Spokes breaking at threads?

On 24 Nov, 06:09, Marc wrote:
thirty-six wrote:
On 23 Nov, 21:16, Marc wrote:
thirty-six wrote:
On 23 Nov, 20:24, Marc wrote:
thirty-six wrote:
On 23 Nov, 20:10, Marc wrote:
thirty-six wrote:
On 23 Nov, 18:58, Marc wrote:
thirty-six wrote:
On 23 Nov, 09:11, "Dave Larrington" wrote
about broken spokes:
I had three go at the thread in fairly quick succession on a wheel about
five years old with somewhere over 25,000 km on it. *Replaced 'em and the
wheel behaved itself until such time as it was retired when I got a SON.
That sounds like the spokes were generally suffering bending strains
at the nipple. *If in an unloaded condition the spokes show no hint of
being near a bending condition at the rim, then it can only be due to
a sinking hub when loaded,
Only? There is no other possible reason?
Still no answer?
Unlikely , but possible that the thread has been cut too sharp and
suffered a little corrosion (negated if a cement is used between
nipple and spoke). *Another possibility is that the spoke end have
been misaligned due to faulty installation or later damage caused by
impact
So "then it can only be due to a sinking hub when loaded" *isn't correct?
I would assume that the examination of the wheel was not be made by an
imbecile such as yourself and would have already pointed out such a
problem as simple as a kniked spoke. *As the information as to the
spoke failure was not otherwise forthcoming I find it more than
reasonable to assume that the failure was not obvious and so the
conclusion that it must be failure of the wheel to maintain huh height
is distinctly more than reasonable.
More ********?

No, you really are an imbecile.

Then prove it.

An examination of your postings makes this clear to any reasonable
person. You have already proved you are an imbecile.

On 24 Nov, 09:11, "Dave Larrington" wrote:
,
thirty-six tweaked the Babbage-Engine to tell us:

On 23 Nov, 09:11, "Dave Larrington" wrote
about broken spokes:

I had three go at the thread in fairly quick succession on a wheel
about five years old with somewhere over 25,000 km on it. Replaced
'em and the wheel behaved itself until such time as it was retired
when I got a SON.

That sounds like the spokes were generally suffering bending strains
at the nipple. *If in an unloaded condition the spokes show no hint of
being near a bending condition at the rim, then it can only be due to
a sinking hub when loaded,

This I doubt very much, for two reasons. *Firstly only three spokes broke.
Secondly the hub is unlikely to "sink" on a bike with front suspension.

You haven't supplied much detail as to the wheelbuild, I can only
assume it was a typical bicycle wheel. I was thinking it to be a
tandem wheel (?) which tend to stretch the ability of the rim to
support the nipple at an extreme angle. Even so, unless the spokes
have been damaged by making permanent bends near the threads by
accident or design, they are unlikely to break here unless they are
experiencing active bending with normal wheel loadings. Only by
testing will you know whether a hub will sink wrt the upper part of
the rim.

thirty-six wrote:


Unlikely , but possible that the thread has been cut too sharp

May I interject a bit of pedantry here? Spoke threads are not cut,
they're rolled.

Mine dew, I do have a spoke thread cutter - it will produce a lovely
thread on the end of a spoke, but the spoke is useless as I can't get
nipples for cut threads.

--
Andrew

On 25 Nov, 20:37, Naqerj wrote:
thirty-six wrote:

Unlikely , but possible that the thread has been cut too sharp

May I interject a bit of pedantry here? *Spoke threads are not cut,
they're rolled.

Unless they are cut.

Mine dew, I do have a spoke thread cutter - it will produce a lovely
thread on the end of a spoke, but the spoke is useless as I can't get
nipples for cut threads.

There you go.

Never really taken notice of thread forms. Always got spokes and
nipples together. I believe the spoke threads to be similar to the
electrical BA series. So you may be able to reform a thread, or cut a
14swg in a 15swg nipple, with a BA tap.

thirty-six wrote:
On 25 Nov, 20:37, Naqerj wrote:
thirty-six wrote:

Unlikely , but possible that the thread has been cut too sharp
May I interject a bit of pedantry here? Spoke threads are not cut,
they're rolled.

Unless they are cut.

Which they haven't been for many years.

Mine dew, I do have a spoke thread cutter - it will produce a lovely
thread on the end of a spoke, but the spoke is useless as I can't get
nipples for cut threads.

There you go.

Not really ... it's an ancient bit of machinery.


Never really taken notice of thread forms. Always got spokes and
nipples together. I believe the spoke threads to be similar to the
electrical BA series. So you may be able to reform a thread, or cut a
14swg in a 15swg nipple, with a BA tap.

They're different. 14swg comes about halfway between 8BA and 9BA.
Spokes are an odd thread too. I can't find the numbers at the moment -
I know I've got them somewhere ... but where? - but, for instance, 15,
14 & 13swg all have the same tpi, unlike most normal threads where the
number of tpi increases as the diameter decreases.
--
Andrew

On 26 Nov, 21:31, Naqerj wrote:

Not really ... it's an ancient bit of machinery.

Never really taken notice of thread forms. *Always got spokes and
nipples together. *I believe the spoke threads to be similar to the
electrical BA series. *So you may be able to reform a thread, or cut a
14swg in a 15swg nipple, with a BA tap.

They're different. *14swg comes about halfway between 8BA and 9BA.
Spokes are an odd thread too. *I can't find the numbers at the moment -
I know I've got them somewhere ... but where? - but, for instance, 15,
14 & 13swg all have the same tpi, unlike most normal threads where the
number of tpi increases as the diameter decreases.

I think that thread form has changed to that thirty years ago in
common usage. Even the English cheap spokes I got ten years ago seem
to be the same thread as a DT. There seemed to be a difference
between English and continental spokes thirty years ago. Same pitch,
slightly different diameter meant you could force a tight nipple onto
a spoke, dont know which way it was, but sure hurt my fingers with a
cyclo mini spoke key.

If the thread pitch was coarser for the thicker spokes then it would
be difficult to set the spoke length accurately and a strong hand
would be needed using a regular tool. It would also make it more
difficult for the buider to go between spoke gauges because of the
difference in feel at the nipple key. I think the pitch is based on
the 15swg in the BA series and maintained for 14 and (you say) 13.
12 is likely to be different for it is a motorcycle gauge and they use
a nipple key more like a typical crescent wrench.