Minnesota Winters

On Sun, 28 Dec 2008 03:29:26 +0000, jobst.brandt wrote:

Tom Keats wrote:

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.

For forcing barrel-chested or wrongly-sized cotter pins into
straight-tapered holes, I'm not surprised.

You are conjuring up unreal circumstances. The Best cotters were from
"Acier Dupratnik" and were of high strength steel. Just the same, they
were designed to be filed or machined to identical flats

yeah, good luck on the fantasy of /that/ ever being achieved.



and they could
be pushed through the bare crank with little effort. The press fit
comes when the spindle is in the crank and the cotter inserted to arrest
it in a rotationally fixed position that must be identical for both
cranks or sprinting would impractical.

red herring.




But cotter pins are not barrel-chested. I actually have a few in my
stock -- I've slid dial calipers down them, and there's no widening in
their middles. Straight taper pins; straight taper holes. As it
should be, as long as there's a perfect fit with no slop.

It would be unimaginable that Acier Dupratnik would go to all the
trouble of machining these cotters from high grade steel bar stock that
wasn't straight.

eh? what's that got to do with subsequent inaccuracy meted out at the
hands of the lbs???



The way you say that, I become ever more certain that
you have no experience with high quality racing bicycle cotters, the
mainstream when I began bicycling over longer distances.

cotters were fundamentally misconceived. your defense of them is bizarre
given your favorite hobby-horse of pedal thread fretting, yet apparently
you're oblivious to the same effects in this application.





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.

We saw many of these from people like you who could not visualize how
great the forces are in this interface and that one crank puts the major
load on the narrow part of the cotter-flat while the other did so on the
widest part. You have your choice. My choice was to have the retaining
nut on the trailing face of the crank at the top of the stroke.

yeah. trouble is though jobst, the greatest area of contact ran the other
way...




We don't (didn't?) want a "small" amount of pin/spindle[/crank]
contact. We want (wanted?) ~full~, tight contact all along the length
of the pin. That calls for proper fitting, not cheap-assed
swage-fitting where the pin is fat in one localized spot, and loose (or
loosening) everywhere else.

Well you can't do that anyway, because that would not leave cranks 180°
apart as they should be.

eh??? all you need is to have the pins finished the same and oriented
correctly - this is not rocket science.



And the only reason to "lubricate" cotter pins (w/ appropriate grease)
is to be able to easily pop them out in order to service the BB. They
don't fail from inadequate greasing.

Might bend the threaded section when driving them out, but that goes
with the territory. And there's an acquirable "touch" for avoiding
that. Well, it's mostly luck.

That's the classic demise of cotters. That is why one doesn't extract
them without a pair of new ones in the event of a squashed thread.

you got that bit right at least. ridiculous design.

"jim beam" wrote:
On Sun, 28 Dec 2008 03:29:26 +0000, jobst.brandt wrote:

[...]
The way you say that, I become ever more certain that
you have no experience with high quality racing bicycle cotters, the
mainstream when I began bicycling over longer distances.

cotters were fundamentally misconceived. your defense of them is bizarre
given your favorite hobby-horse of pedal thread fretting, yet apparently
you're oblivious to the same effects in this application.
[...]

Where did Jobst defend cotter cranks as being a good design? I missed
that. Please provide a citation.

Obviously, when Jobst took up serious cycling (late 1940's or early
1950's?), there were no quality alternatives to cottered cranks. From
Jobst's postings, it appears he abandoned cottered cranks shortly after
quality square taper cranks became available.

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

On Sat, 27 Dec 2008 21:55:04 -0600, Tom Sherman wrote:

"jim beam" wrote:
On Sun, 28 Dec 2008 03:29:26 +0000, jobst.brandt wrote:

[...]
The way you say that, I become ever more certain that you have no
experience with high quality racing bicycle cotters, the mainstream
when I began bicycling over longer distances.

cotters were fundamentally misconceived. your defense of them is
bizarre given your favorite hobby-horse of pedal thread fretting, yet
apparently you're oblivious to the same effects in this application.
[...]

Where did Jobst defend cotter cranks as being a good design? I missed
that. Please provide a citation.

serious social perception issue there tom! discuss that with your medical
professional.




Obviously, when Jobst took up serious cycling (late 1940's or early
1950's?), there were no quality alternatives to cottered cranks. From
Jobst's postings, it appears he abandoned cottered cranks shortly after
quality square taper cranks became available.

as did we all. stupid design.

In article ,
writes:
Tom Keats wrote:

The manufacturers of steel pinned cranks seem to feel a heavy cast ste=
el=20
press with 42:1 leverage driven forcefully ( an able man puts out abou=
t=20
80 pounds with both arms just below shoulder height) is a better=20
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.

For forcing barrel-chested or wrongly-sized cotter pins into
straight-tapered holes, I'm not surprised.

You are conjuring up unreal circumstances. The Best cotters were from
"Acier Dupratnik" and were of high strength steel. Just the same,
they were designed to be filed or machined to identical flats and they
could be pushed through the bare crank with little effort.

That's how it should be. Or should be rendered.

The press
fit comes when the spindle is in the crank and the cotter inserted to
arrest it in a rotationally fixed position that must be identical for
both cranks or sprinting would impractical.

I have enough hand-to-eye coordination and feel to do that.

But cotter pins are not barrel-chested. I actually have a few in my
stock -- I've slid dial calipers down them, and there's no widening
in their middles. Straight taper pins; straight taper holes. As it
should be, as long as there's a perfect fit with no slop.

It would be unimaginable that Acier Dupratnik would go to all the
trouble of machining these cotters from high grade steel bar stock
that wasn't straight. The way you say that, I become ever more
certain that you have no experience with high quality racing bicycle
cotters, the mainstream when I began bicycling over longer distances.

The way /you/ say it, you can't even get cotter pins in without
a fancy hydraulic press and a bunch of fussy alignment.

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.

We saw many of these from people like you who could not visualize how
great the forces are in this interface and that one crank puts the
major load on the narrow part of the cotter-flat while the other did
so on the widest part. You have your choice. My choice was to have
the retaining nut on the trailing face of the crank at the top of the
stroke.

I guess the nut is always on top of the cotter pin, and there's
nothing anyone can do about that.


We don't (didn't?) want a "small" amount of pin/spindle[/crank]
contact. We want (wanted?) ~full~, tight contact all along the
length of the pin. That calls for proper fitting, not cheap-assed
swage-fitting where the pin is fat in one localized spot, and loose
(or loosening) everywhere else.

Well you can't do that anyway, because that would not leave cranks
180=C2=B0 apart as they should be.

Oi, bloody hell! Please, not the Q-factor thing again!
How does how convexly tapered pegs in squarely tapered
holes fit, do with crank spacing anyways?

Sometimes metal components should have some leeway between
them. Other times, they shouldn't.

And the only reason to "lubricate" cotter pins (w/ appropriate
grease) is to be able to easily pop them out in order to service the
BB. They don't fail from inadequate greasing.

Might bend the threaded section when driving them out, but that goes
with the territory. And there's an acquirable "touch" for avoiding
that. Well, it's mostly luck.

That's the classic demise of cotters. That is why one doesn't extract
them without a pair of new ones in the event of a squashed thread.

Ones that actually & properly fit in the first place.


cheers,
Tom


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

"jim beam" wrote:
On Sat, 27 Dec 2008 21:55:04 -0600, Tom Sherman wrote:

"jim beam" wrote:
On Sun, 28 Dec 2008 03:29:26 +0000, jobst.brandt wrote:

[...]
The way you say that, I become ever more certain that you have no
experience with high quality racing bicycle cotters, the mainstream
when I began bicycling over longer distances.
cotters were fundamentally misconceived. your defense of them is
bizarre given your favorite hobby-horse of pedal thread fretting, yet
apparently you're oblivious to the same effects in this application.
[...]
Where did Jobst defend cotter cranks as being a good design? I missed
that. Please provide a citation.

serious social perception issue there tom! discuss that with your medical
professional.

So "jim beam" apparently can not provide a citation.



Obviously, when Jobst took up serious cycling (late 1940's or early
1950's?), there were no quality alternatives to cottered cranks. From
Jobst's postings, it appears he abandoned cottered cranks shortly after
quality square taper cranks became available.

as did we all. stupid design.

So "jim beam" criticizes Jobst for using the best commercially available
design at the time? Sheesh!

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

On Sat, 27 Dec 2008 22:02:08 -0600, Tom Sherman wrote:

"jim beam" wrote:
On Sat, 27 Dec 2008 21:55:04 -0600, Tom Sherman wrote:

"jim beam" wrote:
On Sun, 28 Dec 2008 03:29:26 +0000, jobst.brandt wrote:

[...]
The way you say that, I become ever more certain that you have no
experience with high quality racing bicycle cotters, the mainstream
when I began bicycling over longer distances.
cotters were fundamentally misconceived. your defense of them is
bizarre given your favorite hobby-horse of pedal thread fretting, yet
apparently you're oblivious to the same effects in this application.
[...]
Where did Jobst defend cotter cranks as being a good design? I missed
that. Please provide a citation.

serious social perception issue there tom! discuss that with your
medical professional.

So "jim beam" apparently can not provide a citation.

more perception problems! or your newsreader doesn't allow you to follow
a thread.






Obviously, when Jobst took up serious cycling (late 1940's or early
1950's?), there were no quality alternatives to cottered cranks. From
Jobst's postings, it appears he abandoned cottered cranks shortly
after quality square taper cranks became available.

as did we all. stupid design.

So "jim beam" criticizes Jobst for using the best commercially available
design at the time? Sheesh!

no, i'm criticizing defense of cotter pin use - jobst's position that
they're ok if "driven home hard enough". they're /never/ ok.

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

[...]
We don't (didn't?) want a "small" amount of pin/spindle[/crank]
contact. We want (wanted?) ~full~, tight contact all along the
length of the pin. That calls for proper fitting, not cheap-assed
swage-fitting where the pin is fat in one localized spot, and loose
(or loosening) everywhere else.
Well you can't do that anyway, because that would not leave cranks
180=C2=B0 apart as they should be.

Oi, bloody hell! Please, not the Q-factor thing again!
How does how convexly tapered pegs in squarely tapered
holes fit, do with crank spacing anyways?[...]

I think you misunderstand. The desired alignment is having the cranks be
180° apart in plan view, and has nothing to do with pedal tread width.

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

"jim beam" wrote:
On Sat, 27 Dec 2008 22:02:08 -0600, Tom Sherman wrote:

"jim beam" wrote:
On Sat, 27 Dec 2008 21:55:04 -0600, Tom Sherman wrote:

"jim beam" wrote:
On Sun, 28 Dec 2008 03:29:26 +0000, jobst.brandt wrote:

[...]
The way you say that, I become ever more certain that you have no
experience with high quality racing bicycle cotters, the mainstream
when I began bicycling over longer distances.
cotters were fundamentally misconceived. your defense of them is
bizarre given your favorite hobby-horse of pedal thread fretting, yet
apparently you're oblivious to the same effects in this application.
[...]
Where did Jobst defend cotter cranks as being a good design? I missed
that. Please provide a citation.
serious social perception issue there tom! discuss that with your
medical professional.

So "jim beam" apparently can not provide a citation.

more perception problems! or your newsreader doesn't allow you to follow
a thread.

So "jim beam" apparently can not provide a citation. Enough said.

Obviously, when Jobst took up serious cycling (late 1940's or early
1950's?), there were no quality alternatives to cottered cranks. From
Jobst's postings, it appears he abandoned cottered cranks shortly
after quality square taper cranks became available.
as did we all. stupid design.

So "jim beam" criticizes Jobst for using the best commercially available
design at the time? Sheesh!

no, i'm criticizing defense of cotter pin use - jobst's position that
they're ok if "driven home hard enough". they're /never/ ok.

No "jim", Jobst was writing in the context of what was best if cotters
were being used. Of course, your personal hatred of Jobst blinds you to
reason when reading his posts.

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

Tom Keats wrote:

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

You keep trying to convince those of us who worked with these devices
that you don't know anything about it or you wouldn't dismiss the tool
used to install cotters. They cannot be installed by hand.

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.

For forcing barrel-chested or wrongly-sized cotter pins into
straight-tapered holes, I'm not surprised.

You are conjuring up unreal circumstances. The Best cotters were
from "Acier Dupratnik" and were of high strength steel. Just the
same, they were designed to be filed or machined to identical flats
and they could be pushed through the bare crank with little effort.

That's how it should be. Or should be rendered.

What do you mean by "should be rendered"?

The press fit comes when the spindle is in the crank and the cotter
inserted to arrest it in a rotationally fixed position that must be
identical for both cranks or sprinting would impractical.

I have enough hand-to-eye coordination and feel to do that.

This requires fixturing to do this correctly and in the web page from
Shelton's site, you see such a fixture. I made my own and have
forgotten what the angle was but is was far less than what was
commonly used, that giving a larger surface for the narrow end of the
elliptical flat face.

But cotter pins are not barrel-chested. I actually have a few in
my stock -- I've slid dial calipers down them, and there's no
widening in their middles. Straight taper pins; straight taper
holes. As it should be, as long as there's a perfect fit with no
slop.

It would be unimaginable that Acier Dupratnik would go to all the
trouble of machining these cotters from high grade steel bar stock
that wasn't straight. The way you say that, I become ever more
certain that you have no experience with high quality racing
bicycle cotters, the mainstream when I began bicycling over longer
distances.

The way /you/ say it, you can't even get cotter pins in without
a fancy hydraulic press and a bunch of fussy alignment.

That's true, but as I mentioned, the press fit is preload on the
spindle, just as one needs preload on a square taper aluminum crank.
This is not because the cotter doesn't fit, but because it needs high
preload to no fret in use.

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.

We saw many of these from people like you who could not visualize
how great the forces are in this interface and that one crank puts
the major load on the narrow part of the cotter-flat while the
other did so on the widest part. You have your choice. My choice
was to have the retaining nut on the trailing face of the crank at
the top of the stroke.

I guess the nut is always on top of the cotter pin, and there's
nothing anyone can do about that.

As I said, don't dig yourself in deeper. Cotters are mirror image
installation and if one goes from top to bottom with the crank extended
froward, the other crank will go from top to bottom with the crank
rearward. Maybe Andrew has a photo of this to make it clear.

We don't (didn't?) want a "small" amount of pin/spindle[/crank]
contact. We want (wanted?) ~full~, tight contact all along the
length of the pin. That calls for proper fitting, not cheap-assed
swage-fitting where the pin is fat in one localized spot, and
loose (or loosening) everywhere else.

Well you can't do that anyway, because that would not leave cranks
180° apart as they should be.

Oi, bloody hell! Please, not the Q-factor thing again! How does
how convexly tapered pegs in squarely tapered holes fit, do with
crank spacing anyways?

Cotters are cylindrical and have a sloping face toward the spindle.
You are imagining this assembly incorrectly.

Sometimes metal components should have some leeway between them.
Other times, they shouldn't.

What do you mean by that?

And the only reason to "lubricate" cotter pins (w/ appropriate
grease) is to be able to easily pop them out in order to service
the BB. They don't fail from inadequate greasing.

Might bend the threaded section when driving them out, but that
goes with the territory. And there's an acquirable "touch" for
avoiding that. Well, it's mostly luck.

That's the classic demise of cotters. That is why one doesn't
extract them without a pair of new ones in the event of a squashed
thread.

Ones that actually & properly fit in the first place.

I don't think you understand press fits, especially in this context.
You say all this and have no idea how to install cottered cranks.
Please don't confuse those who might consider overhauling an antique
with such steel cranks.

Nothing is safe from me.

That is not hard to believe.

I'm really at:
tkeats curlicue vcn dot bc dot ca


Jobst Brandt

On Sat, 27 Dec 2008 22:21:16 -0600, Tom Sherman wrote:

"jim beam" wrote:
On Sat, 27 Dec 2008 22:02:08 -0600, Tom Sherman wrote:

"jim beam" wrote:
On Sat, 27 Dec 2008 21:55:04 -0600, Tom Sherman wrote:

"jim beam" wrote:
On Sun, 28 Dec 2008 03:29:26 +0000, jobst.brandt wrote:

[...]
The way you say that, I become ever more certain that you have no
experience with high quality racing bicycle cotters, the
mainstream when I began bicycling over longer distances.
cotters were fundamentally misconceived. your defense of them is
bizarre given your favorite hobby-horse of pedal thread fretting,
yet apparently you're oblivious to the same effects in this
application. [...]
Where did Jobst defend cotter cranks as being a good design? I
missed that. Please provide a citation.
serious social perception issue there tom! discuss that with your
medical professional.

So "jim beam" apparently can not provide a citation.

more perception problems! or your newsreader doesn't allow you to
follow a thread.

So "jim beam" apparently can not provide a citation. Enough said.

mea culpa - i can't be bothered to do your rudimentary google searching
for you.




Obviously, when Jobst took up serious cycling (late 1940's or early
1950's?), there were no quality alternatives to cottered cranks.
From Jobst's postings, it appears he abandoned cottered cranks
shortly after quality square taper cranks became available.
as did we all. stupid design.

So "jim beam" criticizes Jobst for using the best commercially
available design at the time? Sheesh!

no, i'm criticizing defense of cotter pin use - jobst's position that
they're ok if "driven home hard enough". they're /never/ ok.

No "jim", Jobst was writing in the context of what was best if cotters
were being used. Of course, your personal hatred of Jobst blinds you to
reason when reading his posts.

don't read closely enough - do you.