Minnesota Winters

jim beam wrote:

Jobst Brandt wrote:

although I have a few head sets where both top and bottom
ball bearings as well a roller bearing ones have fretting dimples.

no jobst, you have brinelling dimples. *don't protect your ignorance like
it's a virtue.

How the hell would you brinell a _top_ race, or a roller bearing
headset? Your determination to somehow declare Jobst wrong when he's
not is strange and perverse, not to mention futile.

Chalo

On Mon, 22 Dec 2008 14:51:54 -0800, Chalo wrote:

jim beam wrote:

Jobst Brandt wrote:

although I have a few head sets where both top and bottom ball
bearings as well a roller bearing ones have fretting dimples.

no jobst, you have brinelling dimples. Â*don't protect your ignorance
like it's a virtue.

How the hell would you brinell a _top_ race, or a roller bearing
headset?

er, by lateral loading perhaps? by repeated impact perhaps?


Your determination to somehow declare Jobst wrong when he's
not is strange and perverse, not to mention futile.

but he is wrong so it's not. or at least, not as futile as a guy that
hasn't done his homework trying to argue with someone that has.

bottom line, i don't understand your problem chalo. i understand jobst's
- he doesn't do his homework, but has opinions anyway, and declares those
underinformed opinions as fact. on topics where i just so happen to know
more than he does. but you? you don't seem to understand the distinction
between argument to establish fact in the face of utter bull****, and just
argument with the argument. the latter is ****ing pointless. but you
react like it's your whole raison d'etre. and as if it's personally
insulting to you. from where i'm standing, i think you're wasting your
electrons.

aka Jobst Brandt wrote:
Tom Keats wrote:

smack. Brinelled bearings. specifically unjoyous deployment of
a 4lb hammer when the car's own function can serve the purpose,
and not damage anything.

How come bottom bracket bearing do NOT have this problem when a
hammer is used to drive cotter pins in [1] and out on cranks?

[1] No, tightening is NOT done with the nut with attaching a
cottered crank.

When cotter pins have to be pounded in, there's something horribly
wrong. It usually happens from the bike shop who doesn't quite
have the exact match of what you require, and gives you what they
consider the next closest thing. It's an all too common
occurrence.

Anyway, bearings get ruined by being used dry of grease/lubricant.

I'd like to hear more about that. Who rides with lubricant free BB
bearings?

A number of Pacific Northwesters who frequently ride through deep
puddles and torrential rainfalls, and don't maintain their bikes as
well as they should for the prevailing conditions.

Besides, no matter how you brace the spindle when pounding in
cotters, the shock reaches the ball or two under the spindle. In

You shouldn't have to pound them in. If you have to pound them in,
they don't fit. Maybe tap them in a little, sure -- but to ~pound~
them in?! Nay.

I see you don't work with these. They must be pressed in with
enormous force to give enough preload and insure no "lift-off" from
the small cotter face under hard torque. Those of us who lived
through the steel crank + cotters can recall how they failed with
excess torque if not installed forcefully enough.

They must be driven in with a hammer or a special press. Not only
that, the also needed to be filed to the right wedge angle to match
the other crank in a one side replacement. The off-the-shelf cotter
not being ready to install. The flat taper was only an indication of
where the flat belonged because the threaded end was offset to pass
under the spindle flat. Again, it is a retention nut, not one that
can be used to install the cotter, it having insufficient strength for
that task.[...]

See http://www.sheldonbrown.com/var/images/var0012.jpg.

--
Tom Sherman - 42.435731,-83.985007
LOCAL CACTUS EATS CYCLIST - datakoll

Tom Sherman wrote:

smack. Brinelled bearings. specifically unjoyous deployment
of a 4lb hammer when the car's own function can serve the
purpose, and not damage anything.

How come bottom bracket bearing do NOT have this problem when a
hammer is used to drive cotter pins in [1] and out on cranks?

[1] No, tightening is NOT done with the nut with attaching a
cottered crank.

When cotter pins have to be pounded in, there's something
horribly wrong. It usually happens from the bike shop who
doesn't quite have the exact match of what you require, and
gives you what they consider the next closest thing. It's an
all too common occurrence.

Anyway, bearings get ruined by being used dry of lubricant.

I'd like to hear more about that. Who rides with lubricant free
BB bearings?

A number of Pacific Northwesters who frequently ride through deep
puddles and torrential rainfalls, and don't maintain their bikes
as well as they should for the prevailing conditions.

Besides, no matter how you brace the spindle when pounding in
cotters, the shock reaches the ball or two under the spindle. In
addition, I saw many cranks secured without more than a 1/2 lb
hammer held under the crank, yet no dents in the spindle
resulted.

I still have cottered crank spindles lying around that have no
sign of Brinelling although I have a few head sets where both top
and bottom ball bearings as well a roller bearing ones have
fretting dimples.

You shouldn't have to pound them in. If you have to pound them
in, they don't fit. Maybe tap them in a little, sure -- but to
~pound~ them in?! Nay.

I see you don't work with these. They must be pressed in with
enormous force to give enough preload and insure no "lift-off" from
the small cotter face under hard torque. Those of us who lived
through the steel crank + cotters can recall how they failed with
excess torque if not installed forcefully enough.

They must be driven in with a hammer or a special press. Not only
that, the also needed to be filed to the right wedge angle to match
the other crank in a one side replacement. The off-the-shelf
cotter not being ready to install. The flat taper was only an
indication of where the flat belonged because the threaded end was
offset to pass under the spindle flat. Again, it is a retention
nut, not one that can be used to install the cotter, it having
insufficient strength for that task.[...]

See http://www.sheldonbrown.com/var/images/var0012.jpg.

Nice item. As you can see, those were the "good old days" of bicycle
mechanics. Fortunately Sheldon saved evidence of that.

Jobst Brandt

In article ,
writes:
Tom Keats wrote:

smack. Brinelled bearings. specifically unjoyous deployment of
a 4lb hammer when the car's own function can serve the purpose,
and not damage anything.

How come bottom bracket bearing do NOT have this problem when a
hammer is used to drive cotter pins in [1] and out on cranks?

[1] No, tightening is NOT done with the nut with attaching a
cottered crank.

When cotter pins have to be pounded in, there's something horribly
wrong. It usually happens from the bike shop who doesn't quite
have the exact match of what you require, and gives you what they
consider the next closest thing. It's an all too common
occurrence.

Anyway, bearings get ruined by being used dry of grease/lubricant.

I'd like to hear more about that. Who rides with lubricant free BB
bearings?

A number of Pacific Northwesters who frequently ride through deep
puddles and torrential rainfalls, and don't maintain their bikes as
well as they should for the prevailing conditions.

Besides, no matter how you brace the spindle when pounding in
cotters, the shock reaches the ball or two under the spindle. In

You shouldn't have to pound them in. If you have to pound them in,
they don't fit. Maybe tap them in a little, sure -- but to ~pound~
them in?! Nay.

I see you don't work with these. They must be pressed in with
enormous force to give enough preload and insure no "lift-off" from
the small cotter face under hard torque. Those of us who lived
through the steel crank + cotters can recall how they failed with
excess torque if not installed forcefully enough.

I can recall dealing w/ missized/misshaped cotters because
they were all you could get. I also recall occasionally
finding the proper cotters to match the bore.

They must be driven in with a hammer or a special press.

Oh God, that's such a devastation. I just stick well-fitting
cotters in with my thumb.

Not only
that, the also needed to be filed to the right wedge angle to match
the other crank in a one side replacement. The off-the-shelf cotter
not being ready to install. The flat taper was only an indication of
where the flat belonged because the threaded end was offset to pass
under the spindle flat.

You know what's going on here -- you're trying to force the
wrong-sized/wrong-shaped cotters to do the job of the
right ones.

Again, it is a retention nut, not one that
can be used to install the cotter, it having insufficient strength for
that task.

If the cotter pin is the wrong size, of course trying
to tighten it will fsck it up. Trying to get it out
will be even worse.

addition, I saw many cranks secured without more than a 1/2 lb
hammer held under the crank, yet no dents in the spindle resulted.

Of course. The cotters were being smote with a hammer, not the
spindles. I don't think I've ever seen a dented spindle. I've seen
spindles with badly scoured cones, though. Because the bearings
were run dry of lube.

Where do you suppose the reaction force went if not through the
spindle to the bearing cups?

BBs can be done delicatately. Or at least, the violence can
be tightly mitigated. As opposed to stuck handlebar stems.

I still have cottered crank spindles lying around that have no sign
of Brinelling although I have a few head sets where both top and
bottom ball bearings as well a roller bearing ones have fretting
dimples.

In these rainy Pacific Northwest climes, the lower headset bearing
gets the brunt of the weather, especially when unprotected by a
front fender. The cup serves to guide splashed-up water into the
bearing, washing the lube out.

And it's a sneaky effect, because as long as the upper headset
bearing is fine, everything can appear to be good.

I don't think you analyzed the head bearings correctly. If they were
being bathed in water, they would rust solid when parked. On

And yet they generally don't. Go figure.


cheers,
Tom

--
Nothing is safe from me.
I'm really at:
tkeats curlicue vcn dot bc dot ca

Tom Keats wrote:

smack. Brinelled bearings. specifically unjoyous deployment
of a 4lb hammer when the car's own function can serve the
purpose, and not damage anything.

How come bottom bracket bearing do NOT have this problem when a
hammer is used to drive cotter pins in [1] and out on cranks?

[1] No, tightening is NOT done with the nut with attaching a
cottered crank.

When cotter pins have to be pounded in, there's something
horribly wrong. It usually happens from the bike shop who
doesn't quite have the exact match of what you require, and
gives you what they consider the next closest thing. It's an
all too common occurrence.

Anyway, bearings get ruined by being used dry of lubricant.

I'd like to hear more about that. Who rides with lubricant free
BB bearings?

A number of Pacific Northwesters who frequently ride through deep
puddles and torrential rainfalls, and don't maintain their bikes
as well as they should for the prevailing conditions.

Besides, no matter how you brace the spindle when pounding in
cotters, the shock reaches the ball or two under the spindle. In

You shouldn't have to pound them in. If you have to pound them
in, they don't fit. Maybe tap them in a little, sure -- but to
~pound~ them in?! Nay.

I see you don't work with these. They must be pressed in with
enormous force to give enough preload and insure no "lift-off" from
the small cotter face under hard torque. Those of us who lived
through the steel crank + cotters can recall how they failed with
excess torque if not installed forcefully enough.

I can recall dealing w/ missized/misshaped cotters because they were
all you could get. I also recall occasionally finding the proper
cotters to match the bore.

They must be driven in with a hammer or a special press.

Oh God, that's such a devastation. I just stick well-fitting
cotters in with my thumb.

I hope you didn't miss the posting showing the hammer and press for
this job, along with the special fitting for holding cotters in a vise
to file them to the appropriate flat.

Not only that, the also needed to be filed to the right wedge angle
to match the other crank in a one side replacement. The
off-the-shelf cotter not being ready to install. The flat taper
was only an indication of where the flat belonged because the
threaded end was offset to pass under the spindle flat.

You know what's going on here -- you're trying to force the
wrong-sized/wrong-shaped cotters to do the job of the right ones.

Again, you cannot be speaking from experience with these things, they
being out of use for about 30 years. What you say can be dispelled by
bicycle shop operators on this news group.

Again, it is a retention nut, not one that can be used to install
the cotter, it having insufficient strength for that task.

If the cotter pin is the wrong size, of course trying to tighten it
will **** it up. Trying to get it out will be even worse.

Don't dig yourself into a deeper hole than you were earlier. You know
not of what you speak.

In addition, I saw many cranks secured without more than a 1/2 lb
hammer held under the crank, yet no dents in the spindle
resulted.

Well at least you didn't say that you did it yourself and as a 100+ lb
rider used them without failure.

Of course. The cotters were being smote with a hammer, not the
spindles. I don't think I've ever seen a dented spindle. I've
seen spindles with badly scoured cones, though. Because the
bearings were run dry of lube.

Where do you suppose the reaction force went if not through the
spindle to the bearing cups?

BB's can be done delicately. Or at least, the violence can be
tightly mitigated. As opposed to stuck handlebar stems.

I still have cottered crank spindles lying around that have no
sign of Brinelling although I have a few head sets where both top
and bottom ball bearings as well a roller bearing ones have
fretting dimples.

In these rainy Pacific Northwest climes, the lower headset bearing
gets the brunt of the weather, especially when unprotected by a
front fender. The cup serves to guide splashed-up water into the
bearing, washing the lube out.

And it's a sneaky effect, because as long as the upper headset
bearing is fine, everything can appear to be good.

I don't think you analyzed the head bearings correctly. If they
were being bathed in water, they would rust solid when parked. On
inspection, they are not full of water and did not rust. As I
explained, this is a fretting b=problem and that is why the upper
head bearing also shows home position dimples.

And yet they generally don't. Go figure.

Your "stone wall" technique of response is not advancing your
credibility and the rest makes clear that you have no experience with
cottered crank installation.

Jobst Brandt

jim beam wrote:

Chalo wrote:

jim beam wrote:

Jobst Brandt wrote:

although I have a few head sets where both top and bottom ball
bearings as well a roller bearing ones have fretting dimples.

no jobst, you have brinelling dimples. *don't protect your ignorance
like it's a virtue.

How the hell would you brinell a _top_ race, or a roller bearing
headset?

er, by lateral loading perhaps? *by repeated impact perhaps?

If your headset is made out of cream cheese, sure. But here in the
real world where we use headsets with hardened steel races, there is
no impact that you can transfer through a tire, or tolerate at the
handgrips, that will brinell a headset-- unless you mean false
brinelling. If headset races were that soft, I would use them up at a
far higher rate than other riders (since I'm much heavier than other
riders). In fact I use headsets for many years before they wear out
and begin to index.

Headset indentation from false brinelling is gradual and progressive.
If it were true brinelling, it would appear suddenly after a single
transient overload.

Chalo

Tom Keats wrote:
In article ,
writes:
Tom Keats wrote:

smack. Brinelled bearings. specifically unjoyous deployment of
a 4lb hammer when the car's own function can serve the purpose,
and not damage anything.
How come bottom bracket bearing do NOT have this problem when a
hammer is used to drive cotter pins in [1] and out on cranks?
[1] No, tightening is NOT done with the nut with attaching a
cottered crank.
When cotter pins have to be pounded in, there's something horribly
wrong. It usually happens from the bike shop who doesn't quite
have the exact match of what you require, and gives you what they
consider the next closest thing. It's an all too common
occurrence.
Anyway, bearings get ruined by being used dry of grease/lubricant.
I'd like to hear more about that. Who rides with lubricant free BB
bearings?
A number of Pacific Northwesters who frequently ride through deep
puddles and torrential rainfalls, and don't maintain their bikes as
well as they should for the prevailing conditions.
Besides, no matter how you brace the spindle when pounding in
cotters, the shock reaches the ball or two under the spindle. In
You shouldn't have to pound them in. If you have to pound them in,
they don't fit. Maybe tap them in a little, sure -- but to ~pound~
them in?! Nay.
I see you don't work with these. They must be pressed in with
enormous force to give enough preload and insure no "lift-off" from
the small cotter face under hard torque. Those of us who lived
through the steel crank + cotters can recall how they failed with
excess torque if not installed forcefully enough.

I can recall dealing w/ missized/misshaped cotters because
they were all you could get. I also recall occasionally
finding the proper cotters to match the bore.

They must be driven in with a hammer or a special press.

Oh God, that's such a devastation. I just stick well-fitting
cotters in with my thumb.

Not only
that, the also needed to be filed to the right wedge angle to match
the other crank in a one side replacement. The off-the-shelf cotter
not being ready to install. The flat taper was only an indication of
where the flat belonged because the threaded end was offset to pass
under the spindle flat.

You know what's going on here -- you're trying to force the
wrong-sized/wrong-shaped cotters to do the job of the
right ones.

Again, it is a retention nut, not one that
can be used to install the cotter, it having insufficient strength for
that task.

If the cotter pin is the wrong size, of course trying
to tighten it will fsck it up. Trying to get it out
will be even worse.

addition, I saw many cranks secured without more than a 1/2 lb
hammer held under the crank, yet no dents in the spindle resulted.
Of course. The cotters were being smote with a hammer, not the
spindles. I don't think I've ever seen a dented spindle. I've seen
spindles with badly scoured cones, though. Because the bearings
were run dry of lube.
Where do you suppose the reaction force went if not through the
spindle to the bearing cups?

BBs can be done delicatately. Or at least, the violence can
be tightly mitigated. As opposed to stuck handlebar stems.

I still have cottered crank spindles lying around that have no sign
of Brinelling although I have a few head sets where both top and
bottom ball bearings as well a roller bearing ones have fretting
dimples.
In these rainy Pacific Northwest climes, the lower headset bearing
gets the brunt of the weather, especially when unprotected by a
front fender. The cup serves to guide splashed-up water into the
bearing, washing the lube out.
And it's a sneaky effect, because as long as the upper headset
bearing is fine, everything can appear to be good.
I don't think you analyzed the head bearings correctly. If they were
being bathed in water, they would rust solid when parked. On

And yet they generally don't. Go figure.


cheers,
Tom


The manufacturers of steel pinned cranks seem to feel a heavy cast steel
press with 42:1 leverage driven forcefully ( an able man puts out about
80 pounds with both arms just below shoulder height) is a better
approach. That is a humongous amount of pressure.

Here are two clever designs, a VAR #7 crank press and a set of S+S couplers:
http://www.yellowjersey.org/photosfromthepast/VAR07.JPG

When these cranks were still common, even new premium quality Sugino
cranks on Sugino spindles would fail in a day or two of riding when the
assembler neglected to remove, lubricate and press the pins properly.

Although one might get a small amount of pin/spindle contact by drawing
up the nut, the forces at that contact will work it free and deform the
pin's surface in short order if the pin moves at all.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971
** Posted from http://www.teranews.com **

Andrew Muzi wrote:

smack. Brinelled bearings. specifically unjoyous deployment
of a 4lb hammer when the car's own function can serve the
purpose, and not damage anything.

How come bottom bracket bearing do NOT have this problem when
a hammer is used to drive cotter pins in [1] and out on
cranks? [1] No, tightening is NOT done with the nut with
attaching a cottered crank.

When cotter pins have to be pounded in, there's something
horribly wrong. It usually happens from the bike shop who
doesn't quite have the exact match of what you require, and
gives you what they consider the next closest thing. It's an
all too common occurrence.

Anyway, bearings get ruined by being used dry of lubricant.

I'd like to hear more about that. Who rides with lubricant free
BB bearings?

A number of Pacific Northwesters who frequently ride through deep
puddles and torrential rainfalls, and don't maintain their bikes
as well as they should for the prevailing conditions.

Besides, no matter how you brace the spindle when pounding in
cotters, the shock reaches the ball or two under the spindle.
In

You shouldn't have to pound them in. If you have to pound them
in, they don't fit. Maybe tap them in a little, sure -- but to
~pound~ them in?! Nay.

I see you don't work with these. They must be pressed in with
enormous force to give enough preload and insure no "lift-off"
from the small cotter face under hard torque. Those of us who
lived through the steel crank + cotters can recall how they failed
with excess torque if not installed forcefully enough.

I can recall dealing w/ missized/misshaped cotters because they
were all you could get. I also recall occasionally finding the
proper cotters to match the bore.

They must be driven in with a hammer or a special press.

Oh God, that's such a devastation. I just stick well-fitting
cotters in with my thumb.

Not only that, they also needed to be filed to the right wedge
angle to match the other crank in a one side replacement. The
off-the-shelf cotter not being ready to install. The flat taper
was only an indication of where the flat belonged because the
threaded end was offset to pass under the spindle flat.

You know what's going on here -- you're trying to force the
wrong-sized/wrong-shaped cotters to do the job of the right ones.

Again, it is a retention nut, not one that can be used to install
the cotter, it having insufficient strength for that task.

If the cotter pin is the wrong size, of course trying to tighten it
will **** it up. Trying to get it out will be even worse.

In addition, I saw many cranks secured without more than a 1/2 lb
hammer held under the crank, yet no dents in the spindle
resulted. Of course. The cotters were being smote with a
hammer, not the spindles. I don't think I've ever seen a dented
spindle. I've seen spindles with badly scoured cones, though.
Because the bearings were run dry of lube.

Where do you suppose the reaction force went if not through the
spindle to the bearing cups?

BB's can be done delicately. Or at least, the violence can be
tightly mitigated. As opposed to stuck handlebar stems.

I still have cottered crank spindles lying around that have no
sign of Brinelling although I have a few head sets where both
top and bottom ball bearings as well a roller bearing ones have
fretting dimples.

In these rainy Pacific Northwest climes, the lower headset
bearing gets the brunt of the weather, especially when
unprotected by a front fender. The cup serves to guide
splashed-up water into the bearing, washing the lube out. And
it's a sneaky effect, because as long as the upper headset
bearing is fine, everything can appear to be good.

I don't think you analyzed the head bearings correctly. If they
were being bathed in water, they would rust solid when parked. On
inspection, they are not full of water and did not rust. As I
explained, this is a fretting problem and that is why the upper
head bearing also shows home position dimples.

And yet they generally don't. Go figure.

The manufacturers of steel pinned cranks seem to feel a heavy cast
steel press with 42:1 leverage driven forcefully ( an able man puts
out about 80 pounds with both arms just below shoulder height) is a
better approach. That is a humongous amount of pressure.

Here are two clever designs, a VAR #7 crank press and a set of S+S
couplers:

http://www.yellowjersey.org/photosfromthepast/VAR07.JPG

When these cranks were still common, even new premium quality Sugino
cranks on Sugino spindles would fail in a day or two of riding when
the assembler neglected to remove, lubricate and press the pins
properly.

Although one might get a small amount of pin/spindle contact by
drawing up the nut, the forces at that contact will work it free and
deform the pin's surface in short order if the pin moves at all.

Those of us who rode with that old stuff, learned the hard way that
unless they have special tooling to shape cotters, one must replace
them in pairs to insure that the angle of the flat is the same on both
or the cranks won't be 180° apart. Also, the slope of the flat should
be as low as possible so the contact with the spindle-flat will have
grater contact at the narrow end of that elliptical surface.

It's nice to see the actual tool, mine is long gone because I gave it
to a friend who still had the old cranks when I switched to aluminum
with square taper. He rode Cinelli cranks that were actually
Magistroni.

http://www.sheldonbrown.com/var/pages/var0012.html

Jobst Brandt

In article ,
writes:
Andrew Muzi wrote:

smack. Brinelled bearings. specifically unjoyous deployment
of a 4lb hammer when the car's own function can serve the
purpose, and not damage anything.

How come bottom bracket bearing do NOT have this problem when
a hammer is used to drive cotter pins in [1] and out on
cranks? [1] No, tightening is NOT done with the nut with
attaching a cottered crank.

When cotter pins have to be pounded in, there's something
horribly wrong. It usually happens from the bike shop who
doesn't quite have the exact match of what you require, and
gives you what they consider the next closest thing. It's an
all too common occurrence.

Anyway, bearings get ruined by being used dry of lubricant.

I'd like to hear more about that. Who rides with lubricant free
BB bearings?

A number of Pacific Northwesters who frequently ride through deep
puddles and torrential rainfalls, and don't maintain their bikes
as well as they should for the prevailing conditions.

Besides, no matter how you brace the spindle when pounding in
cotters, the shock reaches the ball or two under the spindle.
In

You shouldn't have to pound them in. If you have to pound them
in, they don't fit. Maybe tap them in a little, sure -- but to
~pound~ them in?! Nay.

I see you don't work with these. They must be pressed in with
enormous force to give enough preload and insure no "lift-off"
from the small cotter face under hard torque. Those of us who
lived through the steel crank + cotters can recall how they failed
with excess torque if not installed forcefully enough.

I can recall dealing w/ missized/misshaped cotters because they
were all you could get. I also recall occasionally finding the
proper cotters to match the bore.

They must be driven in with a hammer or a special press.

Oh God, that's such a devastation. I just stick well-fitting
cotters in with my thumb.

Not only that, they also needed to be filed to the right wedge
angle to match the other crank in a one side replacement. The
off-the-shelf cotter not being ready to install. The flat taper
was only an indication of where the flat belonged because the
threaded end was offset to pass under the spindle flat.

You know what's going on here -- you're trying to force the
wrong-sized/wrong-shaped cotters to do the job of the right ones.

Again, it is a retention nut, not one that can be used to install
the cotter, it having insufficient strength for that task.

If the cotter pin is the wrong size, of course trying to tighten it
will **** it up. Trying to get it out will be even worse.

In addition, I saw many cranks secured without more than a 1/2 lb
hammer held under the crank, yet no dents in the spindle
resulted. Of course. The cotters were being smote with a
hammer, not the spindles. I don't think I've ever seen a dented
spindle. I've seen spindles with badly scoured cones, though.
Because the bearings were run dry of lube.

Where do you suppose the reaction force went if not through the
spindle to the bearing cups?

BB's can be done delicately. Or at least, the violence can be
tightly mitigated. As opposed to stuck handlebar stems.

I still have cottered crank spindles lying around that have no
sign of Brinelling although I have a few head sets where both
top and bottom ball bearings as well a roller bearing ones have
fretting dimples.

In these rainy Pacific Northwest climes, the lower headset
bearing gets the brunt of the weather, especially when
unprotected by a front fender. The cup serves to guide
splashed-up water into the bearing, washing the lube out. And
it's a sneaky effect, because as long as the upper headset
bearing is fine, everything can appear to be good.

I don't think you analyzed the head bearings correctly. If they
were being bathed in water, they would rust solid when parked. On
inspection, they are not full of water and did not rust. As I
explained, this is a fretting problem and that is why the upper
head bearing also shows home position dimples.

And yet they generally don't. Go figure.

The manufacturers of steel pinned cranks seem to feel a heavy cast
steel press with 42:1 leverage driven forcefully ( an able man puts
out about 80 pounds with both arms just below shoulder height) is a
better approach. That is a humongous amount of pressure.

Here are two clever designs, a VAR #7 crank press and a set of S+S
couplers:

http://www.yellowjersey.org/photosfromthepast/VAR07.JPG

When these cranks were still common, even new premium quality Sugino
cranks on Sugino spindles would fail in a day or two of riding when
the assembler neglected to remove, lubricate and press the pins
properly.

Although one might get a small amount of pin/spindle contact by
drawing up the nut, the forces at that contact will work it free and
deform the pin's surface in short order if the pin moves at all.

Those of us who rode with that old stuff, learned the hard way that
unless they have special tooling to shape cotters, one must replace
them in pairs to insure that the angle of the flat is the same on both
or the cranks won't be 180=C2=B0 apart.

My father was a jeweller/watchmaker/metalsmithing guy.
So I had access to a Simpson[tm] screw-cutter lathe,
and some education as to how to use it imaginatively.
It was some antique with numerous interchangeable
cogwheels.

My father's pet peeve was poorly-finished metal components
with burrs & in-the-way tool marks still on them, and his
nemesis was egregious swage-fitting.


cheers,
Tom

--
Nothing is safe from me.
I'm really at:
tkeats curlicue vcn dot bc dot ca