to change a Honda Accord 1988 model timing belt

I don't agree. Using a torque wrench as you describe puts a lot more wear
and tear on it for each assessment of a bolt's loosening torque (as opposed
to the one-time application of tightening torque). The wrench "allows" only
so many clicks before calibration becomes a concern.

Without good calibration, the torque wrench is useless.

Off the top of my head, I would say the removal torque probably varies more
at higher axial loads than lower axial loads. That is, if one takes several
measurements of loosening torque at a given lower axial load, this
collection of "low load removal torques" will have a lower standard
deviation than that of a corresponding collection of "high load removal
torques."

The thread mating surfaces are closer together at higher axial loads. So
static (as opposed to dynamic) friction effects should prevail increasingly
more the closer one gets to the maximum allowable axial load in the bolt. In
addition, surface conditions can vary a lot due to wear, how lubricant was
applied, temperature, even the manner in which the bolt was tightened. The
variability of surface conditions from one tightening to the next should
increase the unpredictability of loosening torque at higher axial loads.

By contrast, at lower loads, the thread mating surfaces are farther apart,
so the mating surfaces' condition should have less of an effect on the
friction between them. Below a certain axial load, it's more likely to be,
say, oil molecules sliding over oil molecules. Whereas at higher loads, one
can't say with as much certainty whether it's oil sliding over oil or steel
sliding over steel, with imperfections in the steel and wear in the threads
at work as well.

Otherwise, if your car were just for lab experiments, I would be tempted to
repeat the experiment with a torque wrench of reasonably-well known
calibration. This sounds fishy, like those guys are abusing their highly
sensitive torque wrenches, to me.

Regardless, yours is a good example of why folks should probably do their
own torquing of their lug nuts, even after they've been torqued at the shop.

 

of course. not only is it specified by the manufacturer, but more
importantly, their liability insurance /requires/ they use torque
wrenches. i used to date an accident/injury attorney, and she used to
/nail/ poor sob's who couldn't prove they'd used such practices.

right side or left side?

with respect, that's straw clutching. go to a parking lot where there
are some big rigs and look at their wheel lugs. see any where there are
red rust marks around the nut, particularly ones where the red has
streaked radially outwards? that's fretting at the interface, and
fretting is movement. if there's movement, there's precession [in
lateral loading] and it will either loosen or tighten, depending on the
sense of rotation relative to the thread. you think your car lugs were
tight? try a nice red-rusted big rig lug nut some time.

why don't left side car lugs loosen? because they have a tapered
interface, and as you know, tapers impart significantly higher friction.
this will prevent rotation if torqued sufficiently. which brings us
neatly back to accident/injury attorneys and liability insurance...

 

And how often am I going to do this? Every week? I did this with 16 wheel
nuts on one occasion.

There is absolutely nothing wrong with using the wrench as I did. Remember
that torque wrenches are meant to be used on an hourly basis. Garages use
the same wrench every few minutes.

What they refer to in the warning is that some people try to use torque
wrenches as breaker bars, since they are long and provide lots of leverage.
In use, the wrench's maximum torque can thereby get drastically exceeded.


<snip>

There is no gap between mating threads when the bolt is tight, no matter
how much/little tension is present.

When the bolt's threads ride up the incline, the threads are squeezed
together with more pressure as tension on the bolt's shank increases, but
the the threads can not get any /closer/ together.

"Embedment" after final tightening torque DOES occur, and results in a
reduction in bolt tension (not the same as torque!) of about 5-10%.

 

Most torque wrenches are designed to measure dynamic torque accurately, not
static.
Is yours different?

 

Wow. You do dig in.

I am happy to agree to disagree.

I am confident that garage torque wrenches tend to be far more out of
calibration than the average home DIYer.

If you think differently, whatever.

The number of clicks counts.

The bolt threads and female side threads are perfect, eh.

We disagree.

It's not so black and white, like an "on/off" situation.

But you believe what you want. I gave you a theory that supports your idea.
Throw it out. I don't care.

 

There is only one click.

 

The torque wrench has only about so many clicks in its life before its
calibration becomes too far off to be useful.

Your measurement of breakloose torque requires several clicks per
measurement.

 

There is only ONE click.

You've never actually used a click-type torque wrench.

 

You proceeded in 2 ft-lb increments. Are you saying you don't let it click
after each increment.

Right. And I lie about my 91 Civic averaging 40+ mpg. And I lied about Grade
8 bolts being available at popular hardware stores. And what I said (with
others) about clogged PCV valves reducing fuel mileage is a lie, too.

All these things you said were lies, and you were shown wrong.

Torque wrenches do not stay calibrated forever. One crude measure of when
one requires calibration is how many clicks it's seen.

 

Of course I did. Tht's the only way I knew it passed that figure without
breaking loose.

After the click, you can keep turning if you like, and the wrnch will apply
torque to the bolt, but that would be pretty stupid.

<snip>

Well, have you?

 

come on kids, play nice or don't play at all.

actually, it's not that crude. clicking torque wrenches that get
regularly used in factory assembly work get recalibrated based on usage.

 

Of course. I own two click torque wrenches (one high range; one low range)
and have mentioned them several times here.

We're probably having a miscommunication. You posted that you attempted to
estimate the breakloose torque of a wheel lugnut by using your torque wrench
on a lugnut you originally tightened to IIRC 75 ft-lbs. You set the torque
wrench (in reverse; flipped the lever on the head, probably) to I presume
something like 73 ft-lbs. the first time. The "click" was heard, whence you
raised the setting to 75 ft-lbs. The "click" was heard whence you raised it
to 77 ft-lbs. Etc. until you got to a setting of 90 ft-lbs. The lugnut
loosened, and no click was heard.

That's a buncha "clicks" to get to the 90 ft-lbs whence the bolt finally
loosened.

 

Son, you should have called out Tegger. He is in the habit of insisting
someone is lying when he doesn't understand something posted. Indeed, one of
your posts tonight shows your own irritation with his saying as much of one
of your claims.

Noted.

 

kid_S_ is plural. that means BOTH of you.

 

Sorry, Jim, but you're not being fair. You too called out Tegger for saying
you were lying in a post tonight. It's a bad habit of his. He needs a bit of
patience and tenacity in ensuring he understands what's being said. Though
he'll likely never give in on the PCV valve matter. Which I note time and
again you don't call him out on. But you're quick to call me out if I post
something erroneous. I on the other hand look the other way at your really
poorly thought-out theory re precesssion. It is not happening. You've
confused "precession" with something much simpler: Shaft turns. Bolt doesn't
turn as quickly. Relative motion occurs between the two. Bolt tightens. In
theory. <shrug>

"Son" is singular. That means you are behaving like a child along with
Tegger.

Some time someone will mark their pulley bolt and pulley and report back on
relative motion (and I have in mind more than the angular lash of the key).
There may not be any. Yet there may be. Dunno. I am not satisfied that
galling, aggravated by heat cycling, is the only thing at work here. But it
could be. That's the difference between Tegger's and my approach, so far.

I return to our regularly scheduled programming, after the usual flames in
retort.

 

Elle wrote:

who cares? i'm just sick of the pair of you squabbling. if you think
i'm somehow singling you out for special attention, you're mistaken -
you just happened to be at the end of the thread when i got home and
chose to reply. you are /way/ too ready to wear that "victim" teeshirt
your daddy gave you.

 

Evidently you do.

I'm sick of Tegger calling people liars. I'm sick of him asserting diagnoses
as fact rather than a best guess.

You're consistent in this habit.

This is the ready defense of someone who disputes the evidence of prejudice
in the world and practices it himself. <shrug>

You're still wrong about the precession. Way wrong.

 

Apologies.

I misinterpreted what you meant when you said "number of clicks matters".

Of course you're right, they do. But that's independent of what you do with
the wrench so long as you're not overloading it.

This is why torque wrench calibration services exist. You're supposed to
get them recalibrated once in a while to compensate for normal wear.

 

Time for a little anecdotal insertion.

When I was responsible for calibrating torque wrenches on a hi-tech
production floor, one of the engineers related how when he worked at
Boeing Aircraft, all torque wrenches were calibrated twice per shift.
He also added, based on his experience of how much each type of
torque wrench was out of spec when calibrated, micrometer-click torque
wrenches were the worst for maintaining correct torque settings.
Second were dial-type wrenches, with beam torque wrenches being the
most consistently accurate.

My company used click style wrenches which were calibrated once per
use (several days between use). But, they were the single setting
type, one torque setting per wrench. This because micrometer adjust
torque wrenches work over such a wide range, they were not accurate
enough for our needs. Click type wrenches work on a spring and detent
arrangement. The spring grows weaker with time and use and the detent
wears. This degradation of components requires constant recalibration
to be accurate. You start tossing in repeated adjustments up and down
a 50-75 ft/lb range and accuracy is a crap shoot.

nb

 

Guess I'd better get mine done soon.