 3:33 pm, Peter Cole <[email protected]> wrote:
>
> article on aluminum, alloys heat treatmentshttp://www.bikepro.com/products/metals/alum.html


Golly, don't let jim beam see that!

It contains this paragraph:

"The ingots can be remelted to make cast aluminum products, using
various methods of casting including (in the bike industry), die
casting where molten aluminum is injected under high pressure into the
cavity of a metal die. Aluminum alloys have a reasonably low melting
point which makes a dense, fine-grain surface structure with excellent
wear and fatigue properties when die cast. Also permanent mold casting
may be used, which uses a metal mold repeatedly for producing many
castings of the same form. These casting techniques are the way many
crank arms, pedal bodies, hub shells, seatpost head pieces, stems, and
some headset parts are commercially made in volume."

When I said similar things, he switched to full, furious insult
mode.

- Frank Krygowski
 
Peter Cole wrote:
> jim beam wrote:
>
>> how about you start with defining "let go", then progress onto how
>> that becomes simply yield?

>
>
> I think we all know what that means.


yes, it means peter cole is wriggling and squirming because he was
trying to say that spokes fracture when all they do is yield.
 
Peter Cole wrote:
> [email protected] wrote:
>> On Tue, 09 Oct 2007 10:11:15 -0400, Peter Cole
>> <[email protected]> wrote:
>>
>> [snip]
>>
>>> No sarcasm, no condescension, just a frank opinion of his methods.
>>> We've discussed this at length before. Carl is always attempting to
>>> (dis)prove theory with actual measurements. The problem with this is
>>> it generally takes an even better grasp of theory just to set up the
>>> measurement. I don't mean to slam Carl, I appreciate the difficulty
>>> of what he's trying to do (I've worked in the precision measurement
>>> field) -- unfortunately, he often seems not to.

>>
>> Dear Peter,
>>
>> We're often at odds, but I think that you're doing a better job here
>> than I usually give you credit for.

>
> That's not saying much, if anything, but do go on.
>
>
>> In the same fashion, I don't mean to slam you. I appreciate that you
>> have considerable engineering skills and experience.
>>
>> The problem that I see is that--and you're not alone in this--we on
>> RBT unfortunately tend to apply theory to a practical situation
>> without testing or even considering the possibility that our
>> theoretical, untested model may not include crucial real-world
>> factors, which by their very nature never how up in our purely
>> theoretical reasoning.

>
> Sure, the selected model may not be a good match to reality, or it may
> be parameterized wrong. That happens, but what is much more frequent is
> arguments based on a lack of understanding of the model or its
> underlying science.


<snip ****>

you said it!!! "extruding only applies shear and compression forces,
which are unlikely to produce anisotropy"

damn, that is a classic of not understanding the underlying science!!!
 
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> jim beam wrote:
>>>> Peter Cole wrote:
>>>>> [email protected] wrote:

> Dear Peter,
>>>>>>
>>>>>> Can you actually stretch two spokes on a bicycle rim by squeezing
>>>>>> them
>>>>>> together?
>>>>>
>>>>> As I said above, I never have tried.
>>>>
>>>> well, well, well - the "engineer" with absolutely no interest in
>>>> doing anything other than opine.
>>>
>>> I don't have the equipment to do such a test. I'd need to measure
>>> (even to detect the largest definition of yield -- 0.2% plastic) half
>>> a mm over 300mm. I don't see the point, anyway.

>>
>> er, the point is that you have an opinion, and you argue the toss, but
>> you don't back it up with fact.

>
> No, unlike Carl, I know when I don't have the setup to do a measurement.


maybe not from your sofa, but if you want to contribute to this
"debate", [as opposed to dropping sublime ignorance-bombs], get up off
your lardy lazy ass, go into the garage and get working with the
instruments.


>
>>>> a standard butted 1.8mm spoke gives you ~280kgf.
>>>
>>> I assume you mean something like DT "Competition" spokes. I also
>>> assume you're using "1.8mm" the way Jobst & DT do to indicate a spoke
>>> with 1.8mm ends and a 1.6mm middle.

>>
>> no, i mean 1.8mm, like 1.8mm in the butted section. just like you
>> yourself assumed in your earlier post.

>
> OK, as usual, adopt your own convention, but don't get testy when people
> misunderstand you. Isn't "1.8mm butted" redundant?


er, there are 1.8mm straight gauge spokes. and the majority of butted
spokes sold are 2.0/1.8/2.0mm, so it's hardly my own "convention".


>
> Actually, I didn't assume that in an earlier post, that's why I got
> 30kg, not 40. (force = stress times *area*, remember?)


how convenient!


>
>
>>> The standard 0.2% offset yield seems to be around 2100N from the
>>> curves in Jobst's book made from actual measurements on DT spokes of
>>> that type.

>>
>> ok...
>>
>>>
>>> If you mean 2.0mm butted (1.8mm middle), the 0.2% yield is still only
>>> around 2500N (as best I can read the curve).

>>
>> ok... oh, and how close to that yield point is a measured tension of
>> 175kgf?

>
> ">175" + 40 + 10 (tire) = > 225, plus a hard hand squeeze = ?? You tell me.


i don't need to tell you - carl's done it for your lazy ass already.
and you have the wrong sign for tire pressure - it /reduces/ spoke
tension, not increases it.


>
>
>>> Where does your "1100Nmm^-2" come from? I didn't see it at the DT site.

>>
>> not now, but they had a different site with yield data on it not so
>> long ago. why don't you try the wayback machine?

>
> It's your claim, you prove it.


no, /you/ do it because /you/ don't agree. my figures are already in
the archive, and are corroborated by carl fogel from the same dt website
i used. /you/ get your lazy ass searching the archive and checking the
wayback machine. mr. "extruding only applies shear and compression
forces, which are unlikely to produce anisotropy".
 
[email protected] wrote:
> On Oct 10, 3:33 pm, Peter Cole <[email protected]> wrote:
>> article on aluminum, alloys heat treatmentshttp://www.bikepro.com/products/metals/alum.html

>
> Golly, don't let jim beam see that!
>
> It contains this paragraph:
>
> "The ingots can be remelted to make cast aluminum products, using
> various methods of casting including (in the bike industry), die
> casting where molten aluminum is injected under high pressure into the
> cavity of a metal die. Aluminum alloys have a reasonably low melting
> point which makes a dense, fine-grain surface structure with excellent
> wear and fatigue properties when die cast. Also permanent mold casting
> may be used, which uses a metal mold repeatedly for producing many
> castings of the same form. These casting techniques are the way many
> crank arms, pedal bodies, hub shells, seatpost head pieces, stems, and
> some headset parts are commercially made in volume."
>
> When I said similar things, he switched to full, furious insult
> mode.
>
> - Frank Krygowski
>
 
[email protected] wrote:
> On Oct 10, 3:33 pm, Peter Cole <[email protected]> wrote:
>> article on aluminum, alloys heat treatmentshttp://www.bikepro.com/products/metals/alum.html

>
> Golly, don't let jim beam see that!
>
> It contains this paragraph:
>
> "The ingots can be remelted to make cast aluminum products, using
> various methods of casting including (in the bike industry), die
> casting where molten aluminum is injected under high pressure into the
> cavity of a metal die. Aluminum alloys have a reasonably low melting
> point which makes a dense, fine-grain surface structure with excellent
> wear and fatigue properties when die cast. Also permanent mold casting
> may be used, which uses a metal mold repeatedly for producing many
> castings of the same form. These casting techniques are the way many
> crank arms, pedal bodies, hub shells, seatpost head pieces, stems, and
> some headset parts are commercially made in volume."
>
> When I said similar things, he switched to full, furious insult
> mode.
>
> - Frank Krygowski
>


so that's why you made your mistake? does this paragraph contain the
word "thixoforming" or "melt casting"? no? so how could it be that
manufacturers actually use those process and not simple "die casting"
then? [rhetorical]

bottom line, that article is hugely simplified. just because
thixoforming and extrusion are not named doesn't mean they don't exist
or are not used.
 
In article
<[email protected]>,
[email protected] wrote:

> On Oct 10, 3:33 pm, Peter Cole <[email protected]> wrote:
> >
> > article on aluminum, alloys heat treatmentshttp://www.bikepro.com/products/metals/alum.html

>
> Golly, don't let jim beam see that!
>
> It contains this paragraph:
>
> "The ingots can be remelted to make cast aluminum products, using
> various methods of casting including (in the bike industry), die
> casting where molten aluminum is injected under high pressure into the
> cavity of a metal die. Aluminum alloys have a reasonably low melting
> point which makes a dense, fine-grain surface structure with excellent
> wear and fatigue properties when die cast. Also permanent mold casting
> may be used, which uses a metal mold repeatedly for producing many
> castings of the same form. These casting techniques are the way many
> crank arms, pedal bodies, hub shells, seatpost head pieces, stems, and
> some headset parts are commercially made in volume."
>
> When I said similar things, he switched to full, furious insult
> mode.


You owe it to yourself to find that message and reply to it
with this paragraph.

--
Michael Press
 
Michael Press wrote:
> In article
> <[email protected]>,
> [email protected] wrote:
>
>> On Oct 10, 3:33 pm, Peter Cole <[email protected]> wrote:
>>> article on aluminum, alloys heat treatmentshttp://www.bikepro.com/products/metals/alum.html

>> Golly, don't let jim beam see that!
>>
>> It contains this paragraph:
>>
>> "The ingots can be remelted to make cast aluminum products, using
>> various methods of casting including (in the bike industry), die
>> casting where molten aluminum is injected under high pressure into the
>> cavity of a metal die. Aluminum alloys have a reasonably low melting
>> point which makes a dense, fine-grain surface structure with excellent
>> wear and fatigue properties when die cast. Also permanent mold casting
>> may be used, which uses a metal mold repeatedly for producing many
>> castings of the same form. These casting techniques are the way many
>> crank arms, pedal bodies, hub shells, seatpost head pieces, stems, and
>> some headset parts are commercially made in volume."
>>
>> When I said similar things, he switched to full, furious insult
>> mode.

>
> You owe it to yourself to find that message and reply to it
> with this paragraph.
>

why? finding a source of "corroborative" omission is hardly an
achievement worthy of re-post - two omissions are still an omission.
 
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>> Peter Cole wrote:
>>>> jim beam wrote:
>>>>> Peter Cole wrote:
>>>>>> [email protected] wrote:

>> Dear Peter,
>>>>>>>
>>>>>>> Can you actually stretch two spokes on a bicycle rim by squeezing
>>>>>>> them
>>>>>>> together?
>>>>>>
>>>>>> As I said above, I never have tried.
>>>>>
>>>>> well, well, well - the "engineer" with absolutely no interest in
>>>>> doing anything other than opine.
>>>>
>>>> I don't have the equipment to do such a test. I'd need to measure
>>>> (even to detect the largest definition of yield -- 0.2% plastic)
>>>> half a mm over 300mm. I don't see the point, anyway.
>>>
>>> er, the point is that you have an opinion, and you argue the toss,
>>> but you don't back it up with fact.

>>
>> No, unlike Carl, I know when I don't have the setup to do a measurement.

>
> maybe not from your sofa, but if you want to contribute to this
> "debate", [as opposed to dropping sublime ignorance-bombs], get up off
> your lardy lazy ass, go into the garage and get working with the
> instruments.
>
>
>>
>>>>> a standard butted 1.8mm spoke gives you ~280kgf.
>>>>
>>>> I assume you mean something like DT "Competition" spokes. I also
>>>> assume you're using "1.8mm" the way Jobst & DT do to indicate a
>>>> spoke with 1.8mm ends and a 1.6mm middle.
>>>
>>> no, i mean 1.8mm, like 1.8mm in the butted section. just like you
>>> yourself assumed in your earlier post.

>>
>> OK, as usual, adopt your own convention, but don't get testy when
>> people misunderstand you. Isn't "1.8mm butted" redundant?

>
> er, there are 1.8mm straight gauge spokes. and the majority of butted
> spokes sold are 2.0/1.8/2.0mm, so it's hardly my own "convention".
>
>
>>
>> Actually, I didn't assume that in an earlier post, that's why I got
>> 30kg, not 40. (force = stress times *area*, remember?)

>
> how convenient!
>
>
>>
>>
>>>> The standard 0.2% offset yield seems to be around 2100N from the
>>>> curves in Jobst's book made from actual measurements on DT spokes of
>>>> that type.
>>>
>>> ok...
>>>
>>>>
>>>> If you mean 2.0mm butted (1.8mm middle), the 0.2% yield is still
>>>> only around 2500N (as best I can read the curve).
>>>
>>> ok... oh, and how close to that yield point is a measured tension of
>>> 175kgf?

>>
>> ">175" + 40 + 10 (tire) = > 225, plus a hard hand squeeze = ?? You
>> tell me.

>
> i don't need to tell you - carl's done it for your lazy ass already. and
> you have the wrong sign for tire pressure - it /reduces/ spoke tension,
> not increases it.
>
>
>>
>>
>>>> Where does your "1100Nmm^-2" come from? I didn't see it at the DT site.
>>>
>>> not now, but they had a different site with yield data on it not so
>>> long ago. why don't you try the wayback machine?

>>
>> It's your claim, you prove it.

>
> no, /you/ do it because /you/ don't agree. my figures are already in
> the archive, and are corroborated by carl fogel from the same dt website
> i used. /you/ get your lazy ass searching the archive and checking the
> wayback machine. mr. "extruding only applies shear and compression
> forces, which are unlikely to produce anisotropy".


go **** up a rope.
 
On Oct 11, 12:00 am, jim beam <[email protected]> wrote:
> [email protected] wrote:
> > On Oct 10, 3:33 pm, Peter Cole <[email protected]> wrote:
> >> article on aluminum, alloys heat treatmentshttp://www.bikepro.com/products/metals/alum.html

>
> > Golly, don't let jim beam see that!

>
> > It contains this paragraph:

>
> > "The ingots can be remelted to make cast aluminum products, using
> > various methods of casting including (in the bike industry), die
> > casting where molten aluminum is injected under high pressure into the
> > cavity of a metal die. Aluminum alloys have a reasonably low melting
> > point which makes a dense, fine-grain surface structure with excellent
> > wear and fatigue properties when die cast. Also permanent mold casting
> > may be used, which uses a metal mold repeatedly for producing many
> > castings of the same form. These casting techniques are the way many
> > crank arms, pedal bodies, hub shells, seatpost head pieces, stems, and
> > some headset parts are commercially made in volume."

>
> > When I said similar things, he switched to full, furious insult
> > mode.

>
> > - Frank Krygowski

>
> so that's why you made your mistake? does this paragraph contain the
> word "thixoforming" or "melt casting"? no? so how could it be that
> manufacturers actually use those process and not simple "die casting"
> then? [rhetorical]
>
> bottom line, that article is hugely simplified. just because
> thixoforming and extrusion are not named doesn't mean they don't exist
> or are not used.


That wasn't what you were claiming at the time, jim. Your argument
was that bike parts are not cast. When I produced enough citations
proving that many are cast, you switched to posting one word insults.

But we're talking about rims and extrusions now.

- Frank Krygowski
 
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> jim beam wrote:
>>>> Peter Cole wrote:
>>>>> jim beam wrote:
>>>>>> Peter Cole wrote:
>>>>>>> [email protected] wrote:
>>> Dear Peter,
>>>>>>>>
>>>>>>>> Can you actually stretch two spokes on a bicycle rim by
>>>>>>>> squeezing them
>>>>>>>> together?
>>>>>>>
>>>>>>> As I said above, I never have tried.
>>>>>>
>>>>>> well, well, well - the "engineer" with absolutely no interest in
>>>>>> doing anything other than opine.
>>>>>
>>>>> I don't have the equipment to do such a test. I'd need to measure
>>>>> (even to detect the largest definition of yield -- 0.2% plastic)
>>>>> half a mm over 300mm. I don't see the point, anyway.
>>>>
>>>> er, the point is that you have an opinion, and you argue the toss,
>>>> but you don't back it up with fact.
>>>
>>> No, unlike Carl, I know when I don't have the setup to do a measurement.

>>
>> maybe not from your sofa, but if you want to contribute to this
>> "debate", [as opposed to dropping sublime ignorance-bombs], get up off
>> your lardy lazy ass, go into the garage and get working with the
>> instruments.
>>
>>
>>>
>>>>>> a standard butted 1.8mm spoke gives you ~280kgf.
>>>>>
>>>>> I assume you mean something like DT "Competition" spokes. I also
>>>>> assume you're using "1.8mm" the way Jobst & DT do to indicate a
>>>>> spoke with 1.8mm ends and a 1.6mm middle.
>>>>
>>>> no, i mean 1.8mm, like 1.8mm in the butted section. just like you
>>>> yourself assumed in your earlier post.
>>>
>>> OK, as usual, adopt your own convention, but don't get testy when
>>> people misunderstand you. Isn't "1.8mm butted" redundant?

>>
>> er, there are 1.8mm straight gauge spokes. and the majority of butted
>> spokes sold are 2.0/1.8/2.0mm, so it's hardly my own "convention".
>>
>>
>>>
>>> Actually, I didn't assume that in an earlier post, that's why I got
>>> 30kg, not 40. (force = stress times *area*, remember?)

>>
>> how convenient!
>>
>>
>>>
>>>
>>>>> The standard 0.2% offset yield seems to be around 2100N from the
>>>>> curves in Jobst's book made from actual measurements on DT spokes
>>>>> of that type.
>>>>
>>>> ok...
>>>>
>>>>>
>>>>> If you mean 2.0mm butted (1.8mm middle), the 0.2% yield is still
>>>>> only around 2500N (as best I can read the curve).
>>>>
>>>> ok... oh, and how close to that yield point is a measured tension
>>>> of 175kgf?
>>>
>>> ">175" + 40 + 10 (tire) = > 225, plus a hard hand squeeze = ?? You
>>> tell me.

>>
>> i don't need to tell you - carl's done it for your lazy ass already.
>> and you have the wrong sign for tire pressure - it /reduces/ spoke
>> tension, not increases it.
>>
>>
>>>
>>>
>>>>> Where does your "1100Nmm^-2" come from? I didn't see it at the DT
>>>>> site.
>>>>
>>>> not now, but they had a different site with yield data on it not so
>>>> long ago. why don't you try the wayback machine?
>>>
>>> It's your claim, you prove it.

>>
>> no, /you/ do it because /you/ don't agree. my figures are already in
>> the archive, and are corroborated by carl fogel from the same dt
>> website i used. /you/ get your lazy ass searching the archive and
>> checking the wayback machine. mr. "extruding only applies shear and
>> compression forces, which are unlikely to produce anisotropy".

>
> go **** up a rope.


er, how can i do that when there's a giant-ass piece of peter cole
******** in the way? should i subject it to shear and compression so
it doesn't become anisotropic first?
 

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