another grease question: bolt threads

"Abeness" > wrote
> Caroline wrote:
> > Sorry Abeness. At this point I can draw only from my own experience:
Except
> > for spark plugs, anti-seize early and often, then torque to spec
(without
> > adjustment).
>
> Well, I've followed this discussion with interest, and I'm still
> confused. It makes perfect sense to my mind that lubrication would
> affect the amount of torque to apply, because it reduces friction,
> thereby making it easier for the bolt threads to slide on and "pull" the
> threads of the hole (and therefore strip them with less torque). I don't
> know why a bolt would be any different than a spark plug: they both have
> threads, and screw into the engine block--or in this case the tranny
> housing.

They're not. The distinction I was attempting to draw is that this problem
of overtorquing spark plugs arguably is related to the fact that the spark
plug threads are brand new, never been used.

New bolts of any kind will have the same problem, as I'm sure you know,
depending on what is specified re torquing it dry or torquing it with some
kind of lubricant.

> Where is a mechanical engineer when you need one?

Here (to be a total ass), but I flubbed this one. It's not exactly a topic
covered in engineering classes at the undergraduate level. A bit
specialized and more likely something whose detail (e.g. bolt tension) is
more likely to be learned in industry when one is actually required to
design something, liaison with the manufacturers, and then test it. In my
experience. Or that's my pathetic excuse. :-)

Despite my flubbing it, the basic principle (that Tegger first put forth)
should be obvious to most anyone with a bit of hands on experience. A lot
of DIYers talk about the basic idea at their web sites, too. I wasn't
convinced until I came to the comments from GM in the tech article and then
to a site where someone had a lab that could measure bolt tension (not for
the DIYer) and actually did some tests on bolts with and without lube.

Then again, just a few weeks ago torque was discussed in an auto class I
was taking, and while anti-seize was broken out often in the lab, no one
said a word about adjusting the torque to be applied. The instructor was
very competent, too. Maybe he was just a bit rushed.

> I would assume,
> perhaps erroneously, that if Honda specified a drop of oil on the
> crankshaft pulley bolt but not for other bolts, that the torque
> specified for other bolts is that prescribed for non-lubed threads.
> Whether that is teh case or not would be anyone's guess. Perhaps I'll
> try to contact Honda engineering to inquire.

I recently noticed that Chilton's manuals for many American vehicles like
Fords give a range of torque specs. In Honda manuals, a single value is
given.

This might be related to our discussion.

> In the meantime, I suspect I'll do what I usually do in these cases: be
> careful, and sensitive to the "feel" of the situation. Truth is, I can
> tighten the sucker to a reasonable degree, then check it after a few
> days' use and see if it's still tight. If not, I'd tighten it a tad more.

I suspect dealer and independent shop technicians do the same. Torque
wrenches are rarely broken out. Yet cars get repaired, and only once in a
while does one here of a bolt not properly tightened.

"Abeness" > wrote
> Caroline wrote:
> > Sorry Abeness. At this point I can draw only from my own experience:
Except
> > for spark plugs, anti-seize early and often, then torque to spec
(without
> > adjustment).
>
> Well, I've followed this discussion with interest, and I'm still
> confused. It makes perfect sense to my mind that lubrication would
> affect the amount of torque to apply, because it reduces friction,
> thereby making it easier for the bolt threads to slide on and "pull" the
> threads of the hole (and therefore strip them with less torque). I don't
> know why a bolt would be any different than a spark plug: they both have
> threads, and screw into the engine block--or in this case the tranny
> housing.

They're not. The distinction I was attempting to draw is that this problem
of overtorquing spark plugs arguably is related to the fact that the spark
plug threads are brand new, never been used.

New bolts of any kind will have the same problem, as I'm sure you know,
depending on what is specified re torquing it dry or torquing it with some
kind of lubricant.

> Where is a mechanical engineer when you need one?

Here (to be a total ass), but I flubbed this one. It's not exactly a topic
covered in engineering classes at the undergraduate level. A bit
specialized and more likely something whose detail (e.g. bolt tension) is
more likely to be learned in industry when one is actually required to
design something, liaison with the manufacturers, and then test it. In my
experience. Or that's my pathetic excuse. :-)

Despite my flubbing it, the basic principle (that Tegger first put forth)
should be obvious to most anyone with a bit of hands on experience. A lot
of DIYers talk about the basic idea at their web sites, too. I wasn't
convinced until I came to the comments from GM in the tech article and then
to a site where someone had a lab that could measure bolt tension (not for
the DIYer) and actually did some tests on bolts with and without lube.

Then again, just a few weeks ago torque was discussed in an auto class I
was taking, and while anti-seize was broken out often in the lab, no one
said a word about adjusting the torque to be applied. The instructor was
very competent, too. Maybe he was just a bit rushed.

> I would assume,
> perhaps erroneously, that if Honda specified a drop of oil on the
> crankshaft pulley bolt but not for other bolts, that the torque
> specified for other bolts is that prescribed for non-lubed threads.
> Whether that is teh case or not would be anyone's guess. Perhaps I'll
> try to contact Honda engineering to inquire.

I recently noticed that Chilton's manuals for many American vehicles like
Fords give a range of torque specs. In Honda manuals, a single value is
given.

This might be related to our discussion.

> In the meantime, I suspect I'll do what I usually do in these cases: be
> careful, and sensitive to the "feel" of the situation. Truth is, I can
> tighten the sucker to a reasonable degree, then check it after a few
> days' use and see if it's still tight. If not, I'd tighten it a tad more.

I suspect dealer and independent shop technicians do the same. Torque
wrenches are rarely broken out. Yet cars get repaired, and only once in a
while does one here of a bolt not properly tightened.

Caroline wrote:
> The distinction I was attempting to draw is that this problem
> of overtorquing spark plugs arguably is related to the fact that the spark
> plug threads are brand new, never been used.

And because they have been precoated, acc. to the GM quote, presumably
with a lubricant since the quote goes on to refer to the antiseize
compound as "added insurance". I don't know that other types of new
bolts are precoated. But I really know very little about bolts and
threads...

> Here (to be a total ass), but I flubbed this one.

Mistakes happen, few admit them. No "total asshood" witnessed here. I
should've specified "bolt torque expert". ;-))

> to a site where someone had a lab that could measure bolt tension (not for
> the DIYer) and actually did some tests on bolts with and without lube.

Could you post the link? I'd be interested in seeing it myself.

> I suspect dealer and independent shop technicians do the same. Torque
> wrenches are rarely broken out. Yet cars get repaired, and only once in a
> while does one here of a bolt not properly tightened.

Yeah. I've tightened lots of bolts in my day, never used a torque
wrench, and rarely had a problem. I bought a torque wrench for my Honda
work because the aluminum block makes me nervous (had nice solid
gas-guzzling steel blocks previously)--I expect the "feel" will have to
be relearned for aluminum, so I'll go easy at first.

I also wonder what the "wiggle room" is for the Honda torque specs. As
you note, they specify a single value while others specify a range. How
close to max supported torque are those specs? Probably only a Honda
engineer would know.

Caroline wrote:
> The distinction I was attempting to draw is that this problem
> of overtorquing spark plugs arguably is related to the fact that the spark
> plug threads are brand new, never been used.

And because they have been precoated, acc. to the GM quote, presumably
with a lubricant since the quote goes on to refer to the antiseize
compound as "added insurance". I don't know that other types of new
bolts are precoated. But I really know very little about bolts and
threads...

> Here (to be a total ass), but I flubbed this one.

Mistakes happen, few admit them. No "total asshood" witnessed here. I
should've specified "bolt torque expert". ;-))

> to a site where someone had a lab that could measure bolt tension (not for
> the DIYer) and actually did some tests on bolts with and without lube.

Could you post the link? I'd be interested in seeing it myself.

> I suspect dealer and independent shop technicians do the same. Torque
> wrenches are rarely broken out. Yet cars get repaired, and only once in a
> while does one here of a bolt not properly tightened.

Yeah. I've tightened lots of bolts in my day, never used a torque
wrench, and rarely had a problem. I bought a torque wrench for my Honda
work because the aluminum block makes me nervous (had nice solid
gas-guzzling steel blocks previously)--I expect the "feel" will have to
be relearned for aluminum, so I'll go easy at first.

I also wonder what the "wiggle room" is for the Honda torque specs. As
you note, they specify a single value while others specify a range. How
close to max supported torque are those specs? Probably only a Honda
engineer would know.

"Abeness" > wrote
C wrote
> > to a site where someone had a lab that could measure bolt tension (not
for
> > the DIYer) and actually did some tests on bolts with and without lube.
>
> Could you post the link? I'd be interested in seeing it myself.

http://home.att.net/~benmlee/threads/threads.htm

I'm not a fan of reports on personal web sites, but this guy's direct,
hands-on experience (with spacecraft fastener testing) applied to this
little study impressed me.

> > I suspect dealer and independent shop technicians do the same. Torque
> > wrenches are rarely broken out. Yet cars get repaired, and only once in
a
> > while does one here of a bolt not properly tightened.
>
> Yeah. I've tightened lots of bolts in my day, never used a torque
> wrench, and rarely had a problem. I bought a torque wrench for my Honda
> work because the aluminum block makes me nervous (had nice solid
> gas-guzzling steel blocks previously)--I expect the "feel" will have to
> be relearned for aluminum, so I'll go easy at first.

The valve cover was a big impetus for me to buy a torque wrench.

Otherwise, like you, until recently most of my car work has been without a
torque wrench. Work in industry was a mixed bag. Nuclear: Shucks yes.
Non-nuclear: Time is money.

> I also wonder what the "wiggle room" is for the Honda torque specs. As
> you note, they specify a single value while others specify a range. How
> close to max supported torque are those specs? Probably only a Honda
> engineer would know.

Have you noticed the front section of many Chilton manuals talks about
torques and gives a table of recommended torque ranges for different sized
bolts as a guideline? Which can be found on the Internet at various sites,
too. E.g. at Autozone for 1984-1995 Civics under "Tools and Equipment":
Bolts marked 6T
6mm bolt/nut: 5-7 ft. lbs.
8mm bolt/nut: 12-17 ft. lbs.
10mm bolt/nut: 23-34 ft. lbs.
12mm bolt/nut: 41-59 ft. lbs.
14mm bolt/nut: 56-76 ft. lbs.

Like you said, the stuff of bolt specialists.

Also, I for one try not to assume too much when I apply bolt specs. After
all, rarely am I working with brand new bolts. What the rust, general
deformation of threads, etc. do to bolt tension for a given torque over
time involves I think consideration of

1. Using antiseize on older bolts that display minor galling.
2. Replacing really old bolts (having worn threads)
3. Torquing to lower end of spec, or possibly reduce the torque spec "some"
amount, when using anti-seize on newer bolts.
4. God knows what temperature changes do to the whole calculation. (Well,
we have some idea: Bolts stretch as they're heated and so tend to loosen.)

"Abeness" > wrote
C wrote
> > to a site where someone had a lab that could measure bolt tension (not
for
> > the DIYer) and actually did some tests on bolts with and without lube.
>
> Could you post the link? I'd be interested in seeing it myself.

http://home.att.net/~benmlee/threads/threads.htm

I'm not a fan of reports on personal web sites, but this guy's direct,
hands-on experience (with spacecraft fastener testing) applied to this
little study impressed me.

> > I suspect dealer and independent shop technicians do the same. Torque
> > wrenches are rarely broken out. Yet cars get repaired, and only once in
a
> > while does one here of a bolt not properly tightened.
>
> Yeah. I've tightened lots of bolts in my day, never used a torque
> wrench, and rarely had a problem. I bought a torque wrench for my Honda
> work because the aluminum block makes me nervous (had nice solid
> gas-guzzling steel blocks previously)--I expect the "feel" will have to
> be relearned for aluminum, so I'll go easy at first.

The valve cover was a big impetus for me to buy a torque wrench.

Otherwise, like you, until recently most of my car work has been without a
torque wrench. Work in industry was a mixed bag. Nuclear: Shucks yes.
Non-nuclear: Time is money.

> I also wonder what the "wiggle room" is for the Honda torque specs. As
> you note, they specify a single value while others specify a range. How
> close to max supported torque are those specs? Probably only a Honda
> engineer would know.

Have you noticed the front section of many Chilton manuals talks about
torques and gives a table of recommended torque ranges for different sized
bolts as a guideline? Which can be found on the Internet at various sites,
too. E.g. at Autozone for 1984-1995 Civics under "Tools and Equipment":
Bolts marked 6T
6mm bolt/nut: 5-7 ft. lbs.
8mm bolt/nut: 12-17 ft. lbs.
10mm bolt/nut: 23-34 ft. lbs.
12mm bolt/nut: 41-59 ft. lbs.
14mm bolt/nut: 56-76 ft. lbs.

Like you said, the stuff of bolt specialists.

Also, I for one try not to assume too much when I apply bolt specs. After
all, rarely am I working with brand new bolts. What the rust, general
deformation of threads, etc. do to bolt tension for a given torque over
time involves I think consideration of

1. Using antiseize on older bolts that display minor galling.
2. Replacing really old bolts (having worn threads)
3. Torquing to lower end of spec, or possibly reduce the torque spec "some"
amount, when using anti-seize on newer bolts.
4. God knows what temperature changes do to the whole calculation. (Well,
we have some idea: Bolts stretch as they're heated and so tend to loosen.)

Caroline wrote:
> Otherwise, like you, until recently most of my car work has been without a
> torque wrench. Work in industry was a mixed bag. Nuclear: Shucks yes.

I wonder why...

> Have you noticed the front section of many Chilton manuals talks about
> torques and gives a table of recommended torque ranges for different sized
> bolts as a guideline?

I've never paid much attention to bolt torques, for reasons described
previously, so no. I went right to the Helm manual for my Honda, skipped
Chilton's/Haynes entirely after some reports of errors, and I wanted the
full monty.

> Also, I for one try not to assume too much when I apply bolt specs.

A wise practice. Thanks for the link.

Caroline wrote:
> Otherwise, like you, until recently most of my car work has been without a
> torque wrench. Work in industry was a mixed bag. Nuclear: Shucks yes.

I wonder why...

> Have you noticed the front section of many Chilton manuals talks about
> torques and gives a table of recommended torque ranges for different sized
> bolts as a guideline?

I've never paid much attention to bolt torques, for reasons described
previously, so no. I went right to the Helm manual for my Honda, skipped
Chilton's/Haynes entirely after some reports of errors, and I wanted the
full monty.

> Also, I for one try not to assume too much when I apply bolt specs.

A wise practice. Thanks for the link.

"TeGGer®" > wrote
> "Caroline" > sprach
> > I suspect dealer and independent shop technicians do the same. Torque
> > wrenches are rarely broken out. Yet cars get repaired, and only once
> > in a while does one here of a bolt not properly tightened.
>
> That's because they tighten until it "feels right". It's learned by
> experience.

I believe this "experience" of which you speak has no relation to actually
testing the feel of, say, 26 ft-lbs. of torque. Instead, it's "Feels tight.
Must be right." I have a vague recollection of a study that showed what
numerical torque people hoped to achieve and what they actually achieved
were widely different.

One data point: The many anecdotes about lug nuts not torqued to spec, but
to what the operator felt was right, and the warped rotor etc. outcomes of
this.

Sorry, but I had a chance to watch a gaggle of shadetree mechanics
(self-decribed "experts") over the course of several weeks not long ago,
and watching them wrap their ego around their wrong-headedness was
fascinating.

(For the record, I don't find a shadetree mechanic approach here at the
group, for the most part. And yup, I still find the typical, say five years
of experience, shadetree mechanic smarter than an MD. Which is a comment on
doctors... ;-) )

> I do the same with anything I can't get a torque wrench

Yup. And I don't lose sleep over it when I do. But this is after years of
experience.

OTOH, who here with 20 years experience with tightening bolts has never
stripped one or sheared off a head? Or had one come loose?

> on or if I don't
> know what the torque should be.

These days when this happens I use the various tables available for
automotive fasteners.

"TeGGer®" > wrote
> "Caroline" > sprach
> > I suspect dealer and independent shop technicians do the same. Torque
> > wrenches are rarely broken out. Yet cars get repaired, and only once
> > in a while does one here of a bolt not properly tightened.
>
> That's because they tighten until it "feels right". It's learned by
> experience.

I believe this "experience" of which you speak has no relation to actually
testing the feel of, say, 26 ft-lbs. of torque. Instead, it's "Feels tight.
Must be right." I have a vague recollection of a study that showed what
numerical torque people hoped to achieve and what they actually achieved
were widely different.

One data point: The many anecdotes about lug nuts not torqued to spec, but
to what the operator felt was right, and the warped rotor etc. outcomes of
this.

Sorry, but I had a chance to watch a gaggle of shadetree mechanics
(self-decribed "experts") over the course of several weeks not long ago,
and watching them wrap their ego around their wrong-headedness was
fascinating.

(For the record, I don't find a shadetree mechanic approach here at the
group, for the most part. And yup, I still find the typical, say five years
of experience, shadetree mechanic smarter than an MD. Which is a comment on
doctors... ;-) )

> I do the same with anything I can't get a torque wrench

Yup. And I don't lose sleep over it when I do. But this is after years of
experience.

OTOH, who here with 20 years experience with tightening bolts has never
stripped one or sheared off a head? Or had one come loose?

> on or if I don't
> know what the torque should be.

These days when this happens I use the various tables available for
automotive fasteners.