Re: I fixed a broken spoke!

Quoted message said:

Ben C? writes:

[snip]

Quoted message said:

Quoted message said:

OK shall we call it "tension induced stress"? That sounds good to

me.

Not really, "residual stress" is not "tension induced stress", it is
just the opposite. It is residual stress caused by changing the shape
of the spoke elbow from an obtuse to acute angle, the principal
operator in this discussion.

OK I'm reverting to "elbow bend stress" then.

[snip]

Quoted message said:

Quoted message said:

How much tension would you need in the spoke to hold the elbow at
yield with the spoke flush to the flange?

None. It is at yield already. Any additional tension only stretches
the spoke at that stress, it being as high as it can be. From what
you write, it seems you think yield is a passing condition that must
be maintained by continuing increase in tension.

Not an increase, but it must be maintained by tension, yes.

Quoted message said:

If you put a spoke in a vise and bend it until the free end is
touching the top of the jaw (~90°) it is at yield and if you don't let
go, it remains at that stress just as the spoke in the flange does.

Yes but if you "don't let it go" you are maintaining the tension. If you
push down on the spoke you can maintain yield stress at the elbow with
relatively low applied force since the moment is big.

But suppose you keep the free end flush with the top of the jaw _only by
pulling it along its length_. How much force would that take?

Quoted message said:

Quoted message said:

I contend that it is a lot, much more than you've got.

I see that there is a major difference in visualizing what yield
stress is between what you propose and what I understand about this.
I work around mechanical and materials engineers who have no
difficulty in understanding and agreeing with what I have been writing
in this thread and I assumed that if I stated it in detail that it
should make sense to you.

Yes, and we got there in the end, and I thank you for your persistence.
I do understand it, but I don't agree with it.

My visualization requires nothing more than simple geometry, and the
stress/strain graph for stainless steel provided and explained by jim
beam. You should have no difficulty understanding it. The place to start
that I would recommend is as I keep asking you, to consider how the
force required to keep a bend at yield varies with the direction in
which that force is applied.

Maybe you're right that's immaterial, but if you want to understand my
visualization, that's the place the start.

And my visualization may be wrong, but you need to understand it if
you want to tell me where and how.

Quoted message said:

Quoted message said:

Therefore the yield stress must have gone somewhere. The
explanation of moments and hub-hole deformation that I've given in
several recent posts is a coherent hypothesis, as far as I know, but
I am interested in cogent counter-arguments.

The problem with that is that the spoke would have to open its elbow
bend to adjust to a deeper yielding of the flange hole. Two things
speak against that, the first being that the elbow would not have an
acute angel

No, in my version it would still have an acute angle, just not _as_
acute as if the hub hole didn't deform at all.

Quoted message said:

and that the spoke head rests firmly against the other
side of the flange so that it doesn't open to a large obtuse angle as
some pictures have shown.

I'm OK with the spoke head resting firmly on the other side of the
flange. The path the shank takes through the hub is what changes.

Quoted message said:

I think this is all related to resistance to various aspects of
mechanical stress relief.

I accept mechanical stress relief as described by you as a premise.

[snip]

Quoted message said:

Quoted message said:

Quoted message said:

> I have tried my best. I invite you to explain in your own terms
> how to work out how much force is required to yield the elbow of a
> spoke flush to the flange by pulling on its axis.

Quoted message said:

Quoted message said:

That is immaterial.

Quoted message said:

I'm still interested to know, even if it is immaterial.

Lack of a definition of where the force should be measured, I'll say
roughly a push with my thumb.

No, I said "pulling on its axis". Pushing with the thumb is in a
different direction and provides a much higher moment.

Quoted message said:

Bending in these terms does not take much force because the stress is
confined to such a small cross section and bedding produces large
loads in a slender cross section.

You've lost me here. The spoke is the same cross-section. The difference
is moment.

Quoted message said:

Folding a sheet of aluminum foil back on itself is trivial while doing
that with 1mm thick aluminum sheet is strikingly greater.

Yes but we only have one spoke and it's all about the same thickness
(except for butting...)

[snip]

Quoted message said:

Quoted message said:

Yes really! I am interested in these matters, and you are a good
source of knowledge about them. Why else am I reading r.b.t?

I'm never sure. I've been strung along in such exchanges that ended
with participants finally revealing their purpose, which was to
discredit my book on the subject, while exiting in rude, door slamming
manner. Most of these have come from GB for some reason.

I do not want to discredit you or your book. I do not start out wanting
to disagree with you or "prove you wrong". I just have a curiosity how
these things work, that is all.

With your help and that of others, including jim beam, I'm learning a
lot here, so many thanks.

I admit I am from GB.

Tim McNamara said:

In article <[email hidden]>,

Ben C said:

The key premises here are:

1. Normal spoke tension is much lower than the amount required to yield
a spoke axially.

The spoke tension is not applied completely axially- part of the spoke
is bent at about 100 degrees. The bend of the elbow does not have
tension applied to it axially as the elbow is a curve of a small radius.
Does that make a difference?

Probably, but only a small one. I still think the tension required to
keep that bend in place will be near the amount required to stretch the
wire axially.

The situation is similar to pulling a kink out of a straight wire. The
straighter the kink gets the smaller the moment and the higher the force
required until ultimately you're at the point of stretching the wire
itself.

Quoted message said:

It's easy to make the spoke yield the normal to the axis- it can be done
with finger pressure. Normal spoke tension clearly exceeds the elastic
limit of the steel used in spokes as the spokes take a visually
identifiable set and can be identified as head-in or head-out spokes
after removal from the wheel.

That might have been got there when the spoke line was corrected with a
thumb etc.

jim beam did post the picture of those spokes that were hardly deformed
at all at the elbow.

I suspect you get a bit of both (elbow bending and hub deformation)
depending on choice of components and build process. jim beam does not
advocate early spoke line correction, and with whatever hubs and spokes
he was using, he got the results we saw, which were quite surprising,
because often you do see more of a set. The point is, it varies.

As you say, you don't need much thumb pressure to bend a spoke, but
that's because you've got leverage-- a moment-- the stress where the
spoke's bending is much higher.

If you pull the spoke along its axis you need quite a bit more force to
bend the elbow. If the elbow angle is too wide, though, I think there's
likely to be enough of a moment for that to happen. But as it gets close
to flush with the flange, the force required gets much higher.

That's the theory anyway.

Quoted message said:

Quoted message said:

2. If the spoke is flush with the flange, the spoke tension that would
be required to keep the elbow at yield be very nearly as high as that
required to yield the spoke axially.

Except that the elbow is not loaded axially, as far as I can tell from
looking at spokes in a hub. It's more like a shear.

I agree. But I think the force required is close to the amount you would
need to yield it axially, that's all.

Quoted message said:

Quoted message said:

Therefore normal spoke tension cannot keep the elbow bend at yield. The
hub hole deformation mechanism described above explains where that yield
stress went.

Inspecting my used unlaced hubs, the only deformation I see is a tiny
dent from the contact of the inside of the elbow that is at best a few
thousandths of an inch deep. The spoke flange is much thicker than a
spoke and is countersunk as well to provide a socket for the head to fit
into.

Interesting. I've got a couple of used unlaced hubs which I shall also
have a look at.

I also think that manual spoke line correction with a thumb at quite low
tension may be able to bend the elbow further than one thinks, depending
on how the spoke's sitting in the hole. If it's tilting a bit, you can
put the bend in it, then tilt it back.

Hard to describe, but just think of it practically. Suppose you threaded
a spoke through a hub and didn't attach it to the rim. The challenge is
to bend the elbow so that when the head is seated properly, the spoke
lies flush with the flange. I think that could probably be achieved with
a bit of wobbling and bending.

I know noone corrects the spoke line with the spoke unattached to the
rim, but you've got that kind of arc up towards the crossing, and I'm
not sure if the head isn't tilted back a bit at that point. I shall go
and try this later. I may be talking complete rubbish.

Ben C said:

Peter Cole said:

Ben C said:

On 2007-01-08, Peter Cole <[email hidden]> wrote:
> If you were to say that the spoke bent first, then unbent as the hub
> deformed, then I could understand (although not necessarily agree with)
> your description

[snip]

Quoted message said:

Quoted message said:

But I think there are some situations in which the elbow bends, then the
hub yields, unbending the elbow.

I think the elbow must unbend in all cases where we end up with the
spoke flush to the flange

OK, I think I've reached an understanding of your hypothesis.

If we assume that the spoke starts out with an obtuse angle (95 deg.
nom.), and that the load path is acute, and the hub does not deform,
then I guess we'd agree that the spoke would bend during tensioning and
remain at yield?

Yes.

Quoted message said:

If we kept those assumptions, but added that the hub hole had been
pre-deformed (before tensioning -- as in reusing a hub) would you agree
that the same condition would be reached?

Good question. I don't think we would reach the same condition. There
are two possibilities: either the hub deforms further, or if it is
somehow hardened up by having been deformed the first time, the spoke
does not become flush and "tension induced stress"[1] remains.

OK, your "#2" would mean reaching the same condition, so you're saying
you think "#1" happens, namely the hub deforms further.

I don't think this is likely, because the thing that stops hub
deformation is the equilibrium that is reached by the "contact patch"
area getting large enough that the stress (force/area) becomes too small
for additional plastic deformation. The deformation geometry is such
that the contact area grows non-linearly with deformation, so it grows
fast then reaches near equilibrium early (in the tensioning), I can see
no mechanism for further growth -- say if you were to bring to full
tension, relax, then bring to full tension again. I don't think
hardening is necessary to explain this.

Quoted message said:

If the first possibility is true, you could extrapolate and say if I
reuse the same hub too many times, won't the spokes cut right through
it? Well, no, it will just approach a perfect 95 degree hole.

Two things, first I question the assumption that 95 degrees is
"perfect", second, that the angular mismatch is the thing that is
driving hub hole deformation. A cantilever load has both a bending force
and a shear force, when the effective beam length goes to 0, you still
have the shear (unchanged).

Quoted message said:

Quoted message said:

If you agree to the above, the only other variable is the contribution
of hub deformation during tensioning. If most of the hub deformation
happens as the hub is brought to initial tension, and the spoke still
does not lie flat to the flange, it can only mean that the spoke path
and load path are not aligned and the spoke must still be under bending
stress.

I do agree pretty much with this: if spoke path and load path are not
aligned then there is some bending stress. But it may be well below
yield. Any value between 0 and yield is possible depending on how much
hub hole deformed.

Perhaps we need to agree on the meaning of "yield" in this context. If
we assume that the load path angle and spoke angle are sufficiently
mismatched (even with hole deformation) that the spoke angle becomes
permanently altered (bent to a smaller angle), then we have yielded the
"bulk" -- plastic yield has penetrated far enough beneath the skin so
that the spoke can't just relax back to its initial shape. Your
hypothesis is that the spoke may well reach that point then partially
relax as the hub hole continues to deform. You assume that this will
bring the material below "yield", but "yield" isn't a firm threshold,
there is a plastic region, both in the stress/strain curve and
physically in the spoke cross section.

If we look at this problem as a "beam" problem, we see that we have 2
forces creating hub hole deformation -- bending force and shear force.
Shear is directly proportional to load (spoke tension), and bending
force is proportional to the load times the beam length. When we first
start applying tension, the effective beam length makes the bending
force dominate hole deformation. As we continue to increase tension, the
effective beam length decreases, but only because the spoke is bending
further, which means that the bending force must be increasing. At each
point of increased tension, a new equilibrium is reached on the contact
area of the spoke and hub where the area has become large enough
(through deformation) to reduce the stress (force/area) to below yield.
As long as the bending force is dominating hole deformation, increase in
deformation must be accompanied by (driven by) increasing bending force,
which means the bending stress in the spoke is continuing to rise. For
deformation to continue to increase accompanied by a drop in bending
force, shear force must be dominating.

Your hypothesis depends on shear force alone driving additional
(significant) hole deformation, causing, in turn, a drop in bending
force. I find this unlikely since deformation will have reached a point
of diminishing returns early in this process (of tensioning).

Quoted message said:

Quoted message said:

If we flatten (thumb, etc.) the spoke at that time, we will have
lowered the bending stress (by forcing yield), but we can't make it
perfect since we can't bend the spoke perfectly flat, so there will
always be some bending stress left.

Yes, but also if thumb the spoke then it won't get flush to the flange
(because of spring-back).

We'd need to bend it a bit past flush and let it jump back a bit.

Which we can't do if we're "correcting" a tensioned spoke.

Quoted message said:

Actually I think that might be possible if we thumb the spoke earlier in
the build, because the head will not necessarily be completely flush in
its hole when there's not much tension. So you might be able to sort of
hinge the spoke back, bend it, and swing it back into place.

Of course it is possible to "over correct" before the spoke is
tensioned, but that's a different scenario.

Quoted message said:

My differences from Jobst are that I think you will have
some remaining tension induced stress between 0 or almost 0 and yield
depending on the difference between load path angle and spoke angle.
Jobst says the angles are the same (i.e. spoke flush to flange) and that the
remaining tension induced stress is therefore "close to yield".

I think "your differences with Jobst" require that the spoke hole is
deformed significantly late in the tensioning by shear forces alone --
something that is very unlikely.

In article <[email hidden]>,

Ben C said:

Tim McNamara said:

In article <[email hidden]>,

Ben C said:

The key premises here are:

1. Normal spoke tension is much lower than the amount required to
yield
a spoke axially.

The spoke tension is not applied completely axially- part of the
spoke is bent at about 100 degrees. The bend of the elbow does not
have tension applied to it axially as the elbow is a curve of a
small radius. Does that make a difference?

Probably, but only a small one. I still think the tension required to
keep that bend in place will be near the amount required to stretch
the wire axially.

The situation is similar to pulling a kink out of a straight wire.
The straighter the kink gets the smaller the moment and the higher
the force required until ultimately you're at the point of stretching
the wire itself.

Except that the hub flange prevents the kink from being pulled out

Quoted message said:

Quoted message said:

It's easy to make the spoke yield the normal to the axis- it can be
done with finger pressure. Normal spoke tension clearly exceeds
the elastic limit of the steel used in spokes as the spokes take a
visually identifiable set and can be identified as head-in or
head-out spokes after removal from the wheel.

That might have been got there when the spoke line was corrected with
a thumb etc.

It also happens on machine built wheels where no such process happens.

Quoted message said:

jim beam did post the picture of those spokes that were hardly
deformed at all at the elbow.

I suspect you get a bit of both (elbow bending and hub deformation)
depending on choice of components and build process. jim beam does
not advocate early spoke line correction, and with whatever hubs and
spokes he was using, he got the results we saw, which were quite
surprising, because often you do see more of a set. The point is, it
varies.

As you say, you don't need much thumb pressure to bend a spoke, but
that's because you've got leverage-- a moment-- the stress where the
spoke's bending is much higher.

If you pull the spoke along its axis you need quite a bit more force
to bend the elbow. If the elbow angle is too wide, though, I think
there's likely to be enough of a moment for that to happen. But as it
gets close to flush with the flange, the force required gets much
higher.

That's the theory anyway.

It seems to me that the constraints of the hub holding the spoke would
result in the force of the tension being concentrated in a fairly small
region of the bend, which should coincide with the highest point of
residual stress on the outside of the spoke elbow. I don't know that's
correct; I am constructing a diagram in my head to consider this.

Quoted message said:

Quoted message said:

Quoted message said:

2. If the spoke is flush with the flange, the spoke tension that
would
be required to keep the elbow at yield be very nearly as high
as that required to yield the spoke axially.

Except that the elbow is not loaded axially, as far as I can tell
from looking at spokes in a hub. It's more like a shear.

I agree. But I think the force required is close to the amount you
would need to yield it axially, that's all.

Just from looking at the shapes of the spoke and the hub, I don't agree.
The force would approach the axial yield strength at the end of the
elbow nearest the straight section of the spoke, but would be lower as
the angle of the spoke changes towards normal to the axis. And the
moment of the outside of the spoke elbow would be greater than that of
the inside of the elbow.

Quoted message said:

Quoted message said:

Quoted message said:

Therefore normal spoke tension cannot keep the elbow bend at
yield. The hub hole deformation mechanism described above explains
where that yield stress went.

Inspecting my used unlaced hubs, the only deformation I see is a
tiny dent from the contact of the inside of the elbow that is at
best a few thousandths of an inch deep. The spoke flange is much
thicker than a spoke and is countersunk as well to provide a socket
for the head to fit into.

Interesting. I've got a couple of used unlaced hubs which I shall
also have a look at.

I also think that manual spoke line correction with a thumb at quite
low tension may be able to bend the elbow further than one thinks,
depending on how the spoke's sitting in the hole. If it's tilting a
bit, you can put the bend in it, then tilt it back.

I would agree that one can bend the spoke quite a bit with one's thumb.

Quoted message said:

Hard to describe, but just think of it practically. Suppose you
threaded a spoke through a hub and didn't attach it to the rim. The
challenge is to bend the elbow so that when the head is seated
properly, the spoke lies flush with the flange. I think that could
probably be achieved with a bit of wobbling and bending.

I tap the spokes down onto the hub flange with a small dead blow hammer
head (no handle). That seems to get the spoke to lie flat along the
flange quite easily. However this still does not result in a perfectly
straight line to the spoke hole in the rim for the heads-in spokes with
most hubs I have used. There is still a bit of curvature between the
spoke flange and the interweaved spoke crossing.

Quoted message said:

I know noone corrects the spoke line with the spoke unattached to the
rim, but you've got that kind of arc up towards the crossing, and I'm
not sure if the head isn't tilted back a bit at that point. I shall
go and try this later. I may be talking complete rubbish.

Tim McNamara said:

In article <[email hidden]>,
Ben C <[email hidden]> wrote:

[snip]

Quoted message said:

Quoted message said:

Quoted message said:

It's easy to make the spoke yield the normal to the axis- it can be
done with finger pressure. Normal spoke tension clearly exceeds
the elastic limit of the steel used in spokes as the spokes take a
visually identifiable set and can be identified as head-in or
head-out spokes after removal from the wheel.

That might have been got there when the spoke line was corrected with
a thumb etc.

It also happens on machine built wheels where no such process happens.

Yes, as I said I think it also can occur from spoke tension alone.

[snip]

Quoted message said:

Quoted message said:

I agree. But I think the force required is close to the amount you
would need to yield it axially, that's all.

Just from looking at the shapes of the spoke and the hub, I don't agree.
The force would approach the axial yield strength at the end of the
elbow nearest the straight section of the spoke, but would be lower as
the angle of the spoke changes towards normal to the axis. And the
moment of the outside of the spoke elbow would be greater than that of
the inside of the elbow.

Yes, I think that's probably about right. But the difference in moment
is only somewhere around the width of a spoke.

Ben C said:

My main difference with Jobst is that I cannot see how it is possible
for the elbow to be held at yield by spoke tension with a spoke flush to
the flange.

Jobst says it must be there because there is nowhere for it to have
gone. I say but there's no way it can be there, so it must have gone
somewhere.

Jobst is saying that the spoke remains (as it must) on a stress/strain
curve. There can be no change in stress without a corresponding change
in strain. If the spoke bends as it is tensioned, the bending stress
increases. For it to decrease, the spoke must unbend. Bending force
can't unbend a spoke, so the only other candidate is shear force, acting
through additional hole deformation, which is unlikely for a number of
(previously given) reasons.

Quoted message said:

The hypothesis about hub-hole deformation is to explain where it went.

You claim to only request an explanation, but you're actually proposing
a hypothesis. I don't mean to sound snotty, but given your background,
doesn't that strike you as a bit of a reach?

Peter Cole said:

Ben C said:

My main difference with Jobst is that I cannot see how it is possible
for the elbow to be held at yield by spoke tension with a spoke flush to
the flange.

Jobst says it must be there because there is nowhere for it to have
gone. I say but there's no way it can be there, so it must have gone
somewhere.

Jobst is saying that the spoke remains (as it must) on a stress/strain
curve. There can be no change in stress without a corresponding change
in strain.

Yes, I think this much is well-known.

Quoted message said:

If the spoke bends as it is tensioned, the bending stress increases.
For it to decrease, the spoke must unbend. Bending force can't unbend
a spoke, so the only other candidate is shear force, acting through
additional hole deformation, which is unlikely for a number of
(previously given) reasons.

Quoted message said:

Quoted message said:

The hypothesis about hub-hole deformation is to explain where it went.

You claim to only request an explanation, but you're actually proposing
a hypothesis.

I'd like both. An explanation, and to propose a hypothesis. I do not
consider the activities to be widely different.

Forming and testing hypotheses is all about trying to understand things.
Isn't that what we're doing? Or are we just expected to take on faith
everything that is told to us?

Rather than persistently demanding an explanation, a better way to move
things forward is often to propose one yourself and discuss that
instead.

Quoted message said:

I don't mean to sound snotty, but given your background, doesn't that
strike you as a bit of a reach?

No, what's wrong with it? It's interesting to me and perhaps others to
hear comments on a hypothesis, although I can understand if people might
be rather bored of the topic by now.

If you don't want to comment then you don't have to. I will say though
that your comments have been interesting.

Ben C said:

Peter Cole said:

Ben C said:

My main difference with Jobst is that I cannot see how it is possible
for the elbow to be held at yield by spoke tension with a spoke flush to
the flange.

Jobst says it must be there because there is nowhere for it to have
gone. I say but there's no way it can be there, so it must have gone
somewhere.

Jobst is saying that the spoke remains (as it must) on a stress/strain
curve. There can be no change in stress without a corresponding change
in strain.

Yes, I think this much is well-known.

Quoted message said:

If the spoke bends as it is tensioned, the bending stress increases.
For it to decrease, the spoke must unbend. Bending force can't unbend
a spoke, so the only other candidate is shear force, acting through
additional hole deformation, which is unlikely for a number of
(previously given) reasons.

Quoted message said:

Quoted message said:

The hypothesis about hub-hole deformation is to explain where it went.

You claim to only request an explanation, but you're actually proposing
a hypothesis.

I'd like both. An explanation, and to propose a hypothesis. I do not
consider the activities to be widely different.

Forming and testing hypotheses is all about trying to understand things.
Isn't that what we're doing? Or are we just expected to take on faith
everything that is told to us?

Rather than persistently demanding an explanation, a better way to move
things forward is often to propose one yourself and discuss that
instead.

Quoted message said:

I don't mean to sound snotty, but given your background, doesn't that
strike you as a bit of a reach?

No, what's wrong with it? It's interesting to me and perhaps others to
hear comments on a hypothesis, although I can understand if people might
be rather bored of the topic by now.

If you don't want to comment then you don't have to. I will say though
that your comments have been interesting.

Dear Ben,

I'm hoping that you'll start a new thread ("What happens where the
spoke elbow meets the hub flange?" or some such title), explaining
that this ~500-post thread has sprawled so much that it's hard to
follow.

The new thread might begin with a summary of what you've been
discussing, suitable for the meanest intelligences, at least one of
which is not bored, but not too sure he's always following the main
point.

Cheers,

Carl Fogel

Ben C? writes:

[snip]

Quoted message said:

What exactly happens all comes down to small distances and angles
and is really quite subtle.

Quoted message said:

I also recall "flush to the flange" was given earlier as evidence
that there was no springback from thumb deformation, therefore the
elbow must remain at yield. If the spoke is not quite flush,
perhaps there was some springback...

There is always springback and only when spoke tension is increased
does the manual bend return practically to its closest position to the
flange. Stress relieving makes that even closer because the outside
of the bend yields at that time.

Quoted message said:

But don't answer these points here. Well you can if you want
obviously, but I will start a new thread with a summary of this as
Carl has just suggested.

Carl is at work!

Jobst Brandt

Quoted message said:

Ben C? writes:

[snip]

Quoted message said:

What exactly happens all comes down to small distances and angles
and is really quite subtle.

Quoted message said:

I also recall "flush to the flange" was given earlier as evidence
that there was no springback from thumb deformation, therefore the
elbow must remain at yield. If the spoke is not quite flush,
perhaps there was some springback...

There is always springback and only when spoke tension is increased
does the manual bend return practically to its closest position to the
flange. Stress relieving makes that even closer because the outside
of the bend yields at that time.

Quoted message said:

But don't answer these points here. Well you can if you want
obviously, but I will start a new thread with a summary of this as
Carl has just suggested.

Carl is at work!

Jobst Brandt

Dear Jobst,

No, Carl worked last night, something that he avoids as much as
possible.

Right now, Carl is eyeing the thermometer and trying to convince
himself that a sunny 37F must be significantly warmer than a cloudy
37F (sometimes it helps to be an English major).

If Carl fails to trick himself into testing the windchill, Carl's
fallback plan is to take his dog for a stroll along the bluffs and see
if the foxes that sneak along the face of the bluffs are willing to be
photographed. For several weeks, the probability of seeing the foxes
has been inversely proportional to whether Carl remembers to take his
camera.

Carl is not from GB, but he's convinced that the spokes do whatever
they do regardless of our red herrings. Carl wishes that he knew what
the spokes do, but will settle for Ben trying to summarize his theory
about flanges and shear and elbows trying to pull around corners in
terms that even Carl can follow.

Cheers,

Carl Fogel

Quoted message said:

Ben C? writes:

[snip]

Quoted message said:

What exactly happens all comes down to small distances and angles
and is really quite subtle.

Quoted message said:

I also recall "flush to the flange" was given earlier as evidence
that there was no springback from thumb deformation, therefore the
elbow must remain at yield. If the spoke is not quite flush,
perhaps there was some springback...

There is always springback and only when spoke tension is increased
does the manual bend return practically to its closest position to the
flange.

Makes sense. Anyway I will save this for the new thread.

Ben C said:

On 2007-01-09, Peter Cole <[email hidden]> wrote:

Quoted message said:

Forming and testing hypotheses is all about trying to understand things.
Isn't that what we're doing? Or are we just expected to take on faith
everything that is told to us?

Not faith, science, hopefully.

Quoted message said:

Rather than persistently demanding an explanation, a better way to move
things forward is often to propose one yourself and discuss that
instead.

Quoted message said:

I don't mean to sound snotty, but given your background, doesn't that
strike you as a bit of a reach?

No, what's wrong with it? It's interesting to me and perhaps others to
hear comments on a hypothesis, although I can understand if people might
be rather bored of the topic by now.

You're right, that was a snotty thing to say, even with a disclaimer, my
apologies.

Quoted message said:

If you don't want to comment then you don't have to. I will say though
that your comments have been interesting.

Thanks, it's always interesting to think about these things, even if the
discussions get a bit flame-y at times.

On 2007-01-09, Peter Cole <[email hidden]> wrote:
[snip]

Quoted message said:

Quoted message said:

If you don't want to comment then you don't have to. I will say though
that your comments have been interesting.

Thanks, it's always interesting to think about these things, even if the
discussions get a bit flame-y at times.

Well it feels like some stress has been relieved.

Carl has given me an essay to write now.

Quoted message said:

Quoted message said:

Ben C? writes:

[snip]

Quoted message said:

What exactly happens all comes down to small distances and angles
and is really quite subtle.

Quoted message said:

I also recall "flush to the flange" was given earlier as evidence
that there was no springback from thumb deformation, therefore the
elbow must remain at yield. If the spoke is not quite flush,
perhaps there was some springback...

There is always springback and only when spoke tension is increased
does the manual bend return practically to its closest position to the
flange. Stress relieving makes that even closer because the outside
of the bend yields at that time.

Quoted message said:

But don't answer these points here. Well you can if you want
obviously, but I will start a new thread with a summary of this as
Carl has just suggested.

Carl is at work!

Jobst Brandt

Dear Jobst,

No, Carl worked last night, something that he avoids as much as
possible.

Right now, Carl is eyeing the thermometer and trying to convince
himself that a sunny 37F must be significantly warmer than a cloudy
37F (sometimes it helps to be an English major).

If Carl fails to trick himself into testing the windchill, Carl's
fallback plan is to take his dog for a stroll along the bluffs and see
if the foxes that sneak along the face of the bluffs are willing to be
photographed. For several weeks, the probability of seeing the foxes
has been inversely proportional to whether Carl remembers to take his
camera.

Carl is not from GB, but he's convinced that the spokes do whatever
they do regardless of our red herrings. Carl wishes that he knew what
the spokes do, but will settle for Ben trying to summarize his theory
about flanges and shear and elbows trying to pull around corners in
terms that even Carl can follow.

Cheers,

Carl Fogel

I went riding and looked for foxes afterward. It warmed up to 41
degrees, but no foxes were promenading along the bluffs.

The next day, it hit 65 degrees, so I went riding in my shorts and then
tried to spot foxes again, without any luck.

Yesterday, Il waited an hour too long, but luckily wore my long tights
and jersey, even though it was 63 degrees. Heading out, I dropped three
gears to pedal into a beastly Chinook headwind.

While I was detouring down to the foot of the dam and back up to where
I turn around at the top of the ridge west of town, the wind changed
180 degrees and blew hard enough that I had to pedal back downhill. The
temperature dropped to 43 degrees. After trudging into a bad headwind
both ways, my third fox expedition proved fruitless.

Today, it's about 11 degrees and cloudy with a half-inch of new snow.
No bike ride, but lots of fox tracks along the bluffs. And a fox:

http://i3.tinypic.com/2lt0ahs.jpg

Click on the lower right in Explorer for a larger view. They look a lot
bigger when I surprise them while they're crossing the road down to the
river. They can easily avoid being seen by slow, noisy cars, but not a
bicycle coming around the bend at 35 mph.

CF

[email hidden] wrote:

[...deleted....]

Quoted message said:

...
180 degrees and blew hard enough that I had to pedal back downhill. The
temperature dropped to 43 degrees. After trudging into a bad headwind
both ways, my third fox expedition proved fruitless.

Today, it's about 11 degrees and cloudy with a half-inch of new snow.
No bike ride, but lots of fox tracks along the bluffs. And a fox:

http://i3.tinypic.com/2lt0ahs.jpg

Click on the lower right in Explorer for a larger view. They look a lot
bigger when I surprise them while they're crossing the road down to the
river. They can easily avoid being seen by slow, noisy cars, but not a
bicycle coming around the bend at 35 mph.

CF

synopsis: WARNING: way WAY off-topic: On wild animals, and what they
(and we) do when surprised by each other when we encounter them on our
technically perfect spoke-wheeled bicycles, possible with some fixed
spokes.

Today it was a bald eagle; when they clumsily alight in a medium size
tree it bends halfway to the ground. When in pairs they seem to
know they need a larger tree. They are impressive, and fearless. I'm
almost afraid to stop and intrude, and never have. One was in a ditch
in front of me once, perhaps a little too close for his comfort, so he
took to flight just across the road right in front of me,
causually landed in a small tree at about 6' from the ground, and eyed
me very seriously as I sped past. It didn't occur to me to
interupt my cadence, and I didn't look back, out of respect for his
privacy, much like when you see a celebrity.

Yesterday it was 3 deer comically slipping on a pure ice road in flight
from me on my icebike. They normally stay to the road as long as
possible (those in protected areas that have never learned to fear),
and then casually stroll off it just to the side, but, it being very
icy, I thought it would be fun to accelerate and scare the bejesus out
of them. It was. They had some considerable trouble stabilizing
sufficiently to get off the road into the hard snow on the shoulder.

Recently it was a moose holding his ground, although they
normally flee. He eventually did when I was about 4' from him, but
only reluctantly. Female moose with baby (don't feel like looking up
what they're called) are downright dangerous and very threatening. In a
chance meeting once mom and baby were separated by clumsy me, and baby
fled, mom called, threatened me, and I felt horrible for causing their
distress. Her repeated desperate calling convinced me she thought it
was just the end of her world.

Bighorn Sheep in the off season at Glacier pk will block the (Going to
the Sun) road, and the trails during the tourist season. No recent
photos. Lynx bound across the road at many locales. No confirmed
mountain lions, but have been in the vicinity of sitings. They may be
the most deadly of all and are known for going for the throat of
humans. Elk herds are very well hidden, but often heard in rutting
(sp?) season, and rare, although there was one recently, probably over
100 strong, in a mad dash print on the outskirts of town, through some
ranch land, coming down from altitude at beginning of winter as usual,
and finding a new subdivision, they seemed in a panic, like your
elephants (which I read way back, having a subscription). I
commonly see large herds of deer caught in fenced in areas in the
valley in hunting season in a similar panic. Wolves are very rare, but
present. I saw a lone wolf once and wasn't sure what to do, but have
fled enough dogs in sheer panic, and it was time for an interval
anyway, so I brought the HR up to about 96% for a while, with only a
few quick glances back. He didn't move.

I don't exactly look for
them but the funnest cudliest animals around here are the grizzlies
and black bears (when not in hibranation), and I must have "run into"
at least a dozen bears in the last year, and heard a whole lot more (or
some other large mammal). Often I hear what has just "got to be a bear",
but don't see anything through the brush. There's only a few bear
photos, and they're always way yonder, like your fox.

The transboundary Flathead Valley from NW
Montana up to BC, where I've recently reinvented myself into, known as
Amercica's "wildest valley", and bordering the largest designated
wilderness (Bob Marshall Wilderness Complex) in the 48 states, and
Glacier Pk, with, among other things, the largest griz population in
the Rockies and inland North America. The griz need a LOT of space,
and cannot survive close to man. If you get too close they'll kill you
in a heartbeat, and if they get too close to us we kill them in a
heartbeat. In fact the large majority of grizzly deaths are at the
hands of the government, despite their protected status, which is
itself endangered. There are fewer than 1000 remaining in the 48 states
When they see you they normally just go on merrily digging up the
ground looking for roots/bugs/i don't know what, so long as you
causually slink away.

But surprising black bears is fun sport, especially on a dirt road at
the bottom of a twisty fast descent. You've never seen anything move
so fast (after a discernable expression of sheer terror upon sensing
your presence), and uphill through thick brush at that. I would guess
up to 20 mph up craggy 20% slopes. On the trail the dog knows she
can give full chase, and that 400lb big brown puppy-dog is more
freightened than a,... well just about anything. But telling the
difference is sometimes tricky and I'm just getting the hang of the
subtleties. I'm not so sure about the dog. Late last fall we followed
light snowed 9" tracks about a mile (they like using trails) that were
either a large black or a small grizzly. The end-of-toe to fingernail
distance was significant, indicating a grizzly, which is known for his
very big claws. I'm waiting for the day when dog gives chase to a griz.

In article <[email hidden]>,

Bill Westphal said:

Recently it was a moose holding his ground, although they
normally flee. He eventually did when I was about 4' from him, but
only reluctantly. Female moose with baby (don't feel like looking up
what they're called) are downright dangerous and very threatening. In a
chance meeting once mom and baby were separated by clumsy me, and baby
fled, mom called, threatened me, and I felt horrible for causing their
distress. Her repeated desperate calling convinced me she thought it
was just the end of her world.

Cow and calf.

--
Michael Press