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Old April 30th 17, 07:47 PM posted to rec.bicycles.tech
AMuzi
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Posts: 13,447
Default torque wrench issues

On 4/30/2017 12:01 PM, Ian Field wrote:


wrote in message
...
On Sat, 29 Apr 2017 19:53:16 +0100, "Ian Field"
wrote:



wrote in message
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On Tue, 25 Apr 2017 20:16:22 +0100, "Benderthe.evilrobot"
wrote:


"John B Slocomb" wrote in message
...
On Mon, 24 Apr 2017 22:17:14 -0400,
wrote:

On Tue, 25 Apr 2017 07:42:21 +0700, John B Slocomb
wrote:

On Mon, 24 Apr 2017 19:51:41 +0100,
"Benderthe.evilrobot"
wrote:


wrote in message
...
On Sun, 23 Apr 2017 22:06:05 +0100,
"Benderthe.evilrobot"
wrote:


"Emanuel Berg" wrote in message
...
I finally got the 1/2" torque wrench,
28-210 Nm, not even made in China, but in
Taiwan! Eh... I guess it depends who you ask if
that is China or not

It has a locking screw, a torque setting
handle, a scale (Nm as well as "FT-LB", some
English unit I take it?) - it also as a
locking lever on top just like an ordinary
ratchet, so it can go both ways, clockwise and
anti-clockwise.

The torques only work in the
clockwise direction. So if the
locking (ratchet) lever is set the other way,
it is just a ratchet, right? Well, in
the manual it says:

Note: Never use the torque wrench to undo
nuts, bolts or other fasteners as this will
damage the ratchet mechanism and the
calibrated settings.

So how does that add up? Is it only OK to use
the anti-clockwise pull to insert things, which
would require a left thread? (And it would be
just a long shaft, with the torque not
in effect.)

As for me, I don't plan using it for anything
but as a torque, because I have other, less
expensive ratchets and spanners to do the
everyday stuff. But of course, I'd like to know
what it means.

It also came with a certificate with data on
the calibration and in the manual it says it
should be recalibrated at least every
12 months.

Calibration is irrelevant if you don't follow the
rules to the
letter.

Most torque settings I've seen were for dry
threads - any stray
lubricant
and you might even twist the end off at the
correct torque.


---
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Torque specs vary considerably by application.
Some are given as
clean and dry, some are given as lubricated with
oil - some are
given
cold, and others hot. That said, I personally have
never run across
a
torque spec that was so "close to the edge" that
torqing with "stray
lubrication" would cause immediate failure of the
bolt by twisting
off
the end.
However, that said, most of my wrenching has not
been on bicycles
but
on automobiles and agricultural and construction
equipment which may
be slightly more "overengineered" or "overbuilt"

Bicycles tend to have less things you can twist the
end off.

Its common on motorcycles, but mainly pulling the
threads out of alloy
castings. Its pretty rare to strip an engine down
so far that you can
put
the castings in degreasing plant - torquing the
engine case bolts with
oil
left in the holes is a very good chance of
stripping the threads.

As for stripping engine bolts, the Honda factory
used to install
fasteners so tight that a normal person couldn't get
them out without
an"impact driver". A tool that I never even saw
before the Japanese
invasion.

The lock washers were very effective where used, and
the Phipips style
bolts were incapable of delivering enough torque to
breat them loose
without camming out - the Hammer Impact driver solved
that problem

I believe I've read that the "Phillips" headed screws
in a Japanese
motorcycle are not actually "Phillips" but some
Japanese standard that
didn't quite match the screwdrivers we had in the U.S.
Which probably
didn't help either :-)

That's the *whole* cause - just grind a tiny bit off
the point of the
screwdriver bit and it fits just right.
The bits on my Impact driver fit perfectly without
grinding.
Note I said Philips "style" (I know, I mis-spelled it)
bolts.
Some of the early Jap stuff didn't use Cadmium plated
bolts either -

W10 imploded and I had to start over with a replacement
news account. So
back to old name.

The japs were the worst of the lot for cadmium plated
fasteners.

The very toxic cadmium rubs off on your hands and is
cumulative in the
body - it causes such acute osteoporosis; you can end up
fracturing ribs
just by coughing.

In the UK - nickel plated fasteners became fashionable
about the 80s. They
didn't do much about cadmium plated chassis in electronic
equipment until
RoHS.

AFAIK: cadmium batteries are exempt from RoHS - but
they've more or less
vanished from the shops anyway.

Cadmium is very nasty - wash your hands after handling
anything plated with
it!


from Cadmium, A Health Hazard Surface Treatment
C. Rehm
ESG
Einsteinstr. 174
D-81675 Munich, Germany

An object containing cadmium is not especially injurious
to health on
its own. No risk is involved simply by touching it.
A potential hazard occurs, however, when such objects are
processed
and high temperatures are generated.


Cadmium plating rubs off on your hands whenever you handle
cadmium plated parts and assemblies.

Many years ago they even used it on electronic component
leads to prevent oxidation - they used more aggressive
fluxes in those days.

Welding cad plated sheet steel is particularly dangerous -
the cadmium is vapourised and becomes airborne.

Usually the osteoporosis takes decades to start crippling
the sufferer - but I've heard of a repair technician
dropping dead after a couple of years from fumes using low
melting point cadmium based solder. The specific mode of
death wasn't announced.

The Japanese know all about it, they discharged industrial
effluent containing cadmium into heavily fished costal
waters. They even have a name for the disease - itai itai
byo. apparently its the noise sufferers make in their death
throes. As I mentioned previously - bones become so weak and
brittle, you can fracture ribs just by coughing.


Well then avoid it as you wish.

Many of us recognize the difference between metals and
reactive metallic organic compounds.

Zinc rich tablets are popular for symptoms of herpes simplex
and yet no one welds galvanize steel a second time.

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


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