Andrew Lee' whatsupandrewathotmaildotcom said:
"jim beam" <[email hidden]> wrote in message news:TlcWa.2571
Quoted message said:what i like most - and i'm talking from a materials viewpoint here - is that they're drawn not
hammered [d.t.] or ground [wheelsmith?] into their butted profiles. also, the spoke elbows are
not scarred in their bending process like other manufacturers. it may not seem like a big deal,
but being as most spokes break from fatigue, and this usually initiates at surface defects at the
spoke elbow, it can have a big influence on the life of the spoke. you can see this for yourself
with a magnifying glass.
What? Hammered? Ground??!! All quality spokes are drawn. I guess the spoke head could be said to be
"hammered"... it's cold formed. Stress relieving the wheel removes residual manufacturing stress in
the elbow. I don't know if Sapim fewer surface defects than DT or Wheelsmith, but I wasn't aware
that it was a major problem in the first place. Here's what Jobst says about spoke forming:
Quoted message said:Where do you folks get all this stuff. Spoke wire is drawn to its diameter in a swaging process.
"Butted" spokes are selectively swaged in their midspans, DT having what they call a patented
process that causes such a smooth transition that it is difficult to see. Others use more abrupt
methods, leaving discontinuities that are easily seen. They are all swaged, that is the diameter
is reduced by working, not material removal.
All due respect to both you and Jobst but swaging and drawing are different process, it is not
unreasonable to describe swaging as hammering...
efunda.comswaging.cfmOpen ↗
in order to vary a diameter in the draw process the speed that the wire is drawn through the draw
die must be varied (unless using a split die which would be inappropriate if not impossible), a
faster speed will result in a narrower diameter ... this process would also make the heading
operation more difficult..
There is another spoke maker (I can't remember which) that really does appear grind the butted
sections, there is a sharp discontinuity between the different diameters, however the cost of
grinding would be very high and I suspect they are simply flat rolled.
Actually I suspect that all spokes are flat rolled (cold rolled), it is a far less expensive process
than either grinding or swaging (if you really stretch a point you might even call it
swaging...hmmmm). it is more controllable and far more flexible, and in almost every way would
provide the same benefits as "swaging"
efunda.comcold rolling.cfmOpen ↗
FWIW drawing and swaging both have their benefits and drawbacks. From the stand point of a spoke I
think I would prefer a swaged spoke (cold rolled)... the metals crystal structure would be finer and
more uniform.
In any event there is so much "market speak" surrounding what is really a simple process it is
difficult to believe anything these manufacturers claim.