1892 Spoke Failures

[The spokes breaking below in 1892 were direct, meaning that they were
straight and screwed into the hub instead of using an elbow and a
flared end.]

THE TRUE CAUSE of the breaking of spokes is such an important and
little understood matter that the following article from the "Irish
Cyclist" is of value to manufacturer, repairer and dealer alike:

Thanks to the thoughtful attention bestowed upon his customers by Mr.
J.W. Hayes. the intelligent and go-ahead cycle agent of Enniscorthy,
we are able to present for the consideration of the trade, and those
versed in the science of metallurgy, a new aspect of the problem of
why some kinds of spokes seem to break chronically and incurably.

Mr. Hayes has discovered a peculiar liability of spoke-wire to snap
under certain conditions, but to unaccountably cast off their
brittleness and become tough and strong, merely by the alteration of
the shape of the threads cut upon them.

Although this peculiarity may, perhaps, have been known to others, we
have never seen it published, nor has any scientific explanation been
forthcoming; and the point is one of such extreme importance to the
cycle trade and riders that we reproduce Mr. Hayes' letter to us
almost in its entirety, including some valuable hints on
spoke-breaking, and commend it to the caruful consideration of our
readers in the trade.

After prefacing his remarks with the explanation that he is anxious to
build wheels suited to riders of different weights, Mr. Hayes says:

"The only question I have now undecided is the amount of butting I am
to allow to project over the hub-flange to obtain the best results,
i.e., ought I have them short butts or long butts? From a close study
of the matter I lean to the long butts, but I tried many different
ways of curing defective machines the last few years, viz.:

(1) I put plain spokes in the front wheels, and butted ones behind.

(2) I put heavy butted spokes on the chain wheel side of a rear wheel,
and light butted on the other side.

(3) I increased the number of spokes in the hind wheel;

and

(4) diminished the size of rear wheels, and so on;

but last week I met a wheel which puzzled me considerably, so I
experimented upon it, and give you the result, and want you to explain
to me the scientific reason for a certain fact.

History of a Wheel: I purchased a wheel some time ago from a London
firm; it had Bown's hubs (best quality) and thirty-six plain, strong
spokes (a driving wheel it was); but Bown did not put the spokes in.

The spokes were 10-gauge wire, and came built in, and all ready for
the tyre and enamel [spokes were often enameled as an alternative to
nickel-plating in the pre-stainless era]. Well, I put the wheel in a
machine and hired it out. On the flrst ride eight spokes snapped off
in the hub. I got new ones in, sent it out again and six more snapped;
I got these in and lent it to a young fellow, nine stone weight, to
ride to Kilkenny; when he got there he found he had snapped twelve
spokes; he had new ones put in there, and rode home, snapping five on
the home journey.

When he told me the tale I was so disgusted that I wired to Bown for a
new hub, thinking all the time that it was the fault of the hub, as
had never seen anything so bad before.

The matter was quite a puzzle to me. My man took all the spokes out,
intending to throw awav the hub; but, on examination, he found the hub
perfectly sound. The two of us then examined the whole of the spokes,
and we discovered that none of the spokes we had put in ourselves had
snapped, nor had any of the twelve the Kilkenny man had put in
snapped, but only the original spokes, of which there now remained but
five. We looked sharply at these five, but could detect nothing
unusual about them. The thread was close, beautifully finished, but
deep, and the edges of the thread very sharp. We were at a loss how to
account for the snapping, so I said, 'Let us put the spoke in the vise
and see how much it would bend without snappimg; so we put the thread
in the vise just as if it had been in the hub and bent the spoke
(sprung it sideways, as it would be sprung in case of a heavy pull on
the chain).

Well, I had not sprung it to an angle of forty-five, when it snapped
off. I then tried one of our own threaded spokes of same diameter, and
was able to bend it down to nearly eighty degrees before it snapped.
Whereupon, I immediately jumped to the conclusion that the original
spokes must have been too brittle, and would have remained under this
impression if I had not experimented further; but I was not satisfied.

I said to my man, 'Put a thread with our own tap on one or these
original spokes, and see will it snap the same way.'

He did so, and judge of my astonishment when I found that the same
spoke, which, when threaded with the original thread, had snapped
before it was sprung to an angle of forty-five, now (when my own
thread was on it) could be bent nearly to eighty without snapping; so
you see the whole trouble was in cutting the thread. By whatever
system of machinery the original spokes were threaded the cohesive
force was weakened much on the same plan, and for the same reason,
that a scratch with a diamond on the surface of a pane of glass causes
the glass to snap off readily along the line of the scratch, no matter
how thick the glass is. For the very same reason a sharp cut or a file
mark with a sharp edge on a piece of wire or iron bar will cause it,
when bent, to 'give' at that point; no doubt, to this cause is to be
attributed the snapping of spokes now and then in the hubs of even the
best machines, the thread being too deep or too sharp.

"Now, can you tell me the reason why such a thing occurs? How is
molecular structure of a substance affected by a sharp cut on the
surface? Next, how is it to be best avoided or counteracted? I want
you to look into the matter, as it is of considerable importance in
the building of a wheel. If all spokes are more liable to snap at the
sharp angle of the upper thread than anywhere else, then the further a
spoke is screwed home i. e., the more the last thread disappears into
the hub the better for if two or three threads project above the hub
not alone does the rain settle in the thread and rust it, but the
tendency to snap is greater than when the upper thread has the edge of
the hub to lean against, as it were. Again, if the butts are long and
project half an inch above the hub, I imagine the strain or twist is
removed further up the spoke, where it can afford to bend without
snapping and can easily spring back again.

I think, also, that the less shoulder a butt has the better; i.e., it
is better for the butt to taper off until it is thinned down to the
diameter of the body of the spoke, as there will then be no angles to
snap at.

Another thing, a wide and deep flange saves the spokes, for obvious
reasons, but there must be a limit to the depth of the flange, because
if made too deep it would be too heavy--of course you could gO on
deepening it until it became a mere dish. Now, it strikes me that
where you allow the solid unthreaded butts to project half an inch
from the hub you have all the advantages of a wider flange without the
weight of a solid flange, because the projecting butts give a rigidity
to the wheel which it would not otherwise have, and you can have the
remainder of the spokes very much lighter.

Thus the old (1) Singer challenge butted and tapered spoke appears to
me to be the best, and next come (2) Hillman and Herbert's long butted
spoke; (3) the Coventry Machinists' Co.'s spokes come next, but they
have the shoulder too sharp, and (4) next come Humber and J. K.
Starley's, and (5) Bayliss and Thomas. The rest don't count, as very
few of them are fit to built a wheel for Irish road at all. They make
fair enough path [race-track] machines and wheels for pneumatics [as
opposed to the solid and hollow-cushion tires still in use].

From a consideration of these makes and from the nature of the repairs
we have to make on them, I derive the foregoing conclusions.

--Sporting Life, June 25th, 1892

http://la84foundation.org/SportsLibr.../SL1913006.pdf

Cheers,

Carl Fogel

wrote:

(3) I increased the number of spokes in the hind wheel;

I am so going to start calling the rear wheel the "hind" wheel.

--
Mike "Rocket J Squirrel"
Bend, Oregon

Mike Elliott wrote:
wrote:

: (3) I increased the number of spokes in the hind wheel;

:I am so going to start calling the rear wheel the "hind" wheel.

You'll have to call the one in front the "fore" wheel, too.

--
sig 4

On 27 Apr, 06:56, wrote:
[The spokes breaking below in 1892 were direct, meaning that they were
straight and screwed into the hub instead of using an elbow and a
flared end.]

THE TRUE CAUSE of the breaking of spokes is such an important and
little understood matter that the following article from the "Irish
Cyclist" is of value to manufacturer, repairer and dealer alike:

Thanks to the thoughtful attention bestowed upon his customers by Mr.
J.W. Hayes. the intelligent and go-ahead cycle agent of Enniscorthy,
we are able to present for the consideration of the trade, and those
versed in the science of metallurgy, a new aspect of the problem of
why some kinds of spokes seem to break chronically and incurably.

Mr. Hayes has discovered a peculiar liability of spoke-wire to snap
under certain conditions, but to unaccountably cast off their
brittleness and become tough and strong, merely by the alteration of
the shape of the threads cut upon them.

etc.

Stress concentration at the thread root is minimised with a Whitworth
or BA type thread which has been adopted for bicycle spokes. Having
the spoke length adjustment by a nipple which is able to articulate
slightly in its mounting also helps.

On Apr 26, 10:56*pm, wrote:
so I said, 'Let us put the spoke in the vise
and see how much it would bend without snappimg; so we put the thread
in the vise just as if it had been in the hub and bent the spoke
(sprung it sideways, as it would be sprung in case of a heavy pull on
the chain).

Radial laced as well as having spoke nipples at the hub?

-pm

On 27 Apr, 19:38, pm wrote:
On Apr 26, 10:56*pm, wrote:

so I said, 'Let us put the spoke in the vise
and see how much it would bend without snappimg; so we put the thread
in the vise just as if it had been in the hub and bent the spoke
(sprung it sideways, as it would be sprung in case of a heavy pull on
the chain).

Radial laced as well as having spoke nipples at the hub?

-pm

The hub was drilled and threaded, usually gun brass, the wire spokes
screwed direcly into them. Spoke length was adjusted by gripping the
spoke directly and turning. I know that some manufacturers used
regular type pliers, but cant help thinking that there was a cam
operated tool in use at the time specifically designed for this.

On Tue, 27 Apr 2010 11:38:59 -0700 (PDT), pm
wrote:

On Apr 26, 10:56*pm, wrote:
so I said, 'Let us put the spoke in the vise
and see how much it would bend without snappimg; so we put the thread
in the vise just as if it had been in the hub and bent the spoke
(sprung it sideways, as it would be sprung in case of a heavy pull on
the chain).

Radial laced as well as having spoke nipples at the hub?

-pm

Dear pm,

Early spoke designs and terminology are a nightmare.

Yes, early safety-bike direct-spoke hubs were laced radially, just
like highwheelers:
http://www.hochrad.info/hochradbilde...chen200gif.gif

A direct-spoke just threads directly into the hub and is laced
radially.

But there's no threaded nipple at the hub, just a hole tapped into the
hub.

If there's a nipple at the hub, you've got a lock-nutted spoke, a more
complicated design that used an unthreaded spoke with a flared end,
also laced radially:
http://www.hochrad.info/hochradbilde...-mutterauf.jpg

In contrast, there were straight-pull spokes, which were just straight
spokes (no elbow) whose flared ends pulled through an unthreaded
hub-hole and were laced at a tangent--modern hubs are using this
design again.

The terms and designs are easily confused, and nothing stopped oddball
manufacturers from making unthreaded "direct-pull" radial hubs or
threaded "straight-pull" tangent hubs.

A later tangent-laced straight-pull hubs with unthreaded spoke heads:

http://www.nostalgic.net/index.asp?S...ull+hubs+1.jpg

http://www.nostalgic.net/index.asp?S...ull+hubs+2.jpg

http://www.nostalgic.net/index.asp?S...ull+hubs+3.jpg

http://www.nostalgic.net/index.asp?S...ull+hubs+4.jpg

An even later unthreaded straight-pull spoke hub with its spokes in
place:

http://www.nostalgic.net/index.asp?S...ll+rear+hu.jpg

***

By 1900, most hubs used modern elbow spokes.

Some used tricks like this to make repair easier:
http://www.nostalgic.net/index.asp?S...adie+hub+1.jpg
http://www.nostalgic.net/index.asp?S...adie+hub+2.jpg

Others were fussy about which way the spoke was inserted:
http://www.nostalgic.net/index.asp?S...1+EZ+hub+1.jpg
http://www.nostalgic.net/index.asp?S..._Atherton1.jpg

http://www.nostalgic.net/index.asp?S...rkop+hub+3.jpg

Cheers,

Carl Fogel

On Apr 27, 10:44*am, David Scheidt wrote:
Mike Elliott wrote:
wrote:

: (3) I increased the number of spokes in the hind wheel;

:I am so going to start calling the rear wheel the "hind" wheel.

You'll have to call the one in front the "fore" wheel, too. *


"Fore wheels bad, two..." oh, I'm sorry. Wrong homonym.

On 27 Apr, 21:22, Jobst Brandt wrote:
I find important to not ovelook that fatigue failures are better
understood today than in the days of that publication, and that spokes
are cold formed, using rolled threads in which the root of the thread
is under compression when formed.

Jobst Brandt

woof

Mike Elliott wrote, On 4/27/2010 10:28 AM:
wrote:

(3) I increased the number of spokes in the hind wheel;

I am so going to start calling the rear wheel the "hind" wheel.

No no no! Its the aft wheel.

Also, the drive chain goes on the starboard side



--

Paul D Oosterhout
I work for SAIC (but I don't speak for SAIC)