stress relieve methods
Matt Frankland
The crankarm method seems to be favored in this newsgroup, although all
the wheelbuilders i'm apprenticed to have never used it or heard of it.
They use either the 'grab 4 and squeeze really hard' method or put it on
the floor and stand on it in sections. Or they won't tell me what they
really do, I'm not always sure.
I just finished my rolf cert. build using their wine press method. (For
those not familiar, its a table with a round hole just smaller than the
rim diameter supporting the laced wheel, and the hub is pressed
laterally to the rim, with a torque wrench. Flip the wheel and do the
other side, etc.)
The 'overpriced wisconsin wheels' method was interesting,
...does anyone use this method for traditional 3x and higher spoke count
wheels? I have it around anyway, and it was pretty expensive for the
shop so I might as well use it.
...is it as effective or superior to other favorite methods from someone
using both methods on comparative wheels? It seems to be a more uniform
way to stress all the spokes evenly, if uniform stressing matters
...if you are, what tensions are you using for conventional wheels? Rolf
being 85 ft/lbs. I'm not looking for an exact number, just a range or
recommended starting point.
Thanks,
Matt
David Green
news:3A270C17...@mindspring.com...
> The crankarm method seems to be favored in this newsgroup, although all
> the wheelbuilders i'm apprenticed to have never used it or heard of it.
I can't remember this method being mentioned much, let-alone favoured, much
in this newsgroup. Certainly, Sheldon Brown's wheelbuilding page is
mentioned regularly (which describes this method), but then so is Jobst
Brandt's book which doesn't.
> They use either the 'grab 4 and squeeze really hard' method or put it on
> the floor and stand on it in sections.
Maybe, as you are making wheels for a living, you ought to get a copy of
'the Bicycle Wheel' for Christmas? Then, you'd be able to explain to these
guys why the 'put it on the floor and stand on it in sections' method is no
good.
> The 'overpriced wisconsin wheels' method was interesting,
Never heard of this. Care to explain?
David Green.
Matt Frankland
David Green wrote:
> > They use either the 'grab 4 and squeeze really hard' method or put it on
> > the floor and stand on it in sections.
> Then, you'd be able to explain to these
> guys why the 'put it on the floor and stand on it in sections' method is no
> good.
Sadly then, Trek/Fisher/Klein/Lemond just released their mechanic
certification study guide 2 weeks ago mentioning this method only under
wheel truing. Email me if interested in seeing.
> > The 'overpriced wisconsin wheels' method was interesting,
>
> Never heard of this. Care to explain?
I'm just poking fun at the Rolf wheels here, since they are made by
Trek. I'm just referring to the wine press again. I didn't coin the
phrase, but liked it when I first heard it. Rolf wheels have fairly
heavy rims to support the paired spoking and the stress cycles it is
subjected to to build it in the press (about five times). Opinions of
some is that they are neat looking but actually not that light for
$6-700 a set, hence the phrase.
Matt
Alex Rodriguez
>> > The 'overpriced wisconsin wheels' method was interesting,
>>
>> Never heard of this. Care to explain?
>
>I'm just poking fun at the Rolf wheels here, since they are made by
>Trek. I'm just referring to the wine press again. I didn't coin the
>phrase, but liked it when I first heard it. Rolf wheels have fairly
>heavy rims to support the paired spoking and the stress cycles it is
>subjected to to build it in the press (about five times). Opinions of
>some is that they are neat looking but actually not that light for
>$6-700 a set, hence the phrase.
Colorado Cyclist also uses a similar device. I recall seeing a picture
of their device that uses a hydraulic press in one of their catalogs.
--
-----------------
Alex __O
_-\<,_
(_)/ (_)
Tom Biery
Bang your head against the wall!
Jobst Brandt
> The crankarm method seems to be favored in this newsgroup, although
> all the wheelbuilders I'm apprenticed to have never used it or heard
> of it. They use either the 'grab 4 and squeeze really hard' method
> or put it on the floor and stand on it in sections. Or they won't
> tell me what they really do, I'm not always sure.
Grabbing 4 and squeezing hard is the only way one can do this manually.
The other methods do little or nothing for the spokes. Pressing down
on the rim with the axle as opposing force, whether by standing on it
or pushing with the hands only serves to slacken the under side
spokes. It does not appreciably increaser tension on the upper side.
> I just finished my Rolf cert. build using their wine press method.
> (For those not familiar, its a table with a round hole just smaller
> than the rim diameter supporting the laced wheel, and the hub is
> pressed laterally to the rim, with a torque wrench. Flip the wheel
> and do the other side, etc.)
This does not adequately stress relieve the spokes. The box is useful
for tightening spokes because it unloads the under side spokes, but it
does not do a good job at stress relief. It helps for tightening flat
spokes that require such unloading while tensioning as do spokes in
wheels with so few spokes, because they must be more than twice as
tight as wheels with a full complement of 36. At such high tension,
spokes easily twist off from thread ramp and friction torque.
> The 'overpriced Wisconsin wheels' method was interesting,
I'm not familiar with that method.
> ...does anyone use this method for traditional 3x and higher spoke
> count wheels? I have it around anyway, and it was pretty expensive
> for the shop so I might as well use it.
> ...is it as effective or superior to other favorite methods from
> someone using both methods on comparative wheels? It seems to be a
> more uniform way to stress all the spokes evenly, if uniform
> stressing matters ...if you are, what tensions are you using for
> conventional wheels? Rolf being 85 ft/lbs. I'm not looking for an
> exact number, just a range or recommended starting point.
I take it the Wisconsin method to which you refer is the Rolfing box.
This does not do a good job. Besides, you can collapse a rim with it
if the wheel has more than 20 spokes because the increase in tension
is greater than the loss to the under side spokes. On the other hand
it is an alternate method and one that does some good. However, with
paired spokes, it seems that a special tool to squeeze these pairs
would be far more useful, simpler and less cumbersome.
Jobst Brandt <jbr...@hpl.hp.com>
kam
is manually, by squeezing the spokes in sections?
I don't understand why the Rolf "wine press" does not adequately stress
the spokes--b/c the wheels go through about 5 of these stress cycles in
the building period, and after each one, it is necessary to go back and
bring the spoke tensions back up at least for the first 3 stress
cycles. I haven't been rolf certified to build/fix these wheels, so all
my questions here are from watching the whole process (while someone
else in the shop i work at was completing their certification).
Could the Rolf wheel stressor/press be used on a regular wheel, like a
32 3-cross wheel, or would it totally just bust the entire wheel apart?
Is the Rolf press actually "stretching" the spokes when tension is put
on by the press? 85 ft lbs is alot to put laterally on the hub. The
manual that comes with the press/video says nothing about exactly *how*
the press works on the spokes.
TIA for any answers to my many questions...:)
mtbgrrl
Matt Frankland
> I take it the Wisconsin method to which you refer is the Rolfing box.
> This does not do a good job. Besides, you can collapse a rim with it
> if the wheel has more than 20 spokes because the increase in tension
> is greater than the loss to the under side spokes. On the other hand
> it is an alternate method and one that does some good. However, with
> paired spokes, it seems that a special tool to squeeze these pairs
> would be far more useful, simpler and less cumbersome.
Which way would I expect the rim to collapse when using more than 20
spokes? Would it potatoe or the spoke bed folding/cracking around the
rim? I don't see how it can potatoe while I press it, since its the top
side that is de-tensioned, the bottom spokes are stretched as the hub is
pushed down and the table of the box supports the rim. When I back the
press off the hub, the rim could potatoe then?
One downside to the box is that one entire side is stressed before the
other. It can be quite out of dish halfway through a cycle, Is this
another time to expect the rim to misshapen?
Matt Frankland
> The wheel would taco although it might only be visible when backing
> off the load on the wine press. The reason is that to stress relieve,
> the spoke must be largely over tensioned and at that tension for many
> spoke, the compressive load of the rim would be exceeded. On the
> other hand, I don't know that people are making their Rolfs adequately
> tight. How do you find how tight to make them? I assume they give a
> tension specification that they determined somehow.
The exact readings from their tensionometet is given.
A very robotic process, each Rolf wheel type has 5 tension ranges given,
as the wheel is pressed 4 times, each time the tension is increased
about 10 lbs, then pressed again. The tensionometer is used more often
than the spoke wrench. Its a very robotic process. The only challenge
was the parts supplied are seconds, giving some interesting rim welds to
compensate for. The hubs were seconds as well.
Matt Frankland
press is unwinding the spokes since they are held fairly flat when
tensioned anyway.
Tim McNamara wrote:
>
> Stress relieving requires that the spoke tension be increased
> significantly, above their (if I have the term and concept right) plastic
> deformation threshhold. This relieves internal stresses within the metal
> of the spoke left over from manufacturing (drawing the spoke through wire
> dies and bending the elbow), which in turn increases the service life of
> the spoke.
>
> Pushing the rim to one side, walking on the spokes, etc. does not
> increase spoke tension significantly. It does reduce the tension on some
> spokes which allows them to release their wind-up (twist) that occurred
> while tightening them. Some satisfying pings are often heard when the
> spoke is unloaded. But that's not stress relieving.
Jobst Brandt
>> I take it the Wisconsin method to which you refer is the Rolfing
>> box. This does not do a good job. Besides, you can collapse a rim
>> with it if the wheel has more than 20 spokes because the increase
>> in tension is greater than the loss to the under side spokes. On
>> the other hand it is an alternate method and one that does some
>> good. However, with paired spokes, it seems that a special tool to
>> squeeze these pairs would be far more useful, simpler and less
>> cumbersome.
> Which way would I expect the rim to collapse when using more than 20
> spokes? Would it potato(e) or the spoke bed folding/cracking around
> the rim? I don't see how it can potato(e) while I press it, since
> its the top side that is de-tensioned, the bottom spokes are
> stretched as the hub is pushed down and the table of the box
> supports the rim. When I back the press off the hub, the rim could
> potato(e) then?
The wheel would taco although it might only be visible when backing
off the load on the wine press. The reason is that to stress relieve,
the spoke must be largely over tensioned and at that tension for many
spoke, the compressive load of the rim would be exceeded. On the
other hand, I don't know that people are making their Rolfs adequately
tight. How do you find how tight to make them? I assume they give a
tension specification that they determined somehow.
> One downside to the box is that one entire side is stressed before
> the other. It can be quite out of dish halfway through a cycle, Is
> this another time to expect the rim to misshapen?
Rear wheels won't get their due on the right side at all. Check the
diagram for rear wheels in "the Bicycle Wheel" and that becomes
obvious. Spoke tension does not increase much no matter how hard you
press. It's a matter of cosine error of a too small angle... no
length change to speak of.
Jobst Brandt <jbr...@hpl.hp.com>
Tim McNamara
Qui si parla Campagnolo
is manually, by squeezing the spokes in sections? >>
Yes, put on some gloves and give the wheel a workout-
<< I don't understand why the Rolf "wine press" does not adequately stress
the spokes >>
Because pushing on the rim doesn't really stress relieve the spokes facing
upward.
<< I haven't been rolf certified to build/fix these wheels, >>
Can ya build a wheel?True/tension/round/dish a wheel well?
Then you are 'Rolf certified'-
<< The
manual that comes with the press/video says nothing about exactly *how*
the press works on the spokes >>
Peter Chisholm
"Vecchio's" Bicicletteria
1833 Pearl ST.
Boulder, CO
(303)440-3535
http://www.vecchios.com
dvt
> The crankarm method seems to be favored in this newsgroup, although
all
it.
> They use either the 'grab 4 and squeeze really hard' method or put it
on
> the floor and stand on it in sections.
You'll hear plenty of people say that the crankarm (or other lever)
method does not work. You need to 'grab 4 and squeeze.' I disagree.
Here's how to make the lever method work: Do it on *both* sides of the
wheel at the same time. If you do it on one side, you won't get enough
stress on the spokes. I think many people use the lever one side at a
time, and I agree that this is insufficient. Two levers, one on each
side, applied to opposing spokes, is much easier on the hands than the
grab and squeeze method.
Dave
dvt at psu dot edu
Jobst Brandt
>> The wheel would taco although it might only be visible when backing
>> off the load on the wine press. The reason is that to stress
>> relieve, the spoke must be largely over tensioned and at that
>> tension for many spoke, the compressive load of the rim would be
>> exceeded. On the other hand, I don't know that people are making
>> their Rolfs adequately tight. How do you find how tight to make
>> them? I assume they give a tension specification that they
>> determined somehow.
> The exact readings from their tensionometet is given. A very
> robotic process, each Rolf wheel type has 5 tension ranges given, as
> the wheel is pressed 4 times, each time the tension is increased
> about 10 lbs, then pressed again. The tensionometer is used more
> often than the spoke wrench. Its a very robotic process. The only
> challenge was the parts supplied are seconds, giving some
> interesting rim welds to compensate for. The hubs were seconds as
> well.
Just for the record, the instrument is a tensiometer. I know that W
invents scrabble words but this does not make them correct.
The repeated stress relieving is a misunderstanding of the effect.
Either the stress is high enough to relieve residual manufacturing and
installation stresses or it is not. If it is, then it need be applied
only once. The repeated loading in the 'wine press' is hocus-pocus.
I can't imagine what the inventor of this process thinks is occurring,
but it does not improve spoke durability. Once, and at the highest
tension, is adequate. The others before that are wasted effort and
accomplish nothing.
Jobst Brandt <jbr...@hpl.hp.com>
Jobst Brandt
>> The crankarm method seems to be favored in this newsgroup, although
>> all the wheelbuilders I'm apprenticed to have never used it or
>> heard of it. They use either the 'grab 4 and squeeze really hard'
>> method or put it on the floor and stand on it in sections.
> You'll hear plenty of people say that the crankarm (or other lever)
> method does not work. You need to 'grab 4 and squeeze.' I disagree.
Maybe you could expand on your disagreement and whether it does not
produce the desired result or whether it doesn't agree with your
hands. The need for this process was developed in conjunction with
writing "the Bicycle Wheel" before which it was unknown and its
absence was the cause of most spoke failures. I have always done it
with good success with bare hands, although I would wear gloves if I
built many wheels.
> Here's how to make the lever method work: Do it on *both* sides of
> the wheel at the same time. If you do it on one side, you won't get
> enough stress on the spokes. I think many people use the lever one
> side at a time, and I agree that this is insufficient. Two levers,
> one on each side, applied to opposing spokes, is much easier on the
> hands than the grab and squeeze method.
I don't know how you propose bending spokes with a lever, but the
method shown on Sheldon Brown's web page introduces residual stress at
spoke crossings that are strongly bent by the method shown. If spoke
crossings are driven apart by the method, tension is not raised enough
to do any good. The best way is in a truing machine with a pneumatic
piston pressing against the midspan of a single opposing spoke pair
toward the central plane. This method is not practical for the manual
builder.
I see all these arguments to be driven by soft skin or weak hand grip.
That is unfortunate because it takes a strong grip to do any good in
the absence of a truing machine by BMD or Holland Mechanics.
Jobst Brandt <jbr...@hpl.hp.com>
Sheldon Brown
> I don't know how you propose bending spokes with a lever, but the
> method shown on Sheldon Brown's web page introduces residual stress at
> spoke crossings that are strongly bent by the method shown.
I've never had a spoke fail at this location.
Even on a theoretical level, I don't believe this assertion is correct.
In the absense of this technique, the spokes will be curving around one
another at the laced crossing, which would, theoretically introduce
residual stresses.
With my system using an old crank, the spokes actually run straighter on
their unsupported length, with a comparatively sharp bend at the laced
cross. I don't believe there are any important residual stresses at
this bend. The action of the lever (crank) bends them farther, then
they relax back to the new rest position. Thus, I believe that any
theoretical residual stresses at the laced crossing are relieved by the
same operation that stress relieves the spoke elbow.
> I see all these arguments to be driven by soft skin or weak hand grip.
> That is unfortunate because it takes a strong grip to do any good in
> the absence of a truing machine by BMD or Holland Mechanics.
So, should my delicate, sensitive hands disqualify me as a wheelbuilder?
Many tasks that used to be done by brute strength are accomplished
equally well or better by the use of leverage.
Sheldon "Mechanical Advantage" Brown
+------------------------------------------------------+
| One of my very favorite singer/songwriters is the |
| French folkie Gabriel Yacoub |
| His discs are hard to find, but worth looking for, |
| both his solo work and his earlier recordings with |
| the Breton group Malicorne. |
| http://sheldonbrown.com/music.html |
+------------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772, 617-244-1040 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com
Qui si parla Campagnolo
I can't imagine what the inventor of this process thinks is occurring,
but it does not improve spoke durability. >>
Of course but how else can Mr Rolf come up with an idea of how to 'stress
relieve' paired spokes?
Maybe he's using the 'wine press' to press grapes and then drinkin' it-
CV2572
writes:
>Bang your head against the wall!
You talking about all the political "discussion" on this newsgroup?
Robin Hubert
dvt
news:90bu3j$cs3$5...@hplms2.hpl.hp.com...
> Dave vt? writes:
> > You'll hear plenty of people say that the crankarm (or other lever)
> > method does not work. You need to 'grab 4 and squeeze.' I disagree.
>
> Maybe you could expand on your disagreement and whether it does not
> produce the desired result or whether it doesn't agree with your
> hands.
Choice B. It doesn't agree with my hands. I've tried the squeeze method,
it seems to work, but I would rather use a lever.
> I don't know how you propose bending spokes with a lever, but the
> method shown on Sheldon Brown's web page introduces residual stress at
> spoke crossings that are strongly bent by the method shown.
As Sheldon already pointed out, the residual stress at spoke crossings is a
non-issue. Perhaps you have seen spokes break in the middle, but I haven't.
> If spoke
> crossings are driven apart by the method, tension is not raised enough
> to do any good.
Hmmm. I don't understand this. The temporary over-stress can be estimated
if you know the displacement of the spoke from its rest position. If you
displace the spoke equally with either method, the tension should be raised
the same independent of the method used. Why then would the is the tension
"not raised enough to do any good?"
> I see all these arguments to be driven by soft skin or weak hand grip.
I agree.
> That is unfortunate because it takes a strong grip to do any good in
> the absence of a truing machine by BMD or Holland Mechanics.
I disagree.
Jobst Brandt
>> I don't know how you propose bending spokes with a lever, but the
>> method shown on Sheldon Brown's web page introduces residual stress
>> at spoke crossings that are strongly bent by the method shown.
> I've never had a spoke fail at this location.
> Even on a theoretical level, I don't believe this assertion is
> correct. In the absence of this technique, the spokes will be
> curving around one another at the laced crossing, which would,
> theoretically introduce residual stresses.
Spokes not subjected to this method may curve around one another but
that angle is small and fairly constant. In contrast, if it is
accentuated as the lever method does, the bend is sharper (and more
local), having some spring-back and therefore, locked in stress. The
reason I mention this is not because I have seen such a wheel fail but
because I have had mid-spoke failures from such bends caused by a
foreign object in the wheel on trails. The difference may be that
this is a supported kink, while mine was not. In any case it
introduces residual stress, something that can be assessed by removing
the spoke from the wheel to see if it is straight or retains a kink.
> With my system using an old crank, the spokes actually run
> straighter on their unsupported length, with a comparatively sharp
> bend at the laced cross. I don't believe there are any important
> residual stresses at this bend. The action of the lever (crank)
> bends them farther, then they relax back to the new rest position.
> Thus, I believe that any theoretical residual stresses at the laced
> crossing are relieved by the same operation that stress relieves the
> spoke elbow.
I think "relax top a new rest position" is incorrect. I think you'll
find that taking one of these spokes out of the wheel will reveal that
it retains a greater angle than it has in the wheel. This can be
assessed by holding the loose spoke, taken from the wheel, next to one
under tension in the wheel.
>> I see all these arguments to be driven by soft skin or weak hand
>> grip. That is unfortunate because it takes a strong grip to do any
>> good in the absence of a truing machine by BMD or Holland Mechanics.
> So, should my delicate, sensitive hands disqualify me as a
> wheelbuilder? Many tasks that used to be done by brute strength are
> accomplished equally well or better by the use of leverage.
I agree, although a better method could be found, if need be. The
existence of residual stress in this case may be academic. I have no
experience with it and will probably not have opportunity to asses it
myself. I'll take your word for it. On the other hand, I don't know
how much over-tension the method achieves. The geometry obscures what
spoke tension increase the lever force causes.
Jobst Brandt <jbr...@hpl.hp.com>