Torpedo 5-speed pulley photo

Emanuel Berg

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Jul 10, 2016, 2:51:59 AM7/10/16

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I said a couple of posts back I'd submit
a picture of this little interesting thing.
Well here it is.

The bolt isn't the original one but an M5.
Usually there is a bolt which has a very
slightly curved head, then a "boxed shank" and
only then threads. There is nothing to grip but
that is just the beginning of this
bolt's problems.

This type of bolt is now and then found here
and there (for example to hold the rack and
fender stays, an sometimes the saddle pipe
clamp tho then it is much bigger of course) -
anyway those bolts are for some reason almost
always visibly bent! I don't know why but so
far I have replaced them with ordinary hexes...

The nut is the original one which is of the
type that is a combination of a pipe and nut,
the nut part wider as to not fall thru the
hole itself...

http://user.it.uu.se/~embe8573/photos/torpedo-5-speed-pulley.png

Keep it up :)

--
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AMuzi

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Jul 10, 2016, 9:35:51 AM7/10/16

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Any M5 stainless bolt and nut could replace that.

--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971

Emanuel Berg

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Jul 10, 2016, 10:28:23 AM7/10/16

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AMuzi <a...@yellowjersey.org> writes:

> Any M5 stainless bolt and nut could
> replace that.

It remains a mystery why the original ones are
almost invariably slightly bent as there is no
weight on the clamp. Some of those bikes have
been around for decades tho...

AMuzi

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Jul 10, 2016, 10:51:48 AM7/10/16

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On 7/10/2016 9:28 AM, Emanuel Berg wrote:
> AMuzi <a...@yellowjersey.org> writes:
>
>> Any M5 stainless bolt and nut could
>> replace that.
>
> It remains a mystery why the original ones are
> almost invariably slightly bent as there is no
> weight on the clamp. Some of those bikes have
> been around for decades tho...
>

(sorry I top posted. oops)
The faces of teh clamp are not parallel so under torque the
bolt deforms as it's tightened. small problem compared to:

http://seekingalpha.com/news/3192338-report-concern-grows-failure-bolts-used-secure-subsea-oil-wells

bicycle content:
http://www.sfgate.com/news/article/Bolts-along-Bay-Bridge-bike-path-fail-4555354.php

those are one-inch bolts. Then there are the big ones:
http://www.mercurynews.com/ci_23621993/bay-bridges-steel-bolt-failures-reveal-inadequate-metallurgy

John B.

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Jul 10, 2016, 7:28:17 PM7/10/16

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On Sun, 10 Jul 2016 08:51:56 +0200, Emanuel Berg
<embe...@student.uu.se> wrote:

>I said a couple of posts back I'd submit
>a picture of this little interesting thing.
>Well here it is.
>
>The bolt isn't the original one but an M5.
>Usually there is a bolt which has a very
>slightly curved head, then a "boxed shank" and
>only then threads. There is nothing to grip but
>that is just the beginning of this
>bolt's problems.
>
>This type of bolt is now and then found here
>and there (for example to hold the rack and
>fender stays, an sometimes the saddle pipe
>clamp tho then it is much bigger of course) -
>anyway those bolts are for some reason almost
>always visibly bent! I don't know why but so
>far I have replaced them with ordinary hexes...
>
>The nut is the original one which is of the
>type that is a combination of a pipe and nut,
>the nut part wider as to not fall thru the
>hole itself...
>
> http://user.it.uu.se/~embe8573/photos/torpedo-5-speed-pulley.png
>
>Keep it up :)

I've standardized "bicycle bolts" to stainless socket head (allen
head) bolts. The don't rust, they look all right and I only need 4
allen wenches to work on my bicycle. Hardly necessary but I detest
nasty old, rusty screws.

I'm still wondering about the clamp on pulleys. They look like
overkill unless the shift gear has an unusual strong spring.
5,7,9,etc., derailers have used a metal guide for years, apparently
without problems.

--
cheers,

John B.

Emanuel Berg

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Jul 10, 2016, 7:42:06 PM7/10/16

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John B. <slocom...@gmail.xyz> writes:

> I've standardized "bicycle bolts" to
> stainless socket head (allen head) bolts.
> The don't rust, they look all right and
> I only need 4 allen wenches to work on my
> bicycle. Hardly necessary but I detest nasty
> old, rusty screws.

Exactly. Often if you clean the area of the
bolts and nuts and replace them this makes for
a whole new bike.

I also standardize but to hex bolts (M5s
mostly) because they are pull- and holdable
from the sides as well as the front, and this
makes it very seldom they are so entrapped you
have to remove something else to get to them.

> I'm still wondering about the clamp on
> pulleys. They look like overkill unless the
> shift gear has an unusual strong spring.
> 5,7,9,etc., derailers have used a metal guide
> for years, apparently without problems.

You can try pulling the small chain and rod out
of the hub with your hand, this I think
requires more power so the wheels do help.

John B.

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Jul 11, 2016, 1:15:05 AM7/11/16

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I was surprised to read that about bolts holding up bridges.

I had worked mainly for either the Air Force or the Oil Industry and
both are pretty rigorous about specifications. The Oil companies even
specified the thickness of the required paint, coat by coat, on an,
above the ground, pipeline, on one contract.
--
cheers,

John B.