Headset dead spot?

[[email protected]]

On Apr 2, 11:14 pm, jim beam <[email protected]> wrote:
> [email protected] wrote:
> > Craig Williams wrote:
>
> >> [Note: Normally I would search the archives to find previous
> >> messages, but the Google Advanced Groups Search no longer works. Is
> >> there another tool for that?]
>
> >> It seems that my front wheel steering has a "dead spot" such that
> >> the front wheel wants to point straight ahead (like there is a
> >> detent). Is a headset adjustment called for?
>
> >> This is a Chris King threaded headset on a road bike.
>
> >http://www.sheldonbrown.com/brandt/indexed-steering.html
>
> > I think Google can find that one. Anyway, you might add that to your
> > favorites.
>
> not only is the premise of that article incorrect, it contains other
> significant inaccuracies. rotating bearings /do/ indeed have metallic
> contact up until the point of hydrodynamic separation.
>
> http://www.tribology-abc.com/calculators/e12_3.htm
>
> separation only occurs at significant speed. at higher loads, it may
> never occur. for you to contend that headset bearings are somehow
> different from all the other bearings on a bike for which hydrodynamic
> separation also does /not/ occur, is both ignorant and misleading.
>
> furthermore, another poster to this group actually bothered to do
> hardness testing of some headset bearings and found that low hardness
> bearing races indexed quickly, while those with harder races didn't.
> this is entirely in accordance with indexing being the product of
> overload, [true brinelling] not "fretting" [false brinelling].

Only if you choose to look at it that way. A softer race will index
more easily than a harder on under Jobst's theory as well. Have you
observed raised areas around the dimples in your races that would
prove overload, or are you just guessing?

 

[[email protected]]

On Apr 3, 4:28 am, Ben C <[email protected]> wrote:
> On 2008-04-03, jim beam <[email protected]> wrote:
>
>
>
> > Williams wrote:
> >> [Note: Normally I would search the archives to find previous messages, but
> >> the Google Advanced Groups Search no longer works. Is there another tool
> >> for that?]
>
> >> It seems that my front wheel steering has a "dead spot" such that the front
> >> wheel wants to point straight ahead (like there is a detent). Is a headset
> >> adjustment called for?
>
> >> This is a Chris King threaded headset on a road bike.
>
> >> thanks,
> >> Craig
>
> > probably the product of over-zealous fitting by the installer and
> > subsequent brinelling damage. c.k. headsets require a custom attachment
> > for the bearing press, and not everyone bothers to use one.
>
> Do you mean they got brinelled as they were hammered into the frame?
>
> That's one I've not heard. I thought in the usual "true brinelling"
> version of events, the brinelling happens when you ride over a nasty
> bump with the front wheel?

No. He's implying that care may not have been taken to install the
headset with the races parallel - I'm inclined to believe that - and
thus the compressive load was concentrated on one ball. "True
brinelling" (This, Ricod, is why professionals define their terms and
don't let the definition migrate. We don't like using air quotes to
kludge together an effective meaning.) may seem likely when hitting a
bump, but the loads are rarely high enough. An impact that would
actually indent the races on a properly installed King headset would
shatter the riders wrists.

 

[jim beam]

[email protected] wrote:
> On Apr 2, 11:14 pm, jim beam <[email protected]> wrote:
>> [email protected] wrote:
>>> Craig Williams wrote:
>>>> [Note: Normally I would search the archives to find previous
>>>> messages, but the Google Advanced Groups Search no longer works. Is
>>>> there another tool for that?]
>>>> It seems that my front wheel steering has a "dead spot" such that
>>>> the front wheel wants to point straight ahead (like there is a
>>>> detent). Is a headset adjustment called for?
>>>> This is a Chris King threaded headset on a road bike.
>>> http://www.sheldonbrown.com/brandt/indexed-steering.html
>>> I think Google can find that one. Anyway, you might add that to your
>>> favorites.
>> not only is the premise of that article incorrect, it contains other
>> significant inaccuracies. rotating bearings /do/ indeed have metallic
>> contact up until the point of hydrodynamic separation.
>>
>> http://www.tribology-abc.com/calculators/e12_3.htm
>>
>> separation only occurs at significant speed. at higher loads, it may
>> never occur. for you to contend that headset bearings are somehow
>> different from all the other bearings on a bike for which hydrodynamic
>> separation also does /not/ occur, is both ignorant and misleading.
>>
>> furthermore, another poster to this group actually bothered to do
>> hardness testing of some headset bearings and found that low hardness
>> bearing races indexed quickly, while those with harder races didn't.
>> this is entirely in accordance with indexing being the product of
>> overload, [true brinelling] not "fretting" [false brinelling].
>
> Only if you choose to look at it that way. A softer race will index
> more easily than a harder on under Jobst's theory as well.

not true. false brinelling is largely chemical, not physical - bearings
don't false-brinell in oxygen-free environments.


> Have you
> observed raised areas around the dimples in your races that would
> prove overload, or are you just guessing?

how large do /you/ expect raised areas to be in a hardened steel?
especially one where the race substrate is the same magnitude of depth
as the indentation itself?

 

[jim beam]

Ben C wrote:
> On 2008-04-03, jim beam <[email protected]> wrote:
>> Williams wrote:
>>> [Note: Normally I would search the archives to find previous messages, but
>>> the Google Advanced Groups Search no longer works. Is there another tool
>>> for that?]
>>>
>>> It seems that my front wheel steering has a "dead spot" such that the front
>>> wheel wants to point straight ahead (like there is a detent). Is a headset
>>> adjustment called for?
>>>
>>> This is a Chris King threaded headset on a road bike.
>>>
>>> thanks,
>>> Craig
>>>
>>>
>> probably the product of over-zealous fitting by the installer and
>> subsequent brinelling damage. c.k. headsets require a custom attachment
>> for the bearing press, and not everyone bothers to use one.
>
> Do you mean they got brinelled as they were hammered into the frame?

hammered or pressed. over-load is over-load, the bearings care not how
it occurs.


>
> That's one I've not heard. I thought in the usual "true brinelling"
> version of events, the brinelling happens when you ride over a nasty
> bump with the front wheel?

crashing will do it too.

 

[jim beam]

[email protected] wrote:<snip for clarity>

> An impact that would
> actually indent the races on a properly installed King headset would
> shatter the riders wrists.

that's simply presumption. [and presumption is not fact.]

fact: i've true-brinelled a headset in a crash - i rear-ended a car.
instant brinelling. no bones broken. no other damage to the bike.

 

[RicodJour]

On Apr 3, 7:21 am, [email protected] wrote:
>
> This, Ricod, is why professionals define their terms and
> don't let the definition migrate. We don't like using air quotes to
> kludge together an effective meaning.

The term has already migrated. Professionals use the migrated term
all of the time. Brinell is a test, so unless you test your bike by
purposefully overloading your bearings under controlled conditions,
then brinelling refers to the similarity in appearance of the
resulting damage. The modifiers true and false seem to cover the
bases pretty well.

Maintaining linguistic purity is admirable when it's attempting to
clarify communication, but once the word has gained or lost a certain
meaning, it's as ridiculous as 'correcting' someone saying Band-Aid
(or bandaid) by commenting, "You mean 'adhesive bandage'."

R

 

[landotter]

On Apr 2, 4:59 pm, "Williams" <[email protected]> wrote:
> [Note:  Normally I would search the archives to find previous messages, but
> the Google Advanced Groups Search no longer works.  Is there another tool
> for that?]
>
> It seems that my front wheel steering has a "dead spot" such that the front
> wheel wants to point straight ahead (like there is a detent).  Is a headset
> adjustment called for?
>
> This is a Chris King threaded headset on a road bike.
>
Shimano STX headset: $20
One hour, two beers. Replace as needed. Price means that it'll blow
you away--after six months you'll go, "This $20 headset has been
smooth for 6 freaking' months, WooHoo!!!" instead of moaning about
warrantying some overpriced bit of bling.

 

[[email protected]]

On Apr 3, 9:00 am, jim beam <[email protected]> wrote:
> [email protected] wrote:
> >
>
> > Only if you choose to look at it that way. A softer race will index
> > more easily than a harder on under Jobst's theory as well.
>
> not true. false brinelling is largely chemical, not physical - bearings
> don't false-brinell in oxygen-free environments.

You're trying to get an awful lot of mileage out of the word
"largely." IOW, you get false brinelling with vibration. You don't
get false brinelling without vibration, even though oxygen is
present. And there's no practical way to keep oxygen out of your
headset. So which is more important?

Until we start inflating our headsets with the same miracle nitrogen
some folks use in tires, I'd say the physical vibration is the more
important factor.

> > Have you
> > observed raised areas around the dimples in your races that would
> > prove overload, or are you just guessing?
>
> how large do /you/ expect raised areas to be in a hardened steel?
> especially one where the race substrate is the same magnitude of depth
> as the indentation itself?

I take it the brief version of your answer is "No."

- Frank Krygowski

 

[[email protected]]

On Apr 3, 10:18 am, RicodJour <[email protected]> wrote:
> On Apr 3, 7:21 am, [email protected] wrote:
>
>
>
> > This, Ricod, is why professionals define their terms and
> > don't let the definition migrate. We don't like using air quotes to
> > kludge together an effective meaning.
>
> The term has already migrated. Professionals use the migrated term
> all of the time. Brinell is a test, so unless you test your bike by
> purposefully overloading your bearings under controlled conditions,
> then brinelling refers to the similarity in appearance of the
> resulting damage. The modifiers true and false seem to cover the
> bases pretty well.
>
> Maintaining linguistic purity is admirable when it's attempting to
> clarify communication, but once the word has gained or lost a certain
> meaning, it's as ridiculous as 'correcting' someone saying Band-Aid
> (or bandaid) by commenting, "You mean 'adhesive bandage'."
>
> R

The correction would not be ridiculous if you start using Band-Aid to
refer to electrical tape and "true Band-Aid" to refer to a bandage.

 

[[email protected]]

On Apr 3, 9:00 am, jim beam <[email protected]> wrote:
> [email protected] wrote:
> > On Apr 2, 11:14 pm, jim beam <[email protected]> wrote:
> >> [email protected] wrote:
> >>> Craig Williams wrote:
> >>>> [Note: Normally I would search the archives to find previous
> >>>> messages, but the Google Advanced Groups Search no longer works. Is
> >>>> there another tool for that?]
> >>>> It seems that my front wheel steering has a "dead spot" such that
> >>>> the front wheel wants to point straight ahead (like there is a
> >>>> detent). Is a headset adjustment called for?
> >>>> This is a Chris King threaded headset on a road bike.
> >>>http://www.sheldonbrown.com/brandt/indexed-steering.html
> >>> I think Google can find that one. Anyway, you might add that to your
> >>> favorites.
> >> not only is the premise of that article incorrect, it contains other
> >> significant inaccuracies. rotating bearings /do/ indeed have metallic
> >> contact up until the point of hydrodynamic separation.
>
> >>http://www.tribology-abc.com/calculators/e12_3.htm
>
> >> separation only occurs at significant speed. at higher loads, it may
> >> never occur. for you to contend that headset bearings are somehow
> >> different from all the other bearings on a bike for which hydrodynamic
> >> separation also does /not/ occur, is both ignorant and misleading.
>
> >> furthermore, another poster to this group actually bothered to do
> >> hardness testing of some headset bearings and found that low hardness
> >> bearing races indexed quickly, while those with harder races didn't.
> >> this is entirely in accordance with indexing being the product of
> >> overload, [true brinelling] not "fretting" [false brinelling].
>
> > Only if you choose to look at it that way. A softer race will index
> > more easily than a harder on under Jobst's theory as well.
>
> not true. false brinelling is largely chemical, not physical - bearings
> don't false-brinell in oxygen-free environments.
>
> > Have you
> > observed raised areas around the dimples in your races that would
> > prove overload, or are you just guessing?
>
> how large do /you/ expect raised areas to be in a hardened steel?
> especially one where the race substrate is the same magnitude of depth
> as the indentation itself?

When a ball leaves an indentation in a piece of metal, the displaced
material needs to go somewhere. Now that material was either lost to
errosion (Jobst's theory), or it resulted in distortion of the
surrounding material (the result of your theory, whether or not you
choose to believe it). It's a simple question. Have you or have you
not made the observations to meet the sufficient conditions of what
you're telling us?

 

[John Thompson]

On 2008-04-02, Williams <[email protected]> wrote:

> It seems that my front wheel steering has a "dead spot" such that the front
> wheel wants to point straight ahead (like there is a detent). Is a headset
> adjustment called for?

"Indexed steering?"

The bottom race is probably damaged. A quick 'n' dirty fix is to replace
caged bearings with loose balls, adding one more ball so the balls don't
fall into the fretted craters so readily.

Another one is to pop off the crown race, rotate it a little, and
reinstall it, putting the craters in a different orientation.

Neither one of these is likely to provide long-term satisfaction; the
real fix is to replace the damaged parts with new ones.

--

John ([email protected])

 

[jim beam]

[email protected] wrote:
> On Apr 3, 9:00 am, jim beam <[email protected]> wrote:
>> [email protected] wrote:
>>> On Apr 2, 11:14 pm, jim beam <[email protected]> wrote:
>>>> [email protected] wrote:
>>>>> Craig Williams wrote:
>>>>>> [Note: Normally I would search the archives to find previous
>>>>>> messages, but the Google Advanced Groups Search no longer works. Is
>>>>>> there another tool for that?]
>>>>>> It seems that my front wheel steering has a "dead spot" such that
>>>>>> the front wheel wants to point straight ahead (like there is a
>>>>>> detent). Is a headset adjustment called for?
>>>>>> This is a Chris King threaded headset on a road bike.
>>>>> http://www.sheldonbrown.com/brandt/indexed-steering.html
>>>>> I think Google can find that one. Anyway, you might add that to your
>>>>> favorites.
>>>> not only is the premise of that article incorrect, it contains other
>>>> significant inaccuracies. rotating bearings /do/ indeed have metallic
>>>> contact up until the point of hydrodynamic separation.
>>>> http://www.tribology-abc.com/calculators/e12_3.htm
>>>> separation only occurs at significant speed. at higher loads, it may
>>>> never occur. for you to contend that headset bearings are somehow
>>>> different from all the other bearings on a bike for which hydrodynamic
>>>> separation also does /not/ occur, is both ignorant and misleading.
>>>> furthermore, another poster to this group actually bothered to do
>>>> hardness testing of some headset bearings and found that low hardness
>>>> bearing races indexed quickly, while those with harder races didn't.
>>>> this is entirely in accordance with indexing being the product of
>>>> overload, [true brinelling] not "fretting" [false brinelling].
>>> Only if you choose to look at it that way. A softer race will index
>>> more easily than a harder on under Jobst's theory as well.
>> not true. false brinelling is largely chemical, not physical - bearings
>> don't false-brinell in oxygen-free environments.
>>
>>> Have you
>>> observed raised areas around the dimples in your races that would
>>> prove overload, or are you just guessing?
>> how large do /you/ expect raised areas to be in a hardened steel?
>> especially one where the race substrate is the same magnitude of depth
>> as the indentation itself?
>
> When a ball leaves an indentation in a piece of metal, the displaced
> material needs to go somewhere.

indeed. that's why i carefully raised the point about the thickness of
the race.


> Now that material was either lost to
> errosion (Jobst's theory), or it resulted in distortion of the
> surrounding material (the result of your theory, whether or not you
> choose to believe it).

er, see above.


> It's a simple question. Have you or have you
> not made the observations to meet the sufficient conditions of what
> you're telling us?

actually, i have.

 

[jim beam]

[email protected] wrote:
> On Apr 3, 9:00 am, jim beam <[email protected]> wrote:
>> [email protected] wrote:
>>> Only if you choose to look at it that way. A softer race will index
>>> more easily than a harder on under Jobst's theory as well.
>> not true. false brinelling is largely chemical, not physical - bearings
>> don't false-brinell in oxygen-free environments.
>
> You're trying to get an awful lot of mileage out of the word
> "largely." IOW, you get false brinelling with vibration. You don't
> get false brinelling without vibration,

you know krygowski, for someone that masquerades as an engineering
professor, you look remarkably like a complete blathering idiot.

false brinelling is not simply a function of vibration, it's a function
of chemistry and load as well. loose bearings false brinell, pre-loaded
ones don't. bearings without oxygen don't false brinell. and to a
lesser extent, those benefiting from certain lubricants such as those
containing calcium sulfonate, either don't or only do so to a much
smaller degree.

conclusion: correct pre-load and correct lubricant is the practical
solution.


> even though oxygen is
> present. And there's no practical way to keep oxygen out of your
> headset. So which is more important?
>
> Until we start inflating our headsets with the same miracle nitrogen
> some folks use in tires, I'd say the physical vibration is the more
> important factor.

"you'd say" means you don't know your facts, you're simply guessing. idiot.


>
>>> Have you
>>> observed raised areas around the dimples in your races that would
>>> prove overload, or are you just guessing?
>> how large do /you/ expect raised areas to be in a hardened steel?
>> especially one where the race substrate is the same magnitude of depth
>> as the indentation itself?
>
> I take it the brief version of your answer is "No."

see above. idiot.

 

[[email protected]]

On Apr 3, 11:25 pm, jim beam <[email protected]> wrote:
> [email protected] wrote:
> > On Apr 3, 9:00 am, jim beam <[email protected]> wrote:
> >> false brinelling is largely chemical, not physical - bearings
> >> don't false-brinell in oxygen-free environments.
>
> > You're trying to get an awful lot of mileage out of the word
> > "largely." IOW, you get false brinelling with vibration. You don't
> > get false brinelling without vibration,
>
> false brinelling is not simply a function of vibration, it's a function
> of chemistry and load as well.

<sigh> A careful reader will note that I did not say false brinelling
is _only_ a function of vibration.

However, to simplify your "chemistry" argument a bit: The chemistry
is dependent on oxygen. If we wish to prevent false brinelling, we
can mitigate the effects of vibration, or we can remove all oxygen
from the neighborhood of the bearing. Which is more practical?

> loose bearings false brinell, pre-loaded ones don't.

Wrong.

- Frank Krygowski

 

[[email protected]]

On Apr 3, 11:24 pm, jim beam <[email protected]> wrote:
> [email protected] wrote:
> > On Apr 3, 9:00 am, jim beam <[email protected]> wrote:
> >> [email protected] wrote:
> >>> On Apr 2, 11:14 pm, jim beam <[email protected]> wrote:
> >>>> [email protected] wrote:
> >>>>> Craig Williams wrote:
> >>>>>> [Note: Normally I would search the archives to find previous
> >>>>>> messages, but the Google Advanced Groups Search no longer works. Is
> >>>>>> there another tool for that?]
> >>>>>> It seems that my front wheel steering has a "dead spot" such that
> >>>>>> the front wheel wants to point straight ahead (like there is a
> >>>>>> detent). Is a headset adjustment called for?
> >>>>>> This is a Chris King threaded headset on a road bike.
> >>>>>http://www.sheldonbrown.com/brandt/indexed-steering.html
> >>>>> I think Google can find that one. Anyway, you might add that to your
> >>>>> favorites.
> >>>> not only is the premise of that article incorrect, it contains other
> >>>> significant inaccuracies. rotating bearings /do/ indeed have metallic
> >>>> contact up until the point of hydrodynamic separation.
> >>>>http://www.tribology-abc.com/calculators/e12_3.htm
> >>>> separation only occurs at significant speed. at higher loads, it may
> >>>> never occur. for you to contend that headset bearings are somehow
> >>>> different from all the other bearings on a bike for which hydrodynamic
> >>>> separation also does /not/ occur, is both ignorant and misleading.
> >>>> furthermore, another poster to this group actually bothered to do
> >>>> hardness testing of some headset bearings and found that low hardness
> >>>> bearing races indexed quickly, while those with harder races didn't.
> >>>> this is entirely in accordance with indexing being the product of
> >>>> overload, [true brinelling] not "fretting" [false brinelling].
> >>> Only if you choose to look at it that way. A softer race will index
> >>> more easily than a harder on under Jobst's theory as well.
> >> not true. false brinelling is largely chemical, not physical - bearings
> >> don't false-brinell in oxygen-free environments.
>
> >>> Have you
> >>> observed raised areas around the dimples in your races that would
> >>> prove overload, or are you just guessing?
> >> how large do /you/ expect raised areas to be in a hardened steel?
> >> especially one where the race substrate is the same magnitude of depth
> >> as the indentation itself?
>
> > When a ball leaves an indentation in a piece of metal, the displaced
> > material needs to go somewhere.
>
> indeed. that's why i carefully raised the point about the thickness of
> the race.
>

I'm not following. Does an incompressible solid become compressible
under your carefully raised set of circumstances? The full volume of
metal is either there or it's not. The thickness of the race does not
change this fact.


> > Now that material was either lost to
> > errosion (Jobst's theory), or it resulted in distortion of the
> > surrounding material (the result of your theory, whether or not you
> > choose to believe it).
>
> er, see above.
>
> > It's a simple question. Have you or have you
> > not made the observations to meet the sufficient conditions of what
> > you're telling us?
>
> actually, i have.

Where? So far you've alternately suggested that the disruption to the
surrounding free surfaces was too small to measure and carefully
raised the point that there is no disruption because of the race
thickness. Neither of these claims is true in any universe where mass
is conserved. If you want to present this to us as a case of purely
plastic deformation, you're going to have to show us where the
displaced metal went.

 

[jim beam]

[email protected] wrote:
> On Apr 3, 11:25 pm, jim beam <[email protected]> wrote:
>> [email protected] wrote:
>>> On Apr 3, 9:00 am, jim beam <[email protected]> wrote:
>>>> false brinelling is largely chemical, not physical - bearings
>>>> don't false-brinell in oxygen-free environments.
>>> You're trying to get an awful lot of mileage out of the word
>>> "largely." IOW, you get false brinelling with vibration. You don't
>>> get false brinelling without vibration,
>> false brinelling is not simply a function of vibration, it's a function
>> of chemistry and load as well.
>
> <sigh> A careful reader will note that I did not say false brinelling
> is _only_ a function of vibration.
>
> However, to simplify your "chemistry" argument a bit: The chemistry
> is dependent on oxygen. If we wish to prevent false brinelling, we
> can mitigate the effects of vibration, or we can remove all oxygen
> from the neighborhood of the bearing. Which is more practical?

you snip the "practical" solution i gave you, then you try to imply that
there isn't one??? you're a freakin' idiot krygowski.


>
>> loose bearings false brinell, pre-loaded ones don't.
>
> Wrong.
>

actually, i'm not. look it up. and you're still a freakin' idiot.

 

[jim beam]

[email protected] wrote:
> On Apr 3, 11:24 pm, jim beam <[email protected]> wrote:
>> [email protected] wrote:
>>> On Apr 3, 9:00 am, jim beam <[email protected]> wrote:
>>>> [email protected] wrote:
>>>>> On Apr 2, 11:14 pm, jim beam <[email protected]> wrote:
>>>>>> [email protected] wrote:
>>>>>>> Craig Williams wrote:
>>>>>>>> [Note: Normally I would search the archives to find previous
>>>>>>>> messages, but the Google Advanced Groups Search no longer works. Is
>>>>>>>> there another tool for that?]
>>>>>>>> It seems that my front wheel steering has a "dead spot" such that
>>>>>>>> the front wheel wants to point straight ahead (like there is a
>>>>>>>> detent). Is a headset adjustment called for?
>>>>>>>> This is a Chris King threaded headset on a road bike.
>>>>>>> http://www.sheldonbrown.com/brandt/indexed-steering.html
>>>>>>> I think Google can find that one. Anyway, you might add that to your
>>>>>>> favorites.
>>>>>> not only is the premise of that article incorrect, it contains other
>>>>>> significant inaccuracies. rotating bearings /do/ indeed have metallic
>>>>>> contact up until the point of hydrodynamic separation.
>>>>>> http://www.tribology-abc.com/calculators/e12_3.htm
>>>>>> separation only occurs at significant speed. at higher loads, it may
>>>>>> never occur. for you to contend that headset bearings are somehow
>>>>>> different from all the other bearings on a bike for which hydrodynamic
>>>>>> separation also does /not/ occur, is both ignorant and misleading.
>>>>>> furthermore, another poster to this group actually bothered to do
>>>>>> hardness testing of some headset bearings and found that low hardness
>>>>>> bearing races indexed quickly, while those with harder races didn't.
>>>>>> this is entirely in accordance with indexing being the product of
>>>>>> overload, [true brinelling] not "fretting" [false brinelling].
>>>>> Only if you choose to look at it that way. A softer race will index
>>>>> more easily than a harder on under Jobst's theory as well.
>>>> not true. false brinelling is largely chemical, not physical - bearings
>>>> don't false-brinell in oxygen-free environments.
>>>>> Have you
>>>>> observed raised areas around the dimples in your races that would
>>>>> prove overload, or are you just guessing?
>>>> how large do /you/ expect raised areas to be in a hardened steel?
>>>> especially one where the race substrate is the same magnitude of depth
>>>> as the indentation itself?
>>> When a ball leaves an indentation in a piece of metal, the displaced
>>> material needs to go somewhere.
>> indeed. that's why i carefully raised the point about the thickness of
>> the race.
>>
>
> I'm not following.

i think you are. i also think you're [somewhat clumsily] trying to confuse.


> Does an incompressible solid become compressible
> under your carefully raised set of circumstances?

of course not.


> The full volume of
> metal is either there or it's not. The thickness of the race does not
> change this fact.

why did i raise the point about the thickness of the race? decoy?
********? or is it anything to do with the fact that you only get
positive displacement when the material under the ball is sufficiently
massive that the only way for plastic displacement to go is "up? if the
material is thin, like in a bike head set, the material can go pretty
much any way it wants, including "down".


>
>
>>> Now that material was either lost to
>>> errosion (Jobst's theory), or it resulted in distortion of the
>>> surrounding material (the result of your theory, whether or not you
>>> choose to believe it).
>> er, see above.
>>
>>> It's a simple question. Have you or have you
>>> not made the observations to meet the sufficient conditions of what
>>> you're telling us?
>> actually, i have.
>
> Where? So far you've alternately suggested that the disruption to the
> surrounding free surfaces was too small to measure and carefully
> raised the point that there is no disruption because of the race
> thickness. Neither of these claims is true in any universe where mass
> is conserved. If you want to present this to us as a case of purely
> plastic deformation, you're going to have to show us where the
> displaced metal went.
>

you either have no experience of this stuff or you're being a
bullshitter. true brinell testing requires significant material
thickness. look it up. and the reason is precisely that which you're
trying so hard to avoid.

 

[[email protected]]

Craig Williams wrote:

>>>> [Note: Normally I would search the archives to find previous
>>>> messages, but the Google Advanced Groups Search no longer works.
>>>> Is there another tool for that?] It seems that my front wheel
>>>> steering has a "dead spot" such that the front wheel wants to
>>>> point straight ahead (like there is a detent). Is a headset
>>>> adjustment called for? This is a Chris King threaded headset on
>>>> a road bike.

http://www.sheldonbrown.com/brandt/indexed-steering.html

>>> I think Google can find that one. Anyway, you might add that to
>>> your favorites.

>> Why did you object to the word Brinell in that article? The term
>> itself is not at fault, nor was the - not surprisingly uncredited -
>> OP in describing the problem. That is what indexed headsets refer
>> to - the only question is whether it is Brinelling due to excessive
>> load or ambient conditions.

>> To the OP: is there a single dead spot, or do you find other
>> 'resting spots' as you rotate the handlebars?

> I appreciate the quick replies. There is only one dead spot at dead
> center.

If you consider what bearing balls do when cup and cone rotate, you
will see that bearing balls in a linear (roll case) move half the
distance the races move with respect to each other. For a circular
bearing the ratio is not as easily defined because the races travel in
a circular path so that the motion ratio is an odd function involving
the value pi.

Hence a rematch of balls to dimples when the inner race is rotated to
again be opposite the initial straight ahead dimple pattern, bearing
balls will not arrive at that location. However, moving the ball
complement a half space from the dimple position will not help because
they will move gradually to get back to that position.

Offsetting the outer and inner race so dimples are not opposite each
other won't help either because the dimple in one race is by itself a
preferred position and a new dimple will be generated in the other
race to match that location. This has all been done often before head
bearings with swiveling backing plate were introduced. As long as it
is adequately lubricated, tilting motions will be absorbed by it and
prevent bearing balls from fretting into the races.

Jobst Brandt

 

[[email protected]]

On Apr 5, 1:56 pm, jim beam <[email protected]> wrote:
> Michael Press wrote:
> >jim beam wrote:
>
> not "says me" - it's fact. bearings brinell. that's why bearing
> manufacturers are so specific about installation processes that avoid
> brinelling damage.
>
> > Sufficient but not necessary.
> > With the fork and frame locked down the bearing balls
> > do not rotate so oil does not migrate in to replenish
> > oil pumped out by vibration.
>
> "pumped out"??? repetition of jobstian over-simplification does not
> change the facts - bearings true brinell when over-loaded. end of story.

It's funny that jim beam would allude to what bearing manufacturers
say about installation, without bothering to look for what bearing
manufacturers say about false brinelling!

From SKF Bearing's FAQ on Bearing Usage:

"It is recommended that the shaft in a motor at standstill, and
subjected to vibrations, should be slowly rotated in order to avoid
damage to the bearings. Please clarify."

"When a bearing at standstill is subjected to vibrations the rolling
elements will be hammering on the same point of the raceway the whole
time. By this the lubricant will be pushed away and wear will occur
forming shallow depressions in the raceway. By rotating the shaft,
both the rolling elements and the inner ring will change position all
the time and the lubricant will stay in place. In this way this kind
of damage is prevented."

Start from www.skf.com and search a bit. You should be able to find
it, jim.

Are the bearing engineers at SKF deluded by "Jobstian
Oversimplification" too?

- Frank Krygowski

 

[RicodJour]

On Apr 5, 11:31 pm, [email protected] wrote:
>
> Some people's lives are more complicated than yours and their school
> years are too long ago to be contradicted today.

The first part of that sentence hinges on what complicated means to a
person. It's such a subjective viewpoint that it is meaningless to
compare. If you were trying to say, "I'd rather live my life than
yours", well, of course.

That last part could be interpreted several different ways - in other
words it's meaningless. What were you trying to say about people that
went to school a long time ago?

R