spoke fatigue troll



A Muzi <[email protected]> wrote:
> Wow. Sorta like second marriages, multiple British cars must be
> the triumph of hope over experience. One was plenty for me.


Going for a Mini nowadays brings you BMW technology...


--
MfG/Best regards
helmut springer panta rhei
 
[email protected] wrote:
> Stress relief.
>
> I think deformation of flange holes in aluminum hubs is being
> mis-characterized, leading to incorrect assumptions about effective
> spoke hole position before and after stress relieving and that
> trueness of the wheel suffers from the process.
>
> Hole deformation is an asymptotic effect that with reasonable spoke
> tension is already as deep as it will get. If that were not so,
> spokes would gradually sink through the flange and pull out. Once
> about a third of the spoke diameter bears fully on the flange hole it
> is as deep as it will go while subsequent stress relief cannot "bed
> them in" any deeper as the process is often depicted here. The terms
> bedding in or stabilizing are a misnomers chosen by people who cannot
> visualize mechanical stress relief or that spokes bed in naturally
> from initial spoke tension.


The Rockwell hardness test (B scale, used for materials like aluminum)
uses a 1/16" (1.6mm) steel ball and measures the depth indented with
100kgf. Typical hardness numbers for aluminum would indicate a depth of
around 0.14mm (into a flat surface of reasonable thickness). While the
scenario is a bit different, the dimensions and forces are similar.
Given that the spoke and hole diameters are close and the angle is
small, it seems that the absolute "bedding in" is small and happens
early (with tension). From there it seems safe to assume that stress
relief doesn't cause any significant additional "bedding in".

Perhaps this issue is finally put to bed.
 
On 2008-05-02, Peter Cole <[email protected]> wrote:
> [email protected] wrote:
>> Stress relief.
>>
>> I think deformation of flange holes in aluminum hubs is being
>> mis-characterized, leading to incorrect assumptions about effective
>> spoke hole position before and after stress relieving and that
>> trueness of the wheel suffers from the process.
>>
>> Hole deformation is an asymptotic effect that with reasonable spoke
>> tension is already as deep as it will get. If that were not so,
>> spokes would gradually sink through the flange and pull out. Once
>> about a third of the spoke diameter bears fully on the flange hole it
>> is as deep as it will go while subsequent stress relief cannot "bed
>> them in" any deeper as the process is often depicted here. The terms
>> bedding in or stabilizing are a misnomers chosen by people who cannot
>> visualize mechanical stress relief or that spokes bed in naturally
>> from initial spoke tension.

>
> The Rockwell hardness test (B scale, used for materials like aluminum)
> uses a 1/16" (1.6mm) steel ball and measures the depth indented with
> 100kgf. Typical hardness numbers for aluminum would indicate a depth of
> around 0.14mm (into a flat surface of reasonable thickness). While the
> scenario is a bit different, the dimensions and forces are similar.
> Given that the spoke and hole diameters are close and the angle is
> small, it seems that the absolute "bedding in" is small and happens
> early (with tension). From there it seems safe to assume that stress
> relief doesn't cause any significant additional "bedding in".
>
> Perhaps this issue is finally put to bed.


I'm not quite ready to put it to bed yet.

The most likely explanation in my mind is that during stabilization the
spoke cuts into a new part of the hub flange (the outside edge of the
hole probably) that it wasn't quite bearing on before. The parts it's
already been pulled against by tensioning don't deform any further for
the reasons you state.
 
Peter Cole wrote:

>> Stress relief.


>> I think deformation of flange holes in aluminum hubs is being
>> mis-characterized, leading to incorrect assumptions about effective
>> spoke hole position before and after stress relieving and that
>> trueness of the wheel suffers from the process.


>> Hole deformation is an asymptotic effect that with reasonable spoke
>> tension is already as deep as it will get. If that were not so,
>> spokes would gradually sink through the flange and pull out. Once
>> about a third of the spoke diameter bears fully on the flange hole
>> it is as deep as it will go while subsequent stress relief cannot
>> "bed them in" any deeper as the process is often depicted here.
>> The terms bedding in or stabilizing are a misnomers chosen by
>> people who cannot visualize mechanical stress relief or that spokes
>> bed in naturally from initial spoke tension.


> The Rockwell hardness test (B scale, used for materials like
> aluminum) uses a 1/16" (1.6mm) steel ball and measures the depth
> indented with 100kgf. Typical hardness numbers for aluminum would
> indicate a depth of around 0.14mm (into a flat surface of reasonable
> thickness). While the scenario is a bit different, the dimensions
> and forces are similar. Given that the spoke and hole diameters are
> close and the angle is small, it seems that the absolute "bedding
> in" is small and happens early (with tension). From there it seems
> safe to assume that stress relief doesn't cause any significant
> additional "bedding in".


> Perhaps this issue is finally put to bed.


Don't you believe that! Not with the argumentative anti technocrats
of this forum. My distinct impression is that the situation is only
getting worse. The "In Your Face" style popular these days makes
logical and civil discourse difficult. Just the same, thanks for
researching the numbers. I arrived on this from years of observation
that led to writing about it.

Jobst Brandt
 
On Fri, 02 May 2008 10:51:00 -0500, A Muzi <[email protected]>
wrote:

>>>>> Peter Cole <[email protected]> wrote:
>>>>>> One of my cars eats head gaskets, the other one doesn't.

>
>>>> Ben C wrote:
>>>>> I share the dim view. Next time get a Japanese car :)

>
>>> Peter Cole wrote:
>>>> I've had those, and German, and Swedish, and Italian. US doesn't have a
>>>> monopoly on bad engineering, although they may have the lead.
>>>> [...]

>
>> Tom Sherman <[email protected]> wrote:
>>> Nonsense. Buy a vintage British car, and you will gain understanding.

>
>clare at snyder dot ontario dot canada wrote:
>> Yea, if it doesn't leak it doesn't contain oil. If it doesn't flicker
>> or spark it's not connected. If it isn't broken it was never
>> installed!!
>> My 1961 Mini 850 was the most dependable car I ever owned. I could
>> depend on it to make trouble just about any time - and REAL trouble at
>> the worst of times.
>>
>> Austin A65 wasn't much better - I got that one for a friend (ouch).The
>> 1972 Rover TC was a nice car- and relatively reliable(for a British
>> car) but was a REAL PIG to work on.(it was my brother's car) He also
>> had a Vauxhaul HA and a Victor Special. I had an HC (Firenza (or
>> Magnum))( Any F'renza yours ain't no f'renza mine). The Firenza was
>> actually a pretty decent car, considering I bought it for, IIRC, $250
>> when it was 4 years old!! (6 years later I got $700 for it)

>
>Wow. Sorta like second marriages, multiple British cars must be the
>triumph of hope over experience. One was plenty for me.
>
>(didn't keep me from subjecting myself to a Fiat later though)


Had one of them too. 1975 128L sport coupe. I put an aircraft
generator under the hood and 8 golf cart batteries in the trunk and it
was more reliable than the original 1.3 Liter engine.

In the Mini's defence it had 196,000 miles on it when I bought it for
$60, and 214,000 when I sold it 14 months later for $350.
** Posted from http://www.teranews.com **
 
On 2 May 2008 19:04:26 GMT, Helmut Springer <[email protected]>
wrote:

>A Muzi <[email protected]> wrote:
>> Wow. Sorta like second marriages, multiple British cars must be
>> the triumph of hope over experience. One was plenty for me.

>
>Going for a Mini nowadays brings you BMW technology...

And that's supposed to be BETTER????????????
I find they BMW in general) are about on par with Cadilac.More time in
the shop than on the road.
** Posted from http://www.teranews.com **
 
clare at snyder dot ontario dot canada wrote:
> On Wed, 30 Apr 2008 22:34:16 -0500, Tom Sherman
> <[email protected]> wrote:
>
>> Peter Cole wrote:
>>> Ben C wrote:
>>>> On 2008-04-30, Peter Cole <[email protected]> wrote:
>>> [...]
>>>>> One of my cars eats head gaskets, the other one doesn't.
>>>> I share the dim view. Next time get a Japanese car :)
>>> I've had those, and German, and Swedish, and Italian. US doesn't have a
>>> monopoly on bad engineering, although they may have the lead.
>>> [...]

>> Nonsense. Buy a vintage British car, and you will gain understanding.

>
>
> Yea, if it doesn't leak it doesn't contain oil. If it doesn't flicker
> or spark it's not connected. If it isn't broken it was never
> installed!!
> My 1961 Mini 850 was the most dependable car I ever owned. I could
> depend on it to make trouble just about any time - and REAL trouble at
> the worst of times.[...]


My worst experience was being stuck in Arkansas waiting for a
replacement fuel pump.

My MG was reliable - I could count on it to strand me on any longer trip.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful
 
On Fri, 02 May 2008 20:21:43 -0500, Tom Sherman
<[email protected]> wrote:

>clare at snyder dot ontario dot canada wrote:
>> On Wed, 30 Apr 2008 22:34:16 -0500, Tom Sherman
>> <[email protected]> wrote:
>>
>>> Peter Cole wrote:
>>>> Ben C wrote:
>>>>> On 2008-04-30, Peter Cole <[email protected]> wrote:
>>>> [...]
>>>>>> One of my cars eats head gaskets, the other one doesn't.
>>>>> I share the dim view. Next time get a Japanese car :)
>>>> I've had those, and German, and Swedish, and Italian. US doesn't have a
>>>> monopoly on bad engineering, although they may have the lead.
>>>> [...]
>>> Nonsense. Buy a vintage British car, and you will gain understanding.

>>
>>
>> Yea, if it doesn't leak it doesn't contain oil. If it doesn't flicker
>> or spark it's not connected. If it isn't broken it was never
>> installed!!
>> My 1961 Mini 850 was the most dependable car I ever owned. I could
>> depend on it to make trouble just about any time - and REAL trouble at
>> the worst of times.[...]

>
>My worst experience was being stuck in Arkansas waiting for a
>replacement fuel pump.
>
>My MG was reliable - I could count on it to strand me on any longer trip.


The ols SU electric pump required the judicious application od a small
ball pein hammer on a frequent basis to get it started (or restarted)
** Posted from http://www.teranews.com **
 
Ben C wrote:
> On 2008-05-02, Peter Cole <[email protected]> wrote:


>> The Rockwell hardness test (B scale, used for materials like aluminum)
>> uses a 1/16" (1.6mm) steel ball and measures the depth indented with
>> 100kgf. Typical hardness numbers for aluminum would indicate a depth of
>> around 0.14mm (into a flat surface of reasonable thickness). While the
>> scenario is a bit different, the dimensions and forces are similar.
>> Given that the spoke and hole diameters are close and the angle is
>> small, it seems that the absolute "bedding in" is small and happens
>> early (with tension). From there it seems safe to assume that stress
>> relief doesn't cause any significant additional "bedding in".
>>
>> Perhaps this issue is finally put to bed.

>
> I'm not quite ready to put it to bed yet.
>
> The most likely explanation in my mind is that during stabilization the
> spoke cuts into a new part of the hub flange (the outside edge of the
> hole probably) that it wasn't quite bearing on before. The parts it's
> already been pulled against by tensioning don't deform any further for
> the reasons you state.


I don't see how (when stress relieving) the spoke could make contact
with parts of the hub it hadn't already contacted with full tension.
What you seem to be suggesting is either the wall of the hole at the
flange deforming, or the face of the flange in the vicinity of the hole.
I don't see why the first wouldn't have already happened and maxed out
for the reasons above, and I don't think there's anywhere near the force
to do the second just from stress relieving. The face of the flange is
typically angled inward by about the bracing angle, and there must be a
little spoke overhang or else you couldn't lace it. Stress relieving is
only going to increase the spoke tension momentarily, nothing more, it
can't emboss the flange face with that force.

You are postulating new points of forceful contact that occur only when
stress relieving. I can't see that.
 
clare at snyder dot ontario dot canada wrote:
> On Fri, 02 May 2008 20:21:43 -0500, Tom Sherman
> <[email protected]> wrote:
>
>
>>clare at snyder dot ontario dot canada wrote:
>>
>>>On Wed, 30 Apr 2008 22:34:16 -0500, Tom Sherman
>>><[email protected]> wrote:
>>>
>>>
>>>>Peter Cole wrote:
>>>>
>>>>>Ben C wrote:
>>>>>
>>>>>>On 2008-04-30, Peter Cole <[email protected]> wrote:
>>>>>
>>>>>[...]
>>>>>
>>>>>>>One of my cars eats head gaskets, the other one doesn't.
>>>>>>
>>>>>>I share the dim view. Next time get a Japanese car :)
>>>>>
>>>>>I've had those, and German, and Swedish, and Italian. US doesn't have a
>>>>>monopoly on bad engineering, although they may have the lead.
>>>>>[...]
>>>>
>>>>Nonsense. Buy a vintage British car, and you will gain understanding.
>>>
>>>
>>>Yea, if it doesn't leak it doesn't contain oil. If it doesn't flicker
>>>or spark it's not connected. If it isn't broken it was never
>>>installed!!
>>> My 1961 Mini 850 was the most dependable car I ever owned. I could
>>>depend on it to make trouble just about any time - and REAL trouble at
>>>the worst of times.[...]

>>
>>My worst experience was being stuck in Arkansas waiting for a
>>replacement fuel pump.
>>
>>My MG was reliable - I could count on it to strand me on any longer trip.

>
>
> The ols SU electric pump required the judicious application od a small
> ball pein hammer on a frequent basis to get it started (or restarted)
> ** Posted from http://www.teranews.com **


mad props for spelling "ball pein" correctly!

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel
 
Peter Cole said:
[email protected] wrote:
> Stress relief.
>
> I think deformation of flange holes in aluminum hubs is being
> mis-characterized, leading to incorrect assumptions about effective
> spoke hole position before and after stress relieving and that
> trueness of the wheel suffers from the process.
>
> Hole deformation is an asymptotic effect that with reasonable spoke
> tension is already as deep as it will get. If that were not so,
> spokes would gradually sink through the flange and pull out. Once
> about a third of the spoke diameter bears fully on the flange hole it
> is as deep as it will go while subsequent stress relief cannot "bed
> them in" any deeper as the process is often depicted here. The terms
> bedding in or stabilizing are a misnomers chosen by people who cannot
> visualize mechanical stress relief or that spokes bed in naturally
> from initial spoke tension.


The Rockwell hardness test (B scale, used for materials like aluminum)
uses a 1/16" (1.6mm) steel ball and measures the depth indented with
100kgf. Typical hardness numbers for aluminum would indicate a depth of
around 0.14mm (into a flat surface of reasonable thickness). While the
scenario is a bit different, the dimensions and forces are similar.
Given that the spoke and hole diameters are close and the angle is
small, it seems that the absolute "bedding in" is small and happens
early (with tension). From there it seems safe to assume that stress
relief doesn't cause any significant additional "bedding in".

Perhaps this issue is finally put to bed.
Clever use of "bed" here Peter.
I don't have the explanations, but I am not against learning how to correlate observations with sound engineering explanations. One correlation you can help me with is the .75 mm you used earlier in this thread and now the .14 mm.
I understand the concept of asymptotic function and agree that there must be some point where the spokes approach it in normal operations. I would like an explanation of "what gives" when I stabilize a wheel. I build wheels to an even 100 kgf front and left rear. I then stabilize the wheel be side loading until the spokes go to 150 kgf. When I do this the front wheel needs 1/2 turn of the spokes to return to 100 kgf, while the same applies to the right rear, the left rear needs 3/4 turn. If all of the final adjustment were going to compensate for further bedding in, the further bedding would be ~.225 mm front and right rear and ~.38 mm left rear.
If I can't attribute any or all of the "final adjustment" to bedding in, where would you attribute it to?
 
Ben C wrote:
> On 2008-05-01, [email protected] <[email protected]> wrote:
>> Stress relief.
>>
>> I think deformation of flange holes in aluminum hubs is being
>> mis-characterized, leading to incorrect assumptions about effective
>> spoke hole position before and after stress relieving and that
>> trueness of the wheel suffers from the process.
>>
>> Hole deformation is an asymptotic effect that with reasonable spoke
>> tension is already as deep as it will get. If that were not so,
>> spokes would gradually sink through the flange and pull out. Once
>> about a third of the spoke diameter bears fully on the flange hole it
>> is as deep as it will go while subsequent stress relief cannot "bed
>> them in" any deeper as the process is often depicted here.

>
> I am familiar with that theory which you and Peter Cole have explained
> here before.
>
> On that basis I thought stabilization quite likely worked predominantly
> by deforming the spoke and not the hub.
>
> Jim Beam had shown pictures earlier that a spoke removed from a finished
> wheel doesn't necessarily show a big change in the elbow angle and that
> the hub hole can get significantly deformed.
>
> Here are his spokes:
> http://www.flickr.com/photos/38636024@N00/331112190/
> And this is the hub they came out of:
> http://www.flickr.com/photos/38636024@N00/104463818/
>
> But there's nothing there to suggest definitively that the hub hole
> deformation didn't happen during the initial stages of tensioning rather
> than during stabilization.


it evidences a fundamental misunderstanding [or fundamental retardation]
to claim that increasing spoke tension doesn't additionally indent a
hub's spoke holes.

brinell hardness # = P/pi.D.t

where P = indenter load, D = indenter ball diameter and t = depth of
impression.

from there, you don't have to be enrico fermi to correlate increasing
indenter load with increasing indenter depth. do you.


>
> What has re-opened this discussion are the pictures daveornee posted.
>
> http://www.flickr.com/photos/17085834@N08/2443679334/
> http://www.flickr.com/photos/17085834@N08/2443679236/
>
> In particular:
>
> http://www.flickr.com/photos/17085834@N08/2442851273/
> http://www.flickr.com/photos/17085834@N08/2443679416/
>
> Seems to show more hub hole deformation and less spoke deformation when
> compared with:
>
> http://www.flickr.com/photos/17085834@N08/2442851411/
> http://www.flickr.com/photos/17085834@N08/2442851349/
>
> This implies to me strongly that stabilization can improve spoke line by
> deforming the hub and not the spoke.
>
> Otherwise why is the hub deformed more on the side on which spoke line
> was not corrected before stabilization? During the initial stages of
> tensioning (before spoke line correction on the side that was), both
> sides of the hub were treated exactly the same. If all hub deformation
> occurs during that phase, we would expect to see the same amount of
> deformation on both sides.


nothing like the mental deformation we see from so-called "engineers"
when they doggedly try to justify their underinformed misconceptions.
 
Ben C wrote:
> On 2008-05-02, Peter Cole <[email protected]> wrote:
>> [email protected] wrote:
>>> Stress relief.
>>>
>>> I think deformation of flange holes in aluminum hubs is being
>>> mis-characterized, leading to incorrect assumptions about effective
>>> spoke hole position before and after stress relieving and that
>>> trueness of the wheel suffers from the process.
>>>
>>> Hole deformation is an asymptotic effect that with reasonable spoke
>>> tension is already as deep as it will get. If that were not so,
>>> spokes would gradually sink through the flange and pull out. Once
>>> about a third of the spoke diameter bears fully on the flange hole it
>>> is as deep as it will go while subsequent stress relief cannot "bed
>>> them in" any deeper as the process is often depicted here. The terms
>>> bedding in or stabilizing are a misnomers chosen by people who cannot
>>> visualize mechanical stress relief or that spokes bed in naturally
>>> from initial spoke tension.

>> The Rockwell hardness test (B scale, used for materials like aluminum)
>> uses a 1/16" (1.6mm) steel ball and measures the depth indented with
>> 100kgf. Typical hardness numbers for aluminum would indicate a depth of
>> around 0.14mm (into a flat surface of reasonable thickness). While the
>> scenario is a bit different, the dimensions and forces are similar.
>> Given that the spoke and hole diameters are close and the angle is
>> small, it seems that the absolute "bedding in" is small and happens
>> early (with tension). From there it seems safe to assume that stress
>> relief doesn't cause any significant additional "bedding in".
>>
>> Perhaps this issue is finally put to bed.

>
> I'm not quite ready to put it to bed yet.
>
> The most likely explanation in my mind is that during stabilization the
> spoke cuts into a new part of the hub flange (the outside edge of the
> hole probably) that it wasn't quite bearing on before. The parts it's
> already been pulled against by tensioning don't deform any further for
> the reasons you state.


this is /so/ basic. if you increase the force, you get a bigger
indentation. all you have to do is look at the formula:
http://www.key-to-steel.com/Articles/Art140.htm

it's rudimentary algebra. for a given hardness, higher force = larger
indentation. that's why standard indenter forces are used in brinell
testing.

"Unless precautions are taken to maintain P/D2 constant, which may be
experimentally inconvenient, the BHN generally will vary with load."

duh.
 
Peter Cole wrote:
> Ben C wrote:
>> On 2008-05-02, Peter Cole <[email protected]> wrote:

>
>>> The Rockwell hardness test (B scale, used for materials like
>>> aluminum) uses a 1/16" (1.6mm) steel ball and measures the depth
>>> indented with 100kgf. Typical hardness numbers for aluminum would
>>> indicate a depth of around 0.14mm (into a flat surface of reasonable
>>> thickness). While the scenario is a bit different, the dimensions and
>>> forces are similar. Given that the spoke and hole diameters are close
>>> and the angle is small, it seems that the absolute "bedding in" is
>>> small and happens early (with tension). From there it seems safe to
>>> assume that stress relief doesn't cause any significant additional
>>> "bedding in".
>>>
>>> Perhaps this issue is finally put to bed.

>>
>> I'm not quite ready to put it to bed yet.
>>
>> The most likely explanation in my mind is that during stabilization the
>> spoke cuts into a new part of the hub flange (the outside edge of the
>> hole probably) that it wasn't quite bearing on before. The parts it's
>> already been pulled against by tensioning don't deform any further for
>> the reasons you state.

>
> I don't see how (when stress relieving) the spoke could make contact
> with parts of the hub it hadn't already contacted with full tension.


it certainly makes deeper contact. increasing spoke tension deepens hub
hole indentation.


> What you seem to be suggesting is either the wall of the hole at the
> flange deforming, or the face of the flange in the vicinity of the hole.
> I don't see why the first wouldn't have already happened and maxed out
> for the reasons above, and I don't think there's anywhere near the force
> to do the second just from stress relieving. The face of the flange is
> typically angled inward by about the bracing angle, and there must be a
> little spoke overhang or else you couldn't lace it. Stress relieving is
> only going to increase the spoke tension momentarily, nothing more, it
> can't emboss the flange face with that force.
>
> You are postulating new points of forceful contact that occur only when
> stress relieving. I can't see that.



no, simply pointing out the fundamentals that you keep avoiding.
 
daveornee wrote:
> Peter Cole Wrote:
>> [email protected] wrote:
>>> Stress relief.
>>>
>>> I think deformation of flange holes in aluminum hubs is being
>>> mis-characterized, leading to incorrect assumptions about effective
>>> spoke hole position before and after stress relieving and that
>>> trueness of the wheel suffers from the process.
>>>
>>> Hole deformation is an asymptotic effect that with reasonable spoke
>>> tension is already as deep as it will get. If that were not so,
>>> spokes would gradually sink through the flange and pull out. Once
>>> about a third of the spoke diameter bears fully on the flange hole

>> it
>>> is as deep as it will go while subsequent stress relief cannot "bed
>>> them in" any deeper as the process is often depicted here. The

>> terms
>>> bedding in or stabilizing are a misnomers chosen by people who

>> cannot
>>> visualize mechanical stress relief or that spokes bed in naturally
>>> from initial spoke tension.

>> The Rockwell hardness test (B scale, used for materials like aluminum)
>> uses a 1/16" (1.6mm) steel ball and measures the depth indented with
>> 100kgf. Typical hardness numbers for aluminum would indicate a depth
>> of
>> around 0.14mm (into a flat surface of reasonable thickness). While the
>> scenario is a bit different, the dimensions and forces are similar.
>> Given that the spoke and hole diameters are close and the angle is
>> small, it seems that the absolute "bedding in" is small and happens
>> early (with tension). From there it seems safe to assume that stress
>> relief doesn't cause any significant additional "bedding in".
>>
>> Perhaps this issue is finally put to bed.

> Clever use of "bed" here Peter.
> I don't have the explanations, but I am not against learning how to
> correlate observations with sound engineering explanations. One
> correlation you can help me with is the .75 mm you used earlier in this
> thread and now the .14 mm.
> I understand the concept of asymptotic function and agree that there
> must be some point where the spokes approach it in normal operations.
> I would like an explanation of "what gives" when I stabilize a wheel. I
> build wheels to an even 100 kgf front and left rear. I then stabilize
> the wheel be side loading until the spokes go to 150 kgf. When I do
> this the front wheel needs 1/2 turn of the spokes to return to 100 kgf,
> while the same applies to the right rear, the left rear needs 3/4 turn.
> If all of the final adjustment were going to compensate for further
> bedding in, the further bedding would be ~.225 mm front and right rear
> and ~.38 mm left rear.
> If I can't attribute any or all of the "final adjustment" to bedding
> in, where would you attribute it to?
>
>


don't confront him with reality like that - you'll make him feel
uncomfortable.
 
"jim beam" wrote:
> [...]
> nothing like the mental deformation we see from so-called "engineers"


Well, they are not "so-called" if granted a PE by a licensing board.

What is your professional registration?

> when they doggedly try to justify their underinformed misconceptions.


No hint of resentment here, eh?

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful
 
"jim beam" wrote:
> Ben C wrote:
>> On 2008-05-02, Peter Cole <[email protected]> wrote:
>>> [email protected] wrote:
>>>> Stress relief.
>>>>
>>>> I think deformation of flange holes in aluminum hubs is being
>>>> mis-characterized, leading to incorrect assumptions about effective
>>>> spoke hole position before and after stress relieving and that
>>>> trueness of the wheel suffers from the process.
>>>>
>>>> Hole deformation is an asymptotic effect that with reasonable spoke
>>>> tension is already as deep as it will get. If that were not so,
>>>> spokes would gradually sink through the flange and pull out. Once
>>>> about a third of the spoke diameter bears fully on the flange hole it
>>>> is as deep as it will go while subsequent stress relief cannot "bed
>>>> them in" any deeper as the process is often depicted here. The terms
>>>> bedding in or stabilizing are a misnomers chosen by people who cannot
>>>> visualize mechanical stress relief or that spokes bed in naturally
>>>> from initial spoke tension.
>>> The Rockwell hardness test (B scale, used for materials like
>>> aluminum) uses a 1/16" (1.6mm) steel ball and measures the depth
>>> indented with 100kgf. Typical hardness numbers for aluminum would
>>> indicate a depth of around 0.14mm (into a flat surface of reasonable
>>> thickness). While the scenario is a bit different, the dimensions and
>>> forces are similar. Given that the spoke and hole diameters are close
>>> and the angle is small, it seems that the absolute "bedding in" is
>>> small and happens early (with tension). From there it seems safe to
>>> assume that stress relief doesn't cause any significant additional
>>> "bedding in".
>>>
>>> Perhaps this issue is finally put to bed.

>>
>> I'm not quite ready to put it to bed yet.
>>
>> The most likely explanation in my mind is that during stabilization the
>> spoke cuts into a new part of the hub flange (the outside edge of the
>> hole probably) that it wasn't quite bearing on before. The parts it's
>> already been pulled against by tensioning don't deform any further for
>> the reasons you state.

>
> this is /so/ basic. if you increase the force, you get a bigger
> indentation. all you have to do is look at the formula:
> http://www.key-to-steel.com/Articles/Art140.htm [...]
>

Does not the area deformed during initial tensioning work harden, and
would that not reduce the deformation from spoke squeezing?

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful
 
[email protected] wrote:
> On 02 May 2008 00:04:51 GMT, [email protected] wrote:
>
>> Carl Fogel wrote:
>>
>>>> Beyond that, today it is all about materials that, although claimed
>>>> to be superior, perform more poorly.
>>> The last I heard, something changed between the 1st and 3rd editions
>>> of "The Bicycle Wheel" and significantly altered the durability of
>>> spokes:

>> You're trying too hard. The new materials are Kevlar and Carbon fiber
>> along with hard anodized rims and hubs. Because the spokes of old
>> required careful spoke alignment and stress relief, Today some spokes
>> survive in spite of less skilled attention, but that could also be
>> that the wheels don't get as much use as the ones of yore.
>>
>>> "It appears that the better spokes now available would have made the
>>> discovery of many of the concepts of this book more difficult for
>>> lack of failure data. I am grateful in retrospect for the poor
>>> durability of earlier spokes. They operated so near their limits
>>> that durability was significantly altered by the techniques that I
>>> have outlined."

>> That has more to do with assessing how effective stress relief is than
>> with how long spokes last before failure. As I have often mentioned,
>> spokes in my old wheels from the 1970's on which I developed the
>> methods, have more than 300,000 miles service at 10,000 miles per year
>> or more.
>>
>>> --Jobst Brandt, "The Bicycle Wheel," 3rd Edition, 1993, p.124

>> I'm glad you have a copy of the book. It still sells well today.
>>
>> Jobst Brandt

>
> Dear Jobst,
>
> I sense that you're not trying hard enough.
>
> Someone or other tested spokes in 1981 and again 1988. He published
> stress-strain graphs, showing the results.
>
> In 1981, he tested carbon steel and stainless steel spokes. They all
> pulled apart, failing after stretching less than 0.15" (3.8 mm).
>
> By 1988, only seven years later, he didn't bother testing carbon steel
> spokes because most riders had stopped using the old material by 1988
> and embraced the new stainless steel material for some reason or
> other.
>
> Interestingly, some stainless steel spokes from the same company (DT)
> stretched so far in 1988 that the tester gave up trying to make them
> fail in his second test. The stress-strain graph just goes level.
>
> The 1981 stainless steel spokes all failed below 4 mm of stretch. The
> 1988 spokes stretch 25% to 50% more, failing at 5 mm to 6 mm, or even
> showing no sign of failure.
>
> It's as if the spoke material changed significantly.
>
> That might explain the tester's comment five years later in 1993 that
> spokes had become significantly more durable.
>
> He never shared whatever "data" he had in mind about durability, but
> his claim for an impressive improvement in spoke durability is
> supported by the fact that the practice of carrying spare spokes
> practically vanished around that time.
>
> Cheers,
>
> Carl Fogel



illuminating.
 
Tom Sherman wrote:
> "jim beam" wrote:
>> [...]
>> nothing like the mental deformation we see from so-called "engineers"

>
> Well, they are not "so-called" if granted a PE by a licensing board.
>
> What is your professional registration?
>
>> when they doggedly try to justify their underinformed misconceptions.

>
> No hint of resentment here, eh?
>


refusing to address the "engineering" then tom? shouldn't be too hard
for a "professional" to do. unless they're a lightweight of course.
 
Tom Sherman wrote:
> "jim beam" wrote:
>> Ben C wrote:
>>> On 2008-05-02, Peter Cole <[email protected]> wrote:
>>>> [email protected] wrote:
>>>>> Stress relief.
>>>>>
>>>>> I think deformation of flange holes in aluminum hubs is being
>>>>> mis-characterized, leading to incorrect assumptions about effective
>>>>> spoke hole position before and after stress relieving and that
>>>>> trueness of the wheel suffers from the process.
>>>>>
>>>>> Hole deformation is an asymptotic effect that with reasonable spoke
>>>>> tension is already as deep as it will get. If that were not so,
>>>>> spokes would gradually sink through the flange and pull out. Once
>>>>> about a third of the spoke diameter bears fully on the flange hole it
>>>>> is as deep as it will go while subsequent stress relief cannot "bed
>>>>> them in" any deeper as the process is often depicted here. The terms
>>>>> bedding in or stabilizing are a misnomers chosen by people who cannot
>>>>> visualize mechanical stress relief or that spokes bed in naturally
>>>>> from initial spoke tension.
>>>> The Rockwell hardness test (B scale, used for materials like
>>>> aluminum) uses a 1/16" (1.6mm) steel ball and measures the depth
>>>> indented with 100kgf. Typical hardness numbers for aluminum would
>>>> indicate a depth of around 0.14mm (into a flat surface of reasonable
>>>> thickness). While the scenario is a bit different, the dimensions
>>>> and forces are similar. Given that the spoke and hole diameters are
>>>> close and the angle is small, it seems that the absolute "bedding
>>>> in" is small and happens early (with tension). From there it seems
>>>> safe to assume that stress relief doesn't cause any significant
>>>> additional "bedding in".
>>>>
>>>> Perhaps this issue is finally put to bed.
>>>
>>> I'm not quite ready to put it to bed yet.
>>>
>>> The most likely explanation in my mind is that during stabilization the
>>> spoke cuts into a new part of the hub flange (the outside edge of the
>>> hole probably) that it wasn't quite bearing on before. The parts it's
>>> already been pulled against by tensioning don't deform any further for
>>> the reasons you state.

>>
>> this is /so/ basic. if you increase the force, you get a bigger
>> indentation. all you have to do is look at the formula:
>> http://www.key-to-steel.com/Articles/Art140.htm [...]
>>

> Does not the area deformed during initial tensioning work harden, and
> would that not reduce the deformation from spoke squeezing?
>


why do you think hardness numbers are comparatively, not quantitatively
correlated with strength?

lightweight.