Recycling Bicycle Spokes

If you tension a spoke to its yield stress, imagine what happens to parts of the spoke that have residual tensile stress from cold forming in manufacture and bending into place in a wheel. These locations must have already yielded by then and when relaxed must have the same stress as the remainder of the wire, typically that of the straight sections.

This can be observed in a tensile tester when the spoke is taken to yield stress. Regardless of prior shape, when relaxed the spoke is perfectly straight, its stress memory having been erased because it has plastically deformed (stretched) ever so slightly. I said TO the yield stress, meaning any part that previously had tensile stress exceeded that stress and stretched.

Let's not try to hide behind semantics on this. If you watch spoke wire coming of the spool for manufacturing spokes, it must be stress relieved so that it can be worked. To do that, the wire must be straight and on the reel with its residual stress it coils up when unspooled. To straighten the wire, it is run through the equivalent of degaussing by being run through a series of zigzag rollers with ever decreasing amplitude, both in X and Y. Stretching spoke wire to yield for manufacture would be ungainly while this method of rolling spoke wire as it comes off the reel accomplishes the same thing.

That depends on the material. Spoke wire is about as work hardened as it will get and does not want any heat treatment, especially when this can be done cold. I have observed the method at DT spokes and tensile tested their spokes to assure myself of the value of the process.

I don't know what you mean by "documented process" but there are other ways that do not change material properties and they are as mentioned.

That's why I prefer not to use Carl's pejorative of "squeezing spokes" but rather stretching them to a stress level that will cause yield in the highest stress locations. Squeezing spokes suggests a picture of someone hugging or pinching spokes. That there are high stress locations, ones near or at yield, is certain because spoke elbows take their final form upon tensioning. That forming is plastic and causes yield. Any tensioning thereafter guarantees that the spoke remains at yield at a portion of the bend. Not stress relieving was the main cause of early failures before stress relieving was introduced to wheel building. there were wheel builders who stress relieved without realizing what that part of their process was doing.

Stretching spokes causes highest stress locations to yield and be relieved. However, manually stretching spokes cannot remove all residual stress because stress cannot be manually raised enough.

Major wheel building operations stress relieve by supporting finished wheels laterally on their rims while pushing the hub out of center, first in one direction, then the other. This quick process does not distort the rim because it unloads the near side spokes and does not overload the rim in compression.

Jobst Brandt

[snip]

[snip]

Dear Jobst,

"To stress relieve, grasp the most nearly parallel pairs of spokes at midspan on both sides of the wheel. Your hands should be nearly palm-to-palm. Squeeze the spokes hard."

--"The Bicycle Wheel," 3rd edition, p. 106

"Spoke-squeezing" is a perfectly accurate description in plain English of the process that you recommend in all three editions.

Cheers,

Carl Fogel

Yup. Teaching heat treatment of steel to young'uns. Spokes are quick and easy to harden, and snap like dry spaghetti. When annealed, you can tie knots in them. (Though annealing requires pre-prepared samples. Normalised spokes still snap.) Plus! You can do it all in a regular classroom with just a weeny blowtorch and a tin of water.

Spokes - or hacksaw blades. Spokes are more fun and quicker, but hacksaw blades show differential HT (hard teeth, soft back).

Decisions, decisions. Sometimes I wonder why I don't get an ulcer.

-- Jeff R.

Maybe because you are not infected with Helicobacter pylori?

Makes nice jewelry..If they are DT, I will reuse them if the rim is the same ERD, if I built the wheel orginally.

Quite likely. On of the symptoms of infection is weight loss, and that ain't me, brudder.

(When can one get some of this Helicopter pylon stuff?)

-- Jeff R.

The method of stretching spokes is to grab pairs of spokes and squeeze them together. "Squeezing spokes", taken out of context, distorts the meaning of the operation and leaves the reader with the image of a spoke being pinched or hugged. The operation is to over-stress spokes by stretching them, not by squeezing them.

Of course you know that. Those who read these pages regularly know that you make an effort to distort what people write. You have a way of putting the "em-FASS-is on the wrong "sil-LAB-le" so that selected quotes can be made to sound trivial.

Jobst Brandt

Only if it's the exact same ERD? (not challenging it, just a question.)

Dear Jobst,

The only person distorting things here needs to look in a mirror.

Spoke-squeezing describes Jobst Brandt's recommendation that we squeeze spokes.

Save that quibbling nonsense for your 4th edition, if you ever get around to it.

Cheers,

Carl Fogel

You are busted. Your edition of the method for relieving residual fabrication stress in spokes is misleading, just as Jobst describes. The residual stresses from fabrication are reduced by temporarily elongating the spoke in a tensioned wheel so as to increase the stresses of particular regions of the spoke into plastic deformation.

You are incoherent.

It's Jobst's edition, not mine, and it's Jobst's explicit description of the process:

"To stress relieve, grasp the most nearly parallel pairs of spokes at midspan on both sides of the wheel. Your hands should be nearly palm-to-palm. Squeeze the spokes hard."

--"The Bicycle Wheel," 3rd edition, p. 106

why not indeed - it would be just as effective from a metallurgical viewpoint.

"stress relief" theory as explained in "the book" has no basis in fact. its author doesn't understand the process or the conditions under which it can be achieved - it's merely supposition based on a series of dissimilar and disconnected factoids roughly thrown together without sufficient comprehension. it's only support is the convenient coincidence that the mechanical process itself does actually produce a stable wheel in which spokes remain evenly tensioned and therefor remain much more reliable, but metallurgical "stress relief" as described? pure witchcraft.

That the home shop method for stress relieving spokes is as described does not permit you to substitute `spoke squeezing' for `stress relieving'. Automated machines for building wheels stress relieve the spokes differently. By substituting as you do, you make the process less clear.

Since the question is whether squeezing spokes relieves stress, you're begging the question.

But if you and Jobst insist on making fools of yourselves, I'll start referring to those who believe in the efficacy of spoke squeezing as spoke stretchers.

Meanwhile, go back to squeezing your spokes and writing lengthy explanations of why we shouldn't call it that.

The matter I address is the lengthy explanations you give of `spoke squeezing'. Reassigning to me your indulgences is yet more persiflage.

:-)

I think you catch it from your mother. To be honest, if you don't have it you don't want it.

My thanks for a lively, educational thread.

Doug

threaded end , the nipple is cross threaded or the flats turn into rounds ...... BTW I use old cassette bearing botom brackets that have the strate

15 mm ? shaft , put 6003 bearings on and taper the 6003 outer race and hog out the shell ..... 20 years of "low" friction riding ! The friction is lower than a $200 Campy ! Next i'll do bulk 15mm hard steel tubing and cut an old bike hub and push this tube into it . Next mod the fork to hold the outer race of a 6002 2rs and slip the bearings on the "shaft" , but the quick release is now 2 clamps that bind the 6002's into their beds on the fork .

But rear hub is more exciting . It can be very rigid now ,as the bearings are no where near the hub ! Its one piece ! can be made stronger ...

Shifters must be general purpose spring return levers that return so you can pull again if it did not go far enough . Too much and you must pull the other lever next to it . was it 3 pulls or 4 for 7 th gear ??? No , just pull til noise stops ...

Welded alum frames maybe worse than brazed ... why cant they heat treat the dbl butted alum tube and braze it into alum lugs , worked OK on steel for 100 years ....

snipped-for-privacy@krl.org wrote:

If one combines the writing styles of Peter Chisholm and gene daniels....

-- Tom Sherman - Here, not there. I am supporting cannibalism by eating more nuts.