PTFE tape...

Bill Westphal said:

I'm not sure what this has to do with that white tape I used to
erroneously wrap on my titanium pedal threads before I saw the light
and converted to anti-seize. No creaking yet, so it may be a
keeper.

Quoted message said:

http://www.lib.niu.edu/ipo/2002/ip020317.html

The reason some metals gall more readily than others is that fretting
friction induces high temperatures at asperity contacts that weld and
break, leaving behind wear debris, ultimately welding the joint in
many places. Stainless steels and titanium, are both poor thermal
conductors, exacerbating the condition. For this reason these metals
are more difficult to machine. Typically, a shallow cut makes the
second pass of the cutting tool run into preheated material that soon
burns the cutting edge... which generates more heat as the dull tool
plows though the metal.

Jobst Brandt

Quoted message said:

Bill Westphal said:

I'm not sure what this has to do with that white tape I used to
erroneously wrap on my titanium pedal threads before I saw the light
and converted to anti-seize. No creaking yet, so it may be a
keeper.

Quoted message said:

http://www.lib.niu.edu/ipo/2002/ip020317.html

The reason some metals gall more readily than others is that fretting
friction induces high temperatures

bull. that may be the case where there's a high relative speed between
two surfaces and where heat generation exceeds dispersion, but for a
near-static bearing cup on a bike? that's one of your finer flights of
underinformed fantasy.

Quoted message said:

at asperity contacts that weld and
break, leaving behind wear debris, ultimately welding the joint in
many places.

yes, but that's nothing to do with temperature. you need to look into
solid state diffusion some time.

Quoted message said:

Stainless steels and titanium, are both poor thermal
conductors, exacerbating the condition.

stainless doesn't cold weld. titanium does. like i said, you need to
look into solid state diffusion some time.

Quoted message said:

For this reason these metals
are more difficult to machine.

oh, please. yes, ti is difficult to machine, but ss isn't. and it's
got nothing to do with thermal conductivity. you need to look into
crystallography, slip planes, precipitation, etc. unbelievable
presumptive nonsense.

Quoted message said:

Typically, a shallow cut makes the
second pass of the cutting tool run into preheated material that soon
burns the cutting edge...

second pass??? jobst, exactly what kind of heat do you think gets
retained? have you /ever/ studied materials or even machining in any way?

Quoted message said:

which generates more heat as the dull tool
plows though the metal.

ok, let's assume that tool speed has /nothing/ to do with machining
results [which of course it does], have you any idea what might be any
/other/ reason for a so-called "dull" tool? could there perhaps
possibly be any factor other than heat? and why are ceramics so
successful as tools? i'm really looking forward to this one!

Jasper Janssen said:

On Sun, 07 Jan 2007 00:58:51 -0700, Bill Westphal <[email hidden]>

Quoted message said:

There was a manufactured gas plant in my old home town Oak Park, IL from
1896-1924, at which point they created a park on the site. In 1999 they

Did they move the plant elsewhere in 1924? My hometown's gas works was
operating on its site until the 50s, and stood there another decade or so
derelict. It was torn down eventually and the site became a fenced-off
jungle, with recently at the end of the 90s it finally getting cleaned up
and turned into a park. When I was growing up, it was where you illicitly
went to make things burn.

Jasper

By that point the location was pretty much smack dab in the middle of
the then 2'nd largest metropolitan area in the country, so I imagine
they moved the show to the new sticks, creating toxic wastes in someone
else's soon-to-be backyard, further spreading the filth. It wouldn't be
fair to allow one group or location to hog it all up for themselves.

Bill Westphal

jim beam said:

oh, please. yes, ti is difficult to machine, but ss isn't. and it's
got nothing to do with thermal conductivity. you need to look into
crystallography, slip planes, precipitation, etc. unbelievable
presumptive nonsense.

Typical mumbo-jumbo.

http://www.askzn.co.za/tech/tech_fab_machin.htm

"Columbus ferritic grades are usually supplied in the annealed condition
and due to their toughness their machining characteristics are more
similar to low alloy carbon steels rather than mild steels. Due to the
difference in conductivity, care must be taken to ensure adequate
removal heat from the workpiece and the tool. Overheating can result in
blunting of the tool and localized burning of the workpiece surface."

"Columbus austenitic grades are also normally supplied in the annealed
condition ... As conductivity is even lower than for ferritic grades,
heat removal is of greater importance."

"When machining stainless steels note must be taken of the following:

6. The largest possible tool must be used in order to dissipate heat."

Peter Cole said:

jim beam said:

oh, please. yes, ti is difficult to machine, but ss isn't. and it's
got nothing to do with thermal conductivity. you need to look into
crystallography, slip planes, precipitation, etc. unbelievable
presumptive nonsense.

Typical mumbo-jumbo.

http://www.askzn.co.za/tech/tech_fab_machin.htm

"Columbus ferritic grades are usually supplied in the annealed condition
and due to their toughness their machining characteristics are more
similar to low alloy carbon steels rather than mild steels. Due to the
difference in conductivity, care must be taken to ensure adequate
removal heat from the workpiece and the tool. Overheating can result in
blunting of the tool and localized burning of the workpiece surface."

"Columbus austenitic grades are also normally supplied in the annealed
condition ... As conductivity is even lower than for ferritic grades,
heat removal is of greater importance."

"When machining stainless steels note must be taken of the following:

6. The largest possible tool must be used in order to dissipate heat."

which affects the feed rate - big deal. besides, i'm not claiming that
machining operations don't generate heat - of course they do. but i
/am/ telling you that asperity welding for a bearing cup in bb does
/not/ involve heat - which judging by your silence on the subject is a
red herring you seem to have swallowed.

jim beam said:

Peter Cole said:

jim beam said:

oh, please. yes, ti is difficult to machine, but ss isn't. and it's
got nothing to do with thermal conductivity. you need to look into
crystallography, slip planes, precipitation, etc. unbelievable
presumptive nonsense.

Typical mumbo-jumbo.

http://www.askzn.co.za/tech/tech_fab_machin.htm

"Columbus ferritic grades are usually supplied in the annealed
condition and due to their toughness their machining characteristics
are more similar to low alloy carbon steels rather than mild steels.
Due to the difference in conductivity, care must be taken to ensure
adequate removal heat from the workpiece and the tool. Overheating can
result in blunting of the tool and localized burning of the workpiece
surface."

"Columbus austenitic grades are also normally supplied in the annealed
condition ... As conductivity is even lower than for ferritic grades,
heat removal is of greater importance."

"When machining stainless steels note must be taken of the following:

6. The largest possible tool must be used in order to dissipate heat."

which affects the feed rate - big deal. besides, i'm not claiming that
machining operations don't generate heat - of course they do. but i
/am/ telling you that asperity welding for a bearing cup in bb does
/not/ involve heat - which judging by your silence on the subject is a
red herring you seem to have swallowed.

Dodge, weave, usual BS. You did notice the repeated use of the word
"conductivity"?

Wild turkey said:

Quoted message said:

Quoted message said:

oh, please. yes, ti is difficult to machine, but ss isn't. and it's
got nothing to do with thermal conductivity. you need to look into
crystallography, slip planes, precipitation, etc. unbelievable
presumptive nonsense.

Quoted message said:

Quoted message said:

Typical mumbo-jumbo.

http://www.askzn.co.za/tech/tech_fab_machin.htm

# Columbus ferritic grades are usually supplied in the annealed
# condition and due to their toughness their machining characteristics
# are more similar to low alloy carbon steels rather than mild steels.
# Due to the difference in conductivity, care must be taken to ensure
# adequate removal heat from the workpiece and the tool. Overheating
# can result in blunting of the tool and localized burning of the
# workpiece surface.

# Columbus austenitic grades are also normally supplied in the
# annealed condition... As conductivity is even lower than for
# ferritic grades, heat removal is of greater importance.

# "When machining stainless steels note must be taken of the following:

# 6. The largest possible tool must be used in order to dissipate heat."

Quoted message said:

which affects the feed rate - big deal. besides, i'm not claiming that
machining operations don't generate heat - of course they do. but i
/am/ telling you that asperity welding for a bearing cup in bb does
/not/ involve heat - which judging by your silence on the subject is a
red herring you seem to have swallowed.

You might read the proceedings of the STLE papers in which the flash
temperatures of unlubricated surfaces at asperity contacts is
experimentally assessed. This explains the effect that in the absence
of lubricants, one or both sliding surfaces reach melting temperatures
at these points as the material shears and that this is the mechanism
for welding (seizing) between materials.

http://www.stle.org/

Dissimilar materials in industry are welded by this effect with
practically no heat affected zone in which material properties are
weakened. The process is variably called inertia or friction welding.
This is commonly used to connect carbon steel clevises to stainless
hydraulic piston rods on construction machinery.

http://www.interfacewelding.com/

Jobst Brandt

Quoted message said:

Wild turkey said:

Quoted message said:

> oh, please. yes, ti is difficult to machine, but ss isn't. and it's
> got nothing to do with thermal conductivity. you need to look into
> crystallography, slip planes, precipitation, etc. unbelievable
> presumptive nonsense.

Quoted message said:

Quoted message said:

Typical mumbo-jumbo.

http://www.askzn.co.za/tech/tech_fab_machin.htm

# Columbus ferritic grades are usually supplied in the annealed
# condition and due to their toughness their machining characteristics
# are more similar to low alloy carbon steels rather than mild steels.
# Due to the difference in conductivity, care must be taken to ensure
# adequate removal heat from the workpiece and the tool. Overheating
# can result in blunting of the tool and localized burning of the
# workpiece surface.

# Columbus austenitic grades are also normally supplied in the
# annealed condition... As conductivity is even lower than for
# ferritic grades, heat removal is of greater importance.

# "When machining stainless steels note must be taken of the following:

# 6. The largest possible tool must be used in order to dissipate heat."

Quoted message said:

which affects the feed rate - big deal. besides, i'm not claiming that
machining operations don't generate heat - of course they do. but i
/am/ telling you that asperity welding for a bearing cup in bb does
/not/ involve heat - which judging by your silence on the subject is a
red herring you seem to have swallowed.

You might read the proceedings of the STLE papers in which the flash
temperatures of unlubricated surfaces at asperity contacts is
experimentally assessed. This explains the effect that in the absence
of lubricants, one or both sliding surfaces reach melting temperatures
at these points as the material shears and that this is the mechanism
for welding (seizing) between materials.

http://www.stle.org/

Dissimilar materials in industry are welded by this effect with
practically no heat affected zone in which material properties are
weakened. The process is variably called inertia or friction welding.
This is commonly used to connect carbon steel clevises to stainless
hydraulic piston rods on construction machinery.

http://www.interfacewelding.com/

this is one of your worst moments of underinformed presumption.
friction welding is old hat and well researched. but at no time is that
applicable to a bb cup/shell interface - the shear rate is just /way/
too low. in the examples you cite, shear rate is high enough to evolve
heat at a greater rate than it's conducted away from contact and local
melting occurs.

for the bb situation, there are these two things called cold welding and
diffusion. neither have to involve any form of heat or liquidus, simply
intimate contact and pressure.

http://www.read-wca.com/pwm.cfm
gives a good explanation of cold pressure welding and the nature of bonding.

http://www.forengineers.org/cgi-bin/wrcbulletin/bulletin.pl?action=view;page=2;id=120
in this article, heat is cited as part of diffusion welding because
bonding needs to occur in a commercially acceptable time frame. if
otoh, you have time on your hands, you can just wait. like screwing
threads together and leaving them.

Peter Cole said:

jim beam said:

Peter Cole said:

jim beam wrote:

> oh, please. yes, ti is difficult to machine, but ss isn't. and
> it's got nothing to do with thermal conductivity. you need to look
> into crystallography, slip planes, precipitation, etc. unbelievable
> presumptive nonsense.

Typical mumbo-jumbo.

http://www.askzn.co.za/tech/tech_fab_machin.htm

"Columbus ferritic grades are usually supplied in the annealed
condition and due to their toughness their machining characteristics
are more similar to low alloy carbon steels rather than mild steels.
Due to the difference in conductivity, care must be taken to ensure
adequate removal heat from the workpiece and the tool. Overheating
can result in blunting of the tool and localized burning of the
workpiece surface."

"Columbus austenitic grades are also normally supplied in the
annealed condition ... As conductivity is even lower than for
ferritic grades, heat removal is of greater importance."

"When machining stainless steels note must be taken of the following:

6. The largest possible tool must be used in order to dissipate heat."

which affects the feed rate - big deal. besides, i'm not claiming
that machining operations don't generate heat - of course they do.
but i /am/ telling you that asperity welding for a bearing cup in bb
does /not/ involve heat - which judging by your silence on the subject
is a red herring you seem to have swallowed.

Dodge, weave, usual BS. You did notice the repeated use of the word
"conductivity"?

did /you/ figure out context of "conductivity"? it doesn't look like
it. see my response to brandt.

jim beam said:

for the bb situation, there are these two things called cold welding and
diffusion. neither have to involve any form of heat or liquidus, simply
intimate contact and pressure.

http://www.read-wca.com/pwm.cfm
gives a good explanation of cold pressure welding and the nature of
bonding.

Did you even read that article?

"Cold pressure welding is restricted to non-ferrous materials, or to
soft iron that has no carbon content."

Peter Cole said:

jim beam said:

for the bb situation, there are these two things called cold welding and
diffusion. neither have to involve any form of heat or liquidus, simply
intimate contact and pressure.

http://www.read-wca.com/pwm.cfm
gives a good explanation of cold pressure welding and the nature of
bonding.

Did you even read that article?

"Cold pressure welding is restricted to non-ferrous materials, or to
soft iron that has no carbon content."

"jim beam" has a history of posting links claiming that they support
his position; but when you actually go there, they don't.

A charitable person might say that this was kind of a "support through
obfuscation" approach to debate - if it were only once...

Quoted message said:

Peter Cole said:

jim beam said:

for the bb situation, there are these two things called cold welding and
diffusion. neither have to involve any form of heat or liquidus, simply
intimate contact and pressure.

http://www.read-wca.com/pwm.cfm
gives a good explanation of cold pressure welding and the nature of
bonding.

Did you even read that article?

"Cold pressure welding is restricted to non-ferrous materials, or to
soft iron that has no carbon content."

"jim beam" has a history of posting links claiming that they support
his position; but when you actually go there, they don't.

A charitable person might say that this was kind of a "support through
obfuscation" approach to debate - if it were only once...

Ritalin, anyone?

Peter Cole said:

jim beam said:

for the bb situation, there are these two things called cold welding
and diffusion. neither have to involve any form of heat or liquidus,
simply intimate contact and pressure.

http://www.read-wca.com/pwm.cfm
gives a good explanation of cold pressure welding and the nature of
bonding.

Did you even read that article?

"Cold pressure welding is restricted to non-ferrous materials, or to
soft iron that has no carbon content."

that should read "cold pressure welding is 'generally' restricted..."

besides, did you bother to read about diffusion? and did you check into
the teensy-weensy little issue about shear rates vs. heat evolution?

jim beam said:

Peter Cole said:

jim beam said:

for the bb situation, there are these two things called cold welding
and diffusion. neither have to involve any form of heat or liquidus,
simply intimate contact and pressure.

http://www.read-wca.com/pwm.cfm
gives a good explanation of cold pressure welding and the nature of
bonding.

Did you even read that article?

"Cold pressure welding is restricted to non-ferrous materials, or to
soft iron that has no carbon content."

that should read "cold pressure welding is 'generally' restricted..."

Hey, it's your cite, maybe you should e-mail the author to tell them
they're wrong.

Quoted message said:

besides, did you bother to read about diffusion?

Sure, it doesn't apparently work for steel, either.

Quoted message said:

and did you check into
the teensy-weensy little issue about shear rates vs. heat evolution?

That's your issue. I think the proof's on you. Jobst's explanation
matches my understanding, and you haven't introduced anything yet to
challenge it.

Quoted message said:

http://www.read-wca.com/pwm.cfm

Quoted message said:

From what this article surmises, one
can imagine that two optically smooth pieces of steel would in time
become welded if resting on one another. That does not occur without
motion between the two.

I think they *would* become welded in the absence of motion. Add
pressure and heat to speed the process, and you get diffusion bonding.
Here are some references to diffusion bonding stainless steel:

<http://scholar.google.com/scholar?q=diffusion+bond+stainless+steel&hl=en&lr=&btnG=Search>

I don't know if this type of bonding plays a role in headsets and bottom
brackets.

--
Dave
dvt at psu dot edu

Everyone confesses that exertion which brings out all the powers of body
and mind is the best thing for us; but most people do all they can to
get rid of it, and as a general rule nobody does much more than
circumstances drive them to do. -Harriet Beecher Stowe, abolitionist and
novelist (1811-1896)

dvt said:

Quoted message said:

http://www.read-wca.com/pwm.cfm

Quoted message said:

From what this article surmises, one
can imagine that two optically smooth pieces of steel would in time
become welded if resting on one another. That does not occur without
motion between the two.

I think they *would* become welded in the absence of motion. Add
pressure and heat to speed the process, and you get diffusion bonding.
Here are some references to diffusion bonding stainless steel:

<http://scholar.google.com/scholar?q=diffusion+bond+stainless+steel&hl=en&lr=&btnG=Search>

I don't know if this type of bonding plays a role in headsets and bottom
brackets.

Find one that's steel-to-steel.

Peter Cole said:

dvt said:

Quoted message said:

http://www.read-wca.com/pwm.cfm

Quoted message said:

From what this article surmises, one
can imagine that two optically smooth pieces of steel would in time
become welded if resting on one another. That does not occur without
motion between the two.

I think they *would* become welded in the absence of motion. Add
pressure and heat to speed the process, and you get diffusion bonding.
Here are some references to diffusion bonding stainless steel:

<http://scholar.google.com/scholar?q=diffusion+bond+stainless+steel&hl=en&lr=&btnG=Search>

I don't know if this type of bonding plays a role in headsets and
bottom brackets.

Find one that's steel-to-steel.

A slight modification of the search terms...

<http://scholar.google.com/scholar?hl=en&lr=&q=diffusion+bond+%22steel+to+steel%22&btnG=Search>

I looked at the first link returned. Or perhaps you prefer...

<http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TW2-3YWX3V2-3H&_coverDate=03%2F31%2F2000&_alid=521906506&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5550&_sort=d&view=c&_acct=C000014439&_version=1&_urlVersion=0&_userid=209810&md5=455395599933954c66bdb122b2ac330c>

From that paper:

"Crucible S7 tool steel was... prepared in a vacuum hot press using bond
conditions of 1100°C and 10, 5 and 20 MPa (Samples 1, 2 and 3) for 20 min."

--
Dave
dvt at psu dot edu

Everyone confesses that exertion which brings out all the powers of body
and mind is the best thing for us; but most people do all they can to
get rid of it, and as a general rule nobody does much more than
circumstances drive them to do. -Harriet Beecher Stowe, abolitionist and
novelist (1811-1896)

dvt said:

I looked at the first link returned. Or perhaps you prefer...

<http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TW2-3YWX3V2-3H&_coverDate=03%2F31%2F2000&_alid=521906506&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5550&_sort=d&view=c&_acct=C000014439&_version=1&_urlVersion=0&_userid=209810&md5=455395599933954c66bdb122b2ac330c>

From that paper:

"Crucible S7 tool steel was... prepared in a vacuum hot press using bond
conditions of 1100°C and 10, 5 and 20 MPa (Samples 1, 2 and 3) for 20 min."

And to think I thought it was hot where I ride!

dvt said:

Peter Cole said:

dvt said:

[email hidden] wrote:
> http://www.read-wca.com/pwm.cfm

> From what this article surmises, one
> can imagine that two optically smooth pieces of steel would in time
> become welded if resting on one another. That does not occur without
> motion between the two.

I think they *would* become welded in the absence of motion. Add
pressure and heat to speed the process, and you get diffusion
bonding. Here are some references to diffusion bonding stainless steel:

<http://scholar.google.com/scholar?q=diffusion+bond+stainless+steel&hl=en&lr=&btnG=Search>

I don't know if this type of bonding plays a role in headsets and
bottom brackets.

Find one that's steel-to-steel.

A slight modification of the search terms...

<http://scholar.google.com/scholar?hl=en&lr=&q=diffusion+bond+%22steel+to+steel%22&btnG=Search>

I looked at the first link returned. Or perhaps you prefer...

<http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TW2-3YWX3V2-3H&_coverDate=03%2F31%2F2000&_alid=521906506&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5550&_sort=d&view=c&_acct=C000014439&_version=1&_urlVersion=0&_userid=209810&md5=455395599933954c66bdb122b2ac330c>

From that paper:

"Crucible S7 tool steel was... prepared in a vacuum hot press using bond
conditions of 1100°C and 10, 5 and 20 MPa (Samples 1, 2 and 3) for 20 min."

I can't read either -- the first is illegible, the second requires
membership.

In any case, yes, you can bond steel to steel in a vacuum, even without
all the temperature and pressure, I knew that, but that isn't going to
happen in a bottom bracket bearing.

Peter Cole said:

dvt said:

Peter Cole said:

dvt wrote:
> [email hidden] wrote:
>> http://www.read-wca.com/pwm.cfm
>
>> From what this article surmises, one
>> can imagine that two optically smooth pieces of steel would in time
>> become welded if resting on one another. That does not occur without
>> motion between the two.
>
> I think they *would* become welded in the absence of motion. Add
> pressure and heat to speed the process, and you get diffusion
> bonding. Here are some references to diffusion bonding stainless steel:
>
> <http://scholar.google.com/scholar?q=diffusion+bond+stainless+steel&hl=en&lr=&btnG=Search>
>
>
> I don't know if this type of bonding plays a role in headsets and
> bottom brackets.
>

Find one that's steel-to-steel.

A slight modification of the search terms...

<http://scholar.google.com/scholar?hl=en&lr=&q=diffusion+bond+%22steel+to+steel%22&btnG=Search>

I looked at the first link returned. Or perhaps you prefer...

<http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TW2-3YWX3V2-3H&_coverDate=03%2F31%2F2000&_alid=521906506&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5550&_sort=d&view=c&_acct=C000014439&_version=1&_urlVersion=0&_userid=209810&md5=455395599933954c66bdb122b2ac330c>

From that paper:

"Crucible S7 tool steel was... prepared in a vacuum hot press using
bond conditions of 1100°C and 10, 5 and 20 MPa (Samples 1, 2 and 3)
for 20 min."

I can't read either -- the first is illegible, the second requires
membership.

In any case, yes, you can bond steel to steel in a vacuum, even without
all the temperature and pressure, I knew that, but that isn't going to
happen in a bottom bracket bearing.

really? how'd you figure that? actually, it can happen in a bottom
bracket bearing cup, just like it's one of the mechanisms in false
brinelling. but you knew that too didn't you.