Selecting An Appropriate Bolt

[Art Shapiro]

I had a bit of an adventure when one of the two handlebar-fixing bolts
on my Deda Murex quilled stem decided to snap with a rather impressive
cracking noise. I somehow didn't crash and happened to be only about
seven miles from home. I got slowly home holding the stem with one hand
and one of the brake levers on the dangling handlebars with the other
hand. (This is not recommended to the reader.)

I see that the bolt is a M6x18 tapered cone head Allen cap screw with
pressed-on washer.

The stem is two months shy of 15 years old, but I don't want to have
this happen again. Looking on eBay, I see quite a few appropriate
bolts, but I'm not sure what is optimal. Can anyone help?

Everything seems to be Grade 5. Is that safe enough, or do I really
want to (somehow) find Grade 8?

Many are titanium. Is that a better choice than the more-common steel?
Or should I look for stainless steel? I am always happy to save a few
grams, but not if that's a significant risk.

Advice welcome!

Art

[John B Slocomb]

Grade 5 bolts should certainly be strong enough to hold the handle
bars on. But there are grades 8 or 9 that are stronger.

As an aside your description is incorrect. It might be an U.S. size
which might be 8-32 or it might be metric in which case it would be
M8-1.25 or maybe M8-1.0. A U.S. #8 bolt is about half the thickness
of a 8mm bolt.

Generally speaking stainless is no stronger than mild steel and
Titanium is about the same strength as steel of the same hardness.
stainless, of course doesn't corrode much and titanium is about half
the weight of steel.

Your description of snapping sounds seems more like something that was
under great tension.... like over torqued?

Again an aside. The bolt(s) broke once in 15 years.....

[AMuzi]

Original handlebar clamp bolts are Grade 8; readily
available and cheap. Grade 5 may be strong enough but for
pennies difference I suggest an 8. I wouldn't use Ti
fasteners in a stem but some guys do and many don't die.

Clean your handlebar, stem and and stem plate. Inspect for
damage/cracks. Clean threads in the stem, inspect for
damage, replace both bolts, lubricate at assembly, ensure
the gap of the handlebar plate is even on both ends. Deda
says torque to 10nm.

Stand in front of your bike and put your full weight on the
brake levers. Handlebar should not move. If it does or if
anything seems awry in any way, replace the stem.


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

[Art Shapiro]

On 4/14/2017 5:35 AM, AMuzi wrote:

> Original handlebar clamp bolts are Grade 8; readily available and cheap.
> Grade 5 may be strong enough but for pennies difference I suggest an 8.

How does one get these "readily available" Grade 8 guys? Deda doesn't
seem to have much of a web presence outside of Italy. Is this a generic
item stocked by a good LBS?

Art

[AMuzi]

Any metric fastener supplier if not your local hardware store.

https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web

[Art Shapiro]

On 4/14/2017 7:27 AM, AMuzi wrote:

> Any metric fastener supplier if not your local hardware store.
>
> https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web
>

Thanks. That search engine link appears to be for traditional cap head
bolts rather than the original tapered cone head bolts. But I'll hit
the drawers at a couple of the area hardware stores or big box stores
and see what they have. Appreciated the input.

Art

[cl...@snyder.on.ca]

The steel bolt may have been "necked down" by rust. Stainless doesn't
do that - but often "welds" itself to the nut - particularly in high
torque installations.

[jbeattie]

On Friday, April 14, 2017 at 7:27:06 AM UTC-7, AMuzi wrote:
> On 4/14/2017 9:14 AM, Art Shapiro wrote:
> > On 4/14/2017 5:35 AM, AMuzi wrote:
> >
> >> Original handlebar clamp bolts are Grade 8; readily
> >> available and cheap.
> >> Grade 5 may be strong enough but for pennies difference I
> >> suggest an 8.
> >
> > How does one get these "readily available" Grade 8 guys?
> > Deda doesn't seem to have much of a web presence outside of
> > Italy. Is this a generic item stocked by a good LBS?
>
>
> Any metric fastener supplier if not your local hardware store.
>
> https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web

My neighborhood hardware store has them: http://aboysupply.com/wp-content/uploads/2014/04/harware_slider1-1024x415_c.png They have a crazy selection of fasteners.

By the way, what's the deal with thread pitch? I always worry I'm getting the wrong pitch, but I guess that the whole "standard/fine/extra fine" thread pitch only kicks in with fasteners over 8mm(?). Otherwise, it's a pre-set. Right?

-- Jay Beattie.

[AMuzi]

There are/were indeed other pitches available (the French
metric m5x0.9 for example) but the DIN standard (m5x0.8,
m6x1 etc) is well established now.

In my experience that's more of a problem with SAE fasteners
(1/4-20, 1/4-28 etc). Prior systems such as AC/AF, UNC/UNF,
Whitworth have become rare and unusual.

[cycl...@gmail.com]

I am horrified that anyone would need a Grade 8 bolt for a stem. I would get a stem that uses two stainless bolts to clamp to the steerer and four to clamp to the bar. I would assume that he is discussing an MTB because I can't imagine conditions bad enough on a road to pop a grade 8 bolt under any forces there.

[Frank Krygowski]

There are metric fine pitch threads
https://mdmetric.com/tech/thddat3.htm
like 5mm-0.5 instead of 5mm-0.8 but I've hardly ever come across them
in real life.

Fine thread fasteners are a bit stronger and more resistant to vibrating
loose. But in most cases, you can solve both problems by other means -
perhaps "next size up" and Loctite.

--
- Frank Krygowski

[Art Shapiro]

On 4/14/2017 10:24 AM, cycl...@gmail.com wrote:

> I am horrified that anyone would need a Grade 8 bolt for a stem. I would get a stem that uses
> two stainless bolts to clamp to the steerer and four to clamp to the bar. I would assume that he is
> discussing an MTB because I can't imagine conditions bad enough on a road to pop a grade 8 bolt under any forces there.

You assume wrong. My Habanero is most assuredly a road bike. And it's
a one-bolt quill stem; I find those cost-reduced threadless stems to be
an ugly atrocity.

I hope to keep the Habanero for a long time; almost everything on it has
been upgraded over the years to full Campy record. The Deda stem, which
I originally sent them to use when constructing the machine, continues
to be a non-Campy exception.

The unexpected failure mode, which could have been catastrophic, was the
reason I posted.

Jay, that's one hell of a hardware store! I've rarely seen that many
specialty drawers.

Art

[jbeattie]

My concern was matching the pitch on threaded bosses -- and most recently wondering whether the 4mm button-head bolts I picked up at the hardware store had the right pitch. For some reason, Specialized decided to use 4mm bolts for the BB/bridge fender mounts on the Roubaix. Very odd. I didn't have any 4mm bolts lying around.

-- Jay Beattie.

[Frank Krygowski]

On 4/14/2017 7:44 PM, jbeattie wrote:
> For some reason, Specialized decided to use 4mm bolts for the BB/bridge fender mounts on the Roubaix. Very odd. I didn't have any 4mm bolts lying around.

That does seem like an odd decision. M5x0.8 has been so normal for so
long. What, were they hoping to save half a gram??

It's like the bicycle industry employs specialists whose job it is to
destroy standardization.


--
- Frank Krygowski

[John B Slocomb]

Or maybe their procurement department got a really, really, great deal
on 4mm bolts -)

What's the old theory? ""Never attribute to malice that which is
adequately explained by stupidity"?

[John B Slocomb]

There are a great number of mail order companies who can supply the
bolts you need. The taper head is a matter of "what looks pretty" and
no not strength. I'm not necessarily recommending them but peruse the
McMaster-Carr web site for available bolts.

Or you could probably contact Andrew Muzi, our resident bicycle parts
specialist :-)

[cycl...@gmail.com]

And I have always found quill stems to be an atrocity.

[Doug Landau]

On Friday, April 14, 2017 at 4:15:34 AM UTC-7, John B Slocomb wrote:
> On Thu, 13 Apr 2017 20:07:48 -0700, Art Shapiro
> <arthur...@cox.net> wrote:
>
> >I had a bit of an adventure when one of the two handlebar-fixing bolts
> >on my Deda Murex quilled stem decided to snap with a rather impressive
> >cracking noise. I somehow didn't crash and happened to be only about
> >seven miles from home. I got slowly home holding the stem with one hand
> >and one of the brake levers on the dangling handlebars with the other
> >hand. (This is not recommended to the reader.)
> >
> >I see that the bolt is a M6x18 tapered cone head Allen cap screw with
> >pressed-on washer.
> >
> >The stem is two months shy of 15 years old, but I don't want to have
> >this happen again. Looking on eBay, I see quite a few appropriate
> >bolts, but I'm not sure what is optimal. Can anyone help?
> >
> >Everything seems to be Grade 5. Is that safe enough, or do I really
> >want to (somehow) find Grade 8?
> >
> >Many are titanium. Is that a better choice than the more-common steel?
> >Or should I look for stainless steel? I am always happy to save a few
> >grams, but not if that's a significant risk.
> >
> >Advice welcome!
> >
> >Art
>
> Grade 5 bolts should certainly be strong enough to hold the handle
> bars on. But there are grades 8 or 9 that are stronger.

What makes you say this? Do you have some #s to back this statement up, or is it just your wild guess? Have you calculated the load on this part when when a rider of a given weight hits a pothole at a given speed, or ??? And more importantly, why skimp here?

> As an aside your description is incorrect. It might be an U.S. size
> which might be 8-32 or it might be metric in which case it would be
> M8-1.25 or maybe M8-1.0. A U.S. #8 bolt is about half the thickness
> of a 8mm bolt.

Huh?!? What are you on about? It is you who is incorrect not he. He said it was an M6x18. The x is pronounced "by". Put M6x18 in google and click images. You will see M6 bolts in an 18mm length. He chose to identify the bolt by it's diameter and length, just like the rest of the world does most of the time.

You are describing bolts using diameter and pitch. This is incomplete, as it does not specify the length. Further is is irrelevant since the JIS and ISO standards both specify 1.0 as the standard pitch for 6mm bolts.

It is not an 8-32, nor is it an 8mm. Both of these suggestions are ridiculous. It is an M6x18 and while fine m6 bolts do exist in 1.10 pitch they are not common and it is safe to say it is, in this application, almost undoubtedly a 1.0. You seem to have latched on the number 8 for some reason.

>
> Generally speaking stainless is no stronger than mild steel and
> Titanium is about the same strength as steel of the same hardness.
> stainless, of course doesn't corrode much and titanium is about half
> the weight of steel.

Steel has or can have greater strength for a given diameter. Why skimp here?

> Again an aside. The bolt(s) broke once in 15 years.....

Looking at it the other way, it already broke once. Furthermore some possible reasons e.g. (e.g. over-tightening) might have also affected the threads that the bolt went into.

>> >The stem is two months shy of 15 years old, but I don't want to have
> >this happen again.

Get a new stem. This one is a flawed design. There is built-in problem with the shape of the part, and that is a lack of remaining metal around the bolt hole. The stem has been made bigger around the front bolt hole to overcome this, but it still has the 2-bolt-1-failure problem. The traditional shape does not make this concession to ease-of-handlebar-change, and carefully places the single bolt in the rear where there is plenty of metal surrounding the threads.
The traditional design is both less likely to experience a bolt failure, and - in the wild guess dept., be more likely to hold on to the bars and remain usable in the event that one does.

Deda Murex 2-bolt:
https://www.google.com/search?q=deda+murex+quill+stem&espv=2&biw=1306&bih=724&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjt0bbaoqzTAhVoyFQKHcf3AGoQ_AUIBygC

3ttt traditional:
https://www.google.com/search?q=3ttt+quill+stem&espv=2&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiY_5-Ho6zTAhWKslQKHYcmCysQ_AUIBygC&biw=1306&bih=724

[cl...@snyder.on.ca]

An M6X10 is the metric "functional equivalent" of a 1/4" UNC bolt.
It's dimensions and strength are very close. Being a metric bolt it
will be neither a Grade 5 nor a Grade 8. - it will be a class 8.8 or
10.9 or 12.9 An 8.8 is the metric "functional equivalent" to a grade 5

[James]

On 18/04/17 07:51, cl...@snyder.on.ca wrote:

> An M6X10 is the metric "functional equivalent" of a 1/4" UNC bolt.
> It's dimensions and strength are very close. Being a metric bolt it
> will be neither a Grade 5 nor a Grade 8. - it will be a class 8.8 or
> 10.9 or 12.9 An 8.8 is the metric "functional equivalent" to a grade 5
>

And of course there are bolts with lesser minimum tensile stress than
800MPa. Class 4.6 for 400MPa, for example.
--
JS

[Doug Landau]

On Friday, April 14, 2017 at 11:11:18 AM UTC-7, Frank Krygowski wrote:

> On 4/14/2017 12:33 PM, jbeattie wrote:
> > On Friday, April 14, 2017 at 7:27:06 AM UTC-7, AMuzi wrote:
> >> On 4/14/2017 9:14 AM, Art Shapiro wrote:
> >>> On 4/14/2017 5:35 AM, AMuzi wrote:
> >>>
> >>>> Original handlebar clamp bolts are Grade 8; readily
> >>>> available and cheap.
> >>>> Grade 5 may be strong enough but for pennies difference I
> >>>> suggest an 8.
> >>>
> >>> How does one get these "readily available" Grade 8 guys?
> >>> Deda doesn't seem to have much of a web presence outside of
> >>> Italy. Is this a generic item stocked by a good LBS?
> >>
> >>
> >> Any metric fastener supplier if not your local hardware store.
> >>
> >> https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web
> >
> > My neighborhood hardware store has them: http://aboysupply.com/wp-content/uploads/2014/04/harware_slider1-1024x415_c.png They have a crazy selection of fasteners.
> >
> > By the way, what's the deal with thread pitch? I always worry I'm getting the wrong pitch, but I guess that the whole "standard/fine/extra fine" thread pitch only kicks in with fasteners over 8mm(?). Otherwise, it's a pre-set. Right?

No. It's just the charts that only kick in at 8. They are clearly both a)written by someone who doesn't actually know, themselves, and b)plagarising heavily from each other, and repeating the other's mistakes.

> There are metric fine pitch threads
> https://mdmetric.com/tech/thddat3.htm
> like 5mm-0.5 instead of 5mm-0.8

That chart is fucked up. It says fine but lists more than one thread pitch in the first column, and inconsistently shows extra- and super-fine pitches instead.

The commonly found standard M5 bolt is indeed 0.8 pitch, but the commonly found fine pitch M5 is 0.7. 0.5 must be extra-fine or super-fine. Which is why when you buy a tap and dies set it comes with 5-.8 and 5-.7 but not 5-.5.
I think but am not 100% sure that M6 fine is 0.8 not 0.75.

http://www.sears.com/craftsman-39-pc-tap-and-die-set-metric/p-00952383000P?sid=IDx01192011x000001&gclid=CLD_kO3LrNMCFQt3fgodoJYAgg&gclsrc=aw.ds

>but I've hardly ever come across them in real life.

No? Are you sure - you've never chased munged up pedal threads? Doing so sends you down to the hardware store for an M10-1.0 tap, because your tap and dies set comes with a 10-1.5 (standard) and 10-1.25 (fine).

There is at least one other place where there is a fine thread, an 8, I think, and I think it's the brake pivot bolt, but am not sure I'm remembering correctly.

What's the thread pitch of derailer hangers?

[AMuzi]

Pedals are 9/16"-20tpi. The older metric format was m14x1.25
(now abandoned) and there are 1/2"-20 for steel OPC.

Modern gear tabs are m10x1. Campagnolo changed from 10f26
(WW 55deg) in 1999.

Sidepull pivot bolts are mostly m6x1.0 but outliers include
Zeus 2001 with fine m6x0.75. There are (were) others but as
I noted they are outliers.

[Doug Landau]

OK, guess i was rembering derailer hangars
http://www.parktool.com/product/frame-tap-tap-10

[Frank Krygowski]

On 4/17/2017 7:19 PM, Doug Landau wrote:
> On Friday, April 14, 2017 at 11:11:18 AM UTC-7, Frank Krygowski wrote:
>>
>> There are metric fine pitch threads
>> https://mdmetric.com/tech/thddat3.htm
>> like 5mm-0.5 instead of 5mm-0.8
>
> That chart is fucked up. It says fine but lists more than one thread pitch in the first column, and inconsistently shows extra- and super-fine pitches instead.

I could have walked downstairs and opened my Machinery's Handbook but
didn't bother. As I said, I've hardly ever come across fine pitch
metric threads in real life. I was simply giving evidence that they exist.

>> but I've hardly ever come across them in real life.
> No? Are you sure - you've never chased munged up pedal threads?

Actually, no, I don't think I ever have.

> Doing so sends you down to the hardware store for an M10-1.0 tap, because your tap and dies set comes with a 10-1.5 (standard) and 10-1.25 (fine).

As Andrew says, my pedal threads are all 9/16", except for some kid bike
steel cranks. Andrew says 20 tpi, and I'll trust him. I've never
bothered to check.

--
- Frank Krygowski

[John B Slocomb]

The "fine thread - course thread" discussion if essentially a very
simplistic categorizing of fasteners. The U.S. Unified thread system
provides a sort of rationalization for a UNC/UNF series but that
didn't and doesn't prevent fasteners being made in a large number of
thread pitches. In U.S. sizes we have, for example, the 1/4"x20tpi
(National Course), the 1/4 x 24 (NS), the 1/4 x 28 (NF), the 1/4 x 32
(NEF) and the 1/4 x 40 (NS).

[John B Slocomb]

You are right. I'll change my reply to read "It might be an U.S. size
which might be 6-32 or it might be metric in which case it would be
M6-1.0. A U.S. #6 bolt is about half the thickness
of a 6mm bolt." Happy now?

>>You are describing bolts using diameter and pitch. This is incomplete, as it does not specify the length. Further is is irrelevant since the JIS and ISO standards both specify 1.0 as the standard pitch for 6mm bolts.

Nope. A thread is described by two things diameter and number of
threads per unit. One can easily buy, for example, a 1/4" thread any
where from a quarter of an inch long, or so, to three feet, or more.

If you want to talk length then yes. A bolt should be long enough that
one complete thread will be extend past the nut. but there is not
maximum length, un less, or course it hits the other side of the
automobile.

>>
>>It is not an 8-32, nor is it an 8mm. Both of these suggestions are ridiculous. It is an M6x18 and while fine m6 bolts do exist in 1.10 pitch they are not common and it is safe to say it is, in this application, almost undoubtedly a 1.0. You seem to have latched on the number 8 for some reason.
>>
> An M6X10 is the metric "functional equivalent" of a 1/4" UNC bolt.
>It's dimensions and strength are very close. Being a metric bolt it
>will be neither a Grade 5 nor a Grade 8. - it will be a class 8.8 or
>10.9 or 12.9 An 8.8 is the metric "functional equivalent" to a grade 5

If you wish to be picky then let us be picky. There is no such thing
as a M6X10 thread, and even if it existed it would hardly be
equivalent to a 1/4-20 bolt. After all a 1 inch 1/4" bolt would have
20 threads on it while your imaginary M6X10 bolt would have only
(roughly) 4. Probably have to tighten the nut real tight to get it to
hold. I wonder can one even cut a 60 degree 10mm thread on a 6 mm rod?

[cl...@snyder.on.ca]

On Tue, 18 Apr 2017 10:29:32 +0700, John B Slocomb
<sloc...@inop.org> wrote:

>
>If you want to talk length then yes. A bolt should be long enough that
>one complete thread will be extend past the nut. but there is not
>maximum length, un less, or course it hits the other side of the
>automobile.

This is not true with AN hardware.AN hardware is spec'd by it's
diameter and grip length -and there is a stringent spec as to how much
thread must/may extend beyond the nut. You NEVER have threads within
the "grip"

>
>>>
>>>It is not an 8-32, nor is it an 8mm. Both of these suggestions are ridiculous. It is an M6x18 and while fine m6 bolts do exist in 1.10 pitch they are not common and it is safe to say it is, in this application, almost undoubtedly a 1.0. You seem to have latched on the number 8 for some reason.
>>>
>> An M6X10 is the metric "functional equivalent" of a 1/4" UNC bolt.
>>It's dimensions and strength are very close. Being a metric bolt it
>>will be neither a Grade 5 nor a Grade 8. - it will be a class 8.8 or
>>10.9 or 12.9 An 8.8 is the metric "functional equivalent" to a grade 5
>
>If you wish to be picky then let us be picky. There is no such thing
>as a M6X10 thread, and even if it existed it would hardly be
>equivalent to a 1/4-20 bolt. After all a 1 inch 1/4" bolt would have
>20 threads on it while your imaginary M6X10 bolt would have only
>(roughly) 4. Probably have to tighten the nut real tight to get it to
>hold. I wonder can one even cut a 60 degree 10mm thread on a 6 mm rod?

Who's being picky??

[John B Slocomb]

On Tue, 18 Apr 2017 00:08:14 -0400, cl...@snyder.on.ca wrote:

>On Tue, 18 Apr 2017 10:29:32 +0700, John B Slocomb
><sloc...@inop.org> wrote:
>
>>
>>If you want to talk length then yes. A bolt should be long enough that
>>one complete thread will be extend past the nut. but there is not
>>maximum length, un less, or course it hits the other side of the
>>automobile.
>
>
>This is not true with AN hardware.AN hardware is spec'd by it's
>diameter and grip length -and there is a stringent spec as to how much
>thread must/may extend beyond the nut. You NEVER have threads within
>the "grip"
>>

Something must have changed with those AN people after the twenty
years I spent fixing their airplanes because the "one thread past the
nut" rule was certainly followed then. I've personally seen an Air
Force Inspector turn down an installation because the bolt didn't
protrude past the nut. (Which is likely why I remember it :-)

[cl...@snyder.on.ca]

On Tue, 18 Apr 2017 18:56:17 +0700, John B Slocomb

You didn't read my whole post Slocumb.

I was responding to the " but there is not

maximum length, un less, or course it hits the other side of the
automobile.

AN bolts need to be the EXACT length required. No more than 2 washers
allowes to adjust the protrusion of the thread through the nut.

If it doesn't protrude OR protrudes too much it fails. (at least here
in Canada)

[Doug Landau]

Nope. Please return to the subject, and change your reply to answer the OP's question, which was "Everything seems to be Grade 5. Is that safe enough, or do I really want to (somehow) find Grade 8?"

This will require first identifying the most extreme condition that the bolt will experience as long as the rider can hold on and stay upright. The goal is to determine safe enough, and one is not going to be safe after riding at cruising speed into a wall or curb anyway. Hitting a pothole seems reasonable to me, but whatever. Then calculate the tension on the bolt in that situation, and then compare that to specification for grade 8.

But what is the value in stating "Grade 5 should certainly be strong enough to hold the bars on." ? So will a rubber band or some scotch tape, as long as one rides slow on smooth road.

>But there are grades 8 or 9 that are stronger

Yes, the OP knows that, and had to to pose the question "Do I need grade 8?" in the first place.

> >>You are describing bolts using diameter and pitch. This is incomplete, as it does not specify the length. Further is is irrelevant since the JIS and ISO standards both specify 1.0 as the standard pitch for 6mm bolts.
>
> Nope. A thread is described by two things diameter and number of
> threads per unit. One can easily buy, for example, a 1/4" thread any
> where from a quarter of an inch long, or so, to three feet, or more.

We are not talking about a thread.

> If you want to talk length then yes.

Again the OP was talking about grade; you faulted him for the way he described the bolt, and I am saying that a)he described it in the same way we all do most of the time, which is not flawed, and b)the quality of this method which you say is a flaw also exists in your claim of what is correct.

The fact is that a bolt has three identifying characteristics, and all must be expressed in order to avoid being incomplete, and at times, insufficient.
Obviously Dorman has already thought this through:
https://www.ebay.com/p/?iid=251904114817&lpid=82&&&ul_noapp=true&chn=ps

> A bolt should be long enough that
> one complete thread will be extend past the nut. but there is not
> maximum length, un less, or course it hits the other side of the
> automobile.

A triple straw man. It's a bike and there is no nut and length is not the issue.

> >>
> > An M6X10 is the metric "functional equivalent" of a 1/4" UNC bolt.
> >It's dimensions and strength are very close. Being a metric bolt it
> >will be neither a Grade 5 nor a Grade 8. - it will be a class 8.8 or
> >10.9 or 12.9 An 8.8 is the metric "functional equivalent" to a grade 5

Another rephrasing of the question, also posed as an answer.

> If you wish to be picky then let us be picky. There is no such thing
> as a M6X10 thread

Noone said there was.

> ...After all a 1 inch 1/4" bolt would have

> 20 threads on it while your imaginary M6X10 bolt would have only
> (roughly) 4.

They are not imaginary; again, M6x10 is the most common way of describing metric bolts. Unlike when describing traditional US sizes, where standard practice is to state either NC/coarse/USS or NF/fine/SAE, metric bolts have a single standard pitch, and so to not state the pitch is not usually ambiguous, despite not being complete.
There are exceptions. The ISO standard pitch for an M8 bolt is 1.25, but the JIS standard is 1.0 (or vice-versa), so when buying M8 bolts for your dirtbike at the hardware store, if it fits in your Yamaha, it is not going to fit in your KTM.
Nevertheless, M6x10 is still by far the most common way of referring to metric bolts, and with a standard pitch of 1.0, an M6x10 bolt will have 10 threads.

https://www.google.com/search?q=cycle+gear+track+pack+bolt+assortment&espv=2&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi6gc7k9a7TAhXoj1QKHcI7CJkQ_AUIBygC&biw=1306&bih=712#tbm=isch&q=+track+pack+bolt+assortment

[cl...@snyder.on.ca]

On Tue, 18 Apr 2017 14:15:09 -0700 (PDT), Doug Landau

Metric thread pitch is described totally different than inch size
bolts. Inch size is threads per inch. Metric thread is thread pitch -
so in inch size bolts, a higher number is a finer thread - in metric a
higher number is a coarser thread. A 6X10 metric bolt is 6mm with a
thread pitch of 1mm crest to crest (or root to root - however you want
to measure it)

As far as the "grade" of the bolt - a "grade 8" is NOT always better
than a "grade 5" or even, possibly, in some cases, a "grade 2"

A grade 2 or grade 5 bolt may bend and stretch - and still hold, where
a grade 8 would simply snap. It depends on what kind of load is being
carried by the bolt - and how it is torqued. On the same vein, a bolt
that is undertorqued CAN fail faster than one that is overtorqued. A
properly tensioned bolt is "pre-stretched" just enough that any cyclic
load does not stretch the bolt any farther, so the bolt does not
fatigue in use.

No use arguing with Slocumb though - you'll never get anything
through his thick skull.

[John B Slocomb]

As I said, for 20 years I fixed my uncles airplanes and I can assure
you that AN nuts and bolts weren't quite as exact as you seem to think
that they are. Certainly one was supposed to not use more than one
washer under the head and the nut but there was no restriction about
how much stuck out of the nut, as long as it was at least one thread.

You are imagining some perfect place where everything is wonderful
when in reality it is 23:30 and a B-52 with two Nukes aboard that
either gets off the ground by 24:00 or it misses its rendezvous and
the aircraft to be relieved won't have sufficient fuel to get home and
another tanker will have to be launched....

[cl...@snyder.on.ca]

On Wed, 19 Apr 2017 10:04:13 +0700, John B Slocomb

I'm just going by the rules I need to follow when building my own
plane up here. The MDRA looks for "good workmanship" and that means
using the right bolts. The bolts come in multiples of 1/8 inch, and
that allows getting the length accurate to within 2 washer thicknesses
(one on each end) with no problem at all. It DOES require having a
good assortment of bolts and washers available though.

The Naval Ship's Technical manual states "A good rule to follow is to
always use the shortest standard length fastener that gives a minimum
one thread protrusion"
From the EAA:
Certain accepted practices prevail concerning the installation of
hardware. A few of these regarding bolt installation follow:
肘n determining proper bolt length - no more than one thread should be
hidden inside the bolt hole.

柊 typical installation includes a bolt, one washer and a nut.
肘f the bolt is too long, a maximum of three washers may be used.
肘f more than three threads are protruding from the nut, the bolt may
be too long and could be bottoming out on the shank.

In Canada the MDRA will flag a bolt with over 3 threads showing on
inspection.

[John B Slocomb]

Who cares, along as the people involved know what you are talking
about? Ant metering system is just that, a system which works for
those that use it.

The old method of measuring gear ratios on a bicycle was to use "gear
inches" which described the diameter of a wheel that would move the
distance in one revolution. Rather archaic today but made perfect
sense to those that used it.

>As far as the "grade" of the bolt - a "grade 8" is NOT always better
>than a "grade 5" or even, possibly, in some cases, a "grade 2"
>
>A grade 2 or grade 5 bolt may bend and stretch - and still hold, where
>a grade 8 would simply snap. It depends on what kind of load is being
>carried by the bolt - and how it is torqued. On the same vein, a bolt
>that is undertorqued CAN fail faster than one that is overtorqued. A
>properly tensioned bolt is "pre-stretched" just enough that any cyclic
>load does not stretch the bolt any farther, so the bolt does not
>fatigue in use.

An exciting theory and technically correct. although I would comment
that I've yet to see an under torque bolt break.

>No use arguing with Slocumb though - you'll never get anything
>through his thick skull.

I served a 4 year apprenticeship and had my papers as a journeyman
machinist in 1950. Was a licensed A&E mechanic two years later (note
in those days it was Aircraft and Engine) joined the Air Force to
avoid being drafted and was in aircraft maintenance for 20 years.

When I retired I went to work in the mining business where that called
me a "Master Mechanic" for some reason.

So yes, I reckon I do know a bit about fasteners, having dealt with
them for 70 years or so. Certainly not everything but probably enough
to tell the difference between a metric and inch thread.

[Frank Krygowski]

> •In determining proper bolt length - no more than one thread should be

> hidden inside the bolt hole.
>

> •A typical installation includes a bolt, one washer and a nut.
> •If the bolt is too long, a maximum of three washers may be used.
> •If more than three threads are protruding from the nut, the bolt may

> be too long and could be bottoming out on the shank.
>
> In Canada the MDRA will flag a bolt with over 3 threads showing on
> inspection.

I don't get it. What's the downside of having an extra thread or two
beyond the nut?


--
- Frank Krygowski

[cycl...@gmail.com]

On Monday, April 17, 2017 at 1:52:58 PM UTC-7, Doug Landau wrote:
>
> >> >The stem is two months shy of 15 years old, but I don't want to have
> > >this happen again.
>
> Get a new stem. This one is a flawed design. There is built-in problem with the shape of the part, and that is a lack of remaining metal around the bolt hole. The stem has been made bigger around the front bolt hole to overcome this, but it still has the 2-bolt-1-failure problem. The traditional shape does not make this concession to ease-of-handlebar-change, and carefully places the single bolt in the rear where there is plenty of metal surrounding the threads.
> The traditional design is both less likely to experience a bolt failure, and - in the wild guess dept., be more likely to hold on to the bars and remain usable in the event that one does.
>
> Deda Murex 2-bolt:
> https://www.google.com/search?q=deda+murex+quill+stem&espv=2&biw=1306&bih=724&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjt0bbaoqzTAhVoyFQKHcf3AGoQ_AUIBygC
>
> 3ttt traditional:
> https://www.google.com/search?q=3ttt+quill+stem&espv=2&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiY_5-Ho6zTAhWKslQKHYcmCysQ_AUIBygC&biw=1306&bih=724

Doug - a stem should NOT be designed in such a manner that it is being held from failing by a bolt. These should be only there to put the parts together and the forces should be held in check by the design of the stem.

Yes, most stems are not so designed but most stems come from China where they don't have to worry about lawsuits from Americans.

A stem should have TWO bolts to tighten it to a steerer only to tighten it from rotating. And two bolts so that one breaking does not disable this capacity. Why on Earth would anyone question that? The handlebar mount likewise should have four bolts on it and the mount should be angled and a step placed in it so that the stem itself is carrying the load of a handlebar and not the bolts that are only there to assemble it.

Old fashioned threaded-head style stems were vastly overbuilt precisely because they were afraid of aluminum. We have more experience and better alloys today and don't have one single angle of stem to pretend racer with.

And those old stems had way oversized stem bolts and still failed because of bolts being given sidewise forces in most of them other than Cinelli who were real engineers.

[cycl...@gmail.com]

On Monday, April 17, 2017 at 8:29:53 PM UTC-7, John B Slocomb wrote:

From memory the difference between American fine and course is the depth of the thread. Course threads cut much deeper into the mating piece to achieve the same amount of metal to metal contact as fine threads.

[AMuzi]

Not just ANC/ANF. Greater depth at coarser pitches is
inherent to a triangular or sine thread form:
http://www.oldengine.org/members/diesel/Tables/form.htm

It's not geometrically inherent to an Acme or similar thread
although those are noted for hefty-load depths.

[cl...@snyder.on.ca]

It's far from "theory" - I've seen numerous head bolts and manifold
bolts fail that were attributed to being under-torqued on vehicles
that were not properly PDId, and quite a few bolts that failed in
shear because they were not properly tightened, and/or the holes were
not properly de-burred, allowing the bolt to loose tension.

>>No use arguing with Slocumb though - you'll never get anything
>>through his thick skull.
>
>I served a 4 year apprenticeship and had my papers as a journeyman
>machinist in 1950. Was a licensed A&E mechanic two years later (note
>in those days it was Aircraft and Engine) joined the Air Force to
>avoid being drafted and was in aircraft maintenance for 20 years.
>
>When I retired I went to work in the mining business where that called
>me a "Master Mechanic" for some reason.
>
>So yes, I reckon I do know a bit about fasteners, having dealt with
>them for 70 years or so. Certainly not everything but probably enough
>to tell the difference between a metric and inch thread.

Some are pretty difficult to differentiate between without having the
wrong bolt for the hole, or the wrong nut for the bolt/stud.

[cl...@snyder.on.ca]

>> 肘n determining proper bolt length - no more than one thread should be

>> hidden inside the bolt hole.
>>

>> 柊 typical installation includes a bolt, one washer and a nut.
>> 肘f the bolt is too long, a maximum of three washers may be used.
>> 肘f more than three threads are protruding from the nut, the bolt may

>> be too long and could be bottoming out on the shank.
>>
>> In Canada the MDRA will flag a bolt with over 3 threads showing on
>> inspection.
>
>I don't get it. What's the downside of having an extra thread or two
>beyond the nut?

With AN hardware there is only a small amount of thread - so if there
is more than 3 threads showing the chances are VERY good that the nut
is bottomed on the thread - therefore to be safe, the next shorter
bolt (1/8" shorter)needs to be installed. Airplane guys are pretty
anal - and for good reason.

[cl...@snyder.on.ca]

The difference is the number of threads per inch - and since the
angle of the threads is all the same that DOES translate ot differeing
thread depths. A 16TPI thread is roughly 1/16" deep for a 100% thread
- while a 32TPI is roughly 1/32 inch deep - because the threads are
closer together.

[John B Slocomb]

You must have a tremendous amount of experience with nuts and bolts.
As I mentioned I've been fooling with them things for about 70 years
now and frankly I've never seen "numerous" head bolts fail. Yes, I've
seen head bolts fail, but I would use the term "rarely" not
"Numerous". I would have to say that if you have seen numerous head
bolts fail then you are associating with some very incompetent
mechanics.

And how does one determine that they were under torqued after they
have failed?

[John B Slocomb]

On Wed, 19 Apr 2017 09:12:06 -0700 (PDT), cycl...@gmail.com wrote:

They are both 60 degree threads but with a flat at the base and peak
and I don't remember whether they are the same. Maybe Frank can check
his Machinery's Handbook (if it is modern enough to include metric
threads :-)

[cl...@snyder.on.ca]

On Thu, 20 Apr 2017 09:52:15 +0700, John B Slocomb

Notb incompetent mechanics - but poor factory assembly.

Don't take my word for the FACT the problem exists.

See: http://www.croberts.com/bolt.htm
In particular Picture #10.

As for broken head bolts - see:
https://www.bimmerforums.com/forum/showthread.php?1741412-Broken-Head-Bolts

Also see: http://www.boltscience.com/pages/Failure%20Modes.swf
and:
https://www.hiretorque.co.uk/failure-modes-of-bolts-and-bolted-joints/
-Particularly item #3
3. Fatigue Failures

Fatigue failures typically occur within a couple of threads, where the
bolt engages into the internal thread. Failure is then reached due to
the high stress gradient within the region.

Fatigue failures can be particularly hazardous because they often
occur with no visible warning signs and the failure is often sudden.
Fatigue failures are often unknowingly avoided in gasketed joints
simply because the required crush for the gasket often dictates a
torque or bolt tension that minimizes the risk of a fatigue failure.
However, changing to a new gasket type later on which requires less
crush may be the initial cause of bolt fatigue failure.

It is not unusual to assume that a bolt has failed due to overload
when it has in fact failed from fatigue, which can also be a
consequence of self-loosening.

Also:
http://www.bluetoad.com/article/Bolt+Fatigue+Failure+Due+To+Insufficient+Tightening/2241311/0/article.html
and:
http://www.onallcylinders.com/2014/03/13/diagnose-common-fastener-failures/

Also:
https://www.excelcalcs.com/engineering-services/engineering-services/why-do-bolted-joints-fail?/
The first cause listed:
Insufficient Clamp force? - Usually by applying a measured torque load
to the nut bolted joints are tightened to achieve a specific clamp
load. Even under the most extreme applied loads, the clamping force
must prevent joint movement between clamped parts. Movement includes
both opening of the joint to form gaps and slipping. Loads applied to
the joint may be axial forces (in the direction of the bolt axis)
and/or shear forces (perpendicular to the bolt axis). If slippage
occurs then the joint may fail by the bolt loosening. If a gap in the
joint opens then a bolt failure by fatigue is more likely to occur.
Typically bolt fatigue failures occur because of insufficient preload
rather than poor fatigue strength of the bolt. Improving the method of
tightening can reduce the scatter in bolt preload and help guarantee
the minimum required clamping force

Pay particular attention to the sectionfollowing the "bolted
joint.xls" link which explains things in pretty plain language.


You may have worked on machines, including aircraft without fully
understanding what you were doing or why.

I have not only worked on cars and agricultural equipment and
industrial equipment (loaders and dozers etc) and been rather
extensively involved with amateur built/homebuilt/experimental
aviation, I have also taught automotive mechanics at the secondary
school AND post secondary (trade) level.

[Frank Krygowski]

On 4/19/2017 6:26 PM, cl...@snyder.on.ca wrote:

> On Wed, 19 Apr 2017 11:47:24 -0400, Frank Krygowski wrote:
>
>>
>> I don't get it. What's the downside of having an extra thread or two
>> beyond the nut?
> With AN hardware there is only a small amount of thread - so if there
> is more than 3 threads showing the chances are VERY good that the nut
> is bottomed on the thread - therefore to be safe, the next shorter
> bolt (1/8" shorter)needs to be installed. Airplane guys are pretty
> anal - and for good reason.

Ah. Got it, thanks.


--
- Frank Krygowski

[Art Shapiro]

On 4/17/2017 1:52 PM, Doug Landau wrote:

> Get a new stem. This one is a flawed design. There is built-in problem with the shape of the part, and that is a lack of remaining metal around the bolt hole. The stem has been made bigger around the front bolt hole to overcome this, but it still has the 2-bolt-1-failure problem. The traditional shape does not make this concession to ease-of-handlebar-change, and carefully places the single bolt in the rear where there is plenty of metal surrounding the threads.
> The traditional design is both less likely to experience a bolt failure, and - in the wild guess dept., be more likely to hold on to the bars and remain usable in the event that one does.
>

I'm he OP. It so happens that the rear bolt was the one that snapped,
which seems to contradict your assertion about the design's weak point.

Art

[John B Slocomb]

You are probably right although the A.F. thought I was competent. Or I
guess that they did as they kept promoting me and they had me managing
divisions for them. Shoot, they even had me writing the skill level
tests for my career field one time.Then when I retired from that job I
hired on as a mechanic again and ended up some years later being
promoted to "Operations Manager" for a fair to middling sized company
in Indonesia.

[John B Slocomb]

And, if I remember correctly, after only 15 years too :-)

[AMuzi]

+1

[cycl...@gmail.com]

Well, I'm just working from a not very good memory but course threads offer less actual bolt area inside of the threads and hence should not be torqued as high as a fine thread.

[cycl...@gmail.com]

That Figure 10 was not a "failure" per se. The bolt did not break from under tightening - it wore the threads off. Eventually indeed it would have broken.

Head bolts on cars can be said to ALWAYS break from over-torquing. What occurs is that you over-torque the head bolts and then when the engine heats up and expands it blows the top of the bolt off from exceeding the mechanical strength of the bolt. Sometimes you can hear it go.

I rarely use a torque wrench because you can FEEL the torque that should be applied and using a torque wrench a number of times shows you that it almost always feels under-torqued. So you develope a feel for it. A correctly designed piece is supposed to use the mechanical strength of a large number of bolts and not the near maximum strength of a few. This is the mistake that is almost always made on that great "German engineering". They use calculations instead of common sense. Ten headbolts torqued within 10% of the proper torque are better than 6 headbolts designed to carry the load if properly torqued to exactly the correct value.

Which reminds me of what is becoming with the carbon fiber engineering these days. It isn't "great engineering" to make a 12 lb bike that can kill it's rider with a single manufacturing flaw.

[AMuzi]

There are cases where an experienced mechanic can torque
properly to within the correct range without a torque
wrench. Unfortunately, there are also times when you thought
you did, but you didn't. On some parts, the result of such
negligence isn't critical, unlike airplanes.

[cl...@snyder.on.ca]

On Thu, 20 Apr 2017 16:17:14 +0700, John B Slocomb

Peter principal at work? It was all "Government work"

[cl...@snyder.on.ca]

No, more head bolts fail from undertorque than overtorque. a properly
preloADED BOLT WILL not SUFFER A FATIGUE FAILURE, WHILE AN
UNDERTORQUED BOLT will EVENTUALLY FAIL DUE TO FATIGUE. iT MIGHT NOT
HAPPEN IN THE NORMAL LIFESPAN OF THE ENGINE - BUT IT will HAPPEN
UNLESS IT IS GROSSLY OVER-SPEC'D

[cl...@snyder.on.ca]

After a few "near misses" at the dealership I started spot checking
wheel torques on vehicles that had wheels removed for service - any
wheel that had been installed with an impact and not checked with a
torque wrench was possible grounds for dismissal.

I also spot checked head torque on new vehicles after PDI.We were paid
to check them. If not checked there washell to pay!

[Sir Ridesalot]

With all ofthe replies about just about everything else, did you get a definitive reply that ANSWERED your question about whether to use a Grade 5 or Grade 8 bolt?

If it were me i'd use the strongest grade I could get.

Cheers

[Frank Krygowski]

I'm with Mr. Clare on all the info above. Those are good sources of
information. This is something we used to cover in great detail in
machine design classes.

--
- Frank Krygowski

[Doug Landau]

I disagree. The traditional design has a single bolt whereas yours has two. Therefore your chances of experiencing a quill stem bolt failure are 2X those of the owner of a traditional quill stem.

Doug

[Doug Landau]

This is false logic. There are at least 15 parts on your bike; by your policy we should expect catastrophic part failure once per year.

[Doug Landau]

> With all ofthe replies about just about everything else, did you get a definitive reply that ANSWERED your question about whether to use a Grade 5 or Grade 8 bolt?
>
> If it were me i'd use the strongest grade I could get.
>
> Cheers

Yes, he did. Andy answered it definitively:

>Original handlebar clamp bolts are Grade 8

What more do you need to know? He then went on to prove it by arriving at the same answer with different logic:

>Grade 5 may be strong enough but for pennies difference I suggest an 8

He and then addressed the Ti question:

>I wouldn't use Ti fasteners in a stem but some guys do and many don't die.

To arrive at this answer via different logic: Speedplay/x2 pedals in Titanium say "Not for riders over 175 Lbs". What else do you need to know? Yes I realize that the pedal shaft is a beam whereas the stem bolt is in tension. So what.

That said, I still want a Habanero.

-dkl

[John B Slocomb]

On the other hand, fine thread bolts having a shallower thread angle
require less torque to obtain the same clamping force :-)

[John B Slocomb]

You are trying to spell "sour grapes" perchance?

[John B Slocomb]

I'm not quite sure what you are trying to say. A bolt that broke after
15 years of use is somehow associated with something that breaks
annually?

[John B Slocomb]

A friend, who was an EWO on B-52's, once commented that it wasn't
exactly confidence building to go to war armed with equipment built by
the lowest bidder :-)

[cl...@snyder.on.ca]

And it depends what you are threading the bolt into. Using fine
threads in coarse grained cast iron is generally NOT a good idea.

As far as the actual "thread area" there is very little difference. If
you double the TPI the threads are only half as deep, but there are
twice as many threads so the total load bearing area is not much
different.

[cl...@snyder.on.ca]

On Fri, 21 Apr 2017 10:21:56 +0700, John B Slocomb

Not a chance!!!! I've worked for enough idiots without having to work
for for politicians and bureaucrats.
Teaching in the public school system was enough politics for me.

Sure, you get a fat pension which I'll have to do without - and I
could have if I'd stayed teaching.

[cl...@snyder.on.ca]

On Fri, 21 Apr 2017 10:21:56 +0700, John B Slocomb

"a loose gaggle of compromises flying in close formation" - which is
why I'm building my own - - -

[James]

Thread area isn't the issue that John brought up.

--
JS

[John B Slocomb]

But one isn't working for a politician when in the service. At least
not when assigned to units that actually have a mission. For example,
I was assigned to one of the two reconnaissance squadrons in the A.F.
equipped with a super long focal length camera. One in Asia and one in
Europe. When you fly missions designated by headquarters USAF they
aren't politicians directing you. I was assigned to the "Gun Ship
Squadron" (puff the magic dragon) where we bragged that if we got
there before they actually got inside the wire we never lost a post.
Not too many politicians there either. Then, lets see, I was assigned
to one of the wings that was flying the SAC airborne nuclear flights,
very serious folks those nuclear chaps, and, oh yes, we provided
support for the U-2 flights over Cuba that told y'all that the
missiles weren't there.

Not many politicians in the operational military (as opposed to the
training units).

>Teaching in the public school system was enough politics for me.
>
>Sure, you get a fat pension which I'll have to do without - and I
>could have if I'd stayed teaching.

Nope, it is rather a thin pension compared to my active duty pay. You
see, what with longevity pay, overseas pay, flight pay, quarters and
rations, etc., active service personnel may draw nearly double their
base salary. When retirement arrives you receive (for 20 years) only
1/2 of your base salary.

[John B Slocomb]

You missed the point. Because fine threads are at a shallower angle
then coarse threads the clamping (linear) force is greater for the
same torque.

[cycl...@gmail.com]

On Thursday, April 20, 2017 at 2:25:50 PM UTC-7, Doug Landau wrote:
>
> This is false logic. There are at least 15 parts on your bike; by your policy we should expect catastrophic part failure once per year.

Because weight is now being stressed over anything else we, unfortunately, can expect at least one catastrophic failures per year.

Though I'm back to steel bikes I had a set of the top of the line Campy aluminum wheels. I did a local ride with a nice 12% climb and strong decent. That is a 40 mph drop. After I got back to town and was about a quarter mile from home a spoke broke on perfectly flat and what passes for smooth road around here. The rim distorted so much I had to carry the bike the remaining quarter mile. If this had happened on that decent... The wheel only had about 3-4,000 miles on it since new.

[cycl...@gmail.com]

On Thursday, April 20, 2017 at 2:39:15 PM UTC-7, Doug Landau wrote:
>
> That said, I still want a Habanero.

You can get them in any grocery store around here.

[AMuzi]

We like Campagnolo wheels generally (within the set of
'modern boxed wheels' they are well above average) but
consider for a moment that a wheel with 36 or 40 spokes may
usually be ridden home with one out but a wheel with 21
spokes usually cannot.

This doesn't make any product good or bad but it's a factor
you might consider when choosing a wheel for a particular
purpose (annual club TT vs 200mi ultra vs following Joerg up
a goatpath, etc)

[cycl...@gmail.com]

That's what I was getting at with the discussion on course and fine threads. If you use course threads the bolt is not as strong as a fine thread because the area of the metal inside of the threads is smaller.

It used to be said that you could tighten fine threads to a higher torque because there was more "leverage" from the fine thread but that isn't the case at all.

So if you are designing a bolt into an iron casting you use course threads but have to use one size larger than you would if it were a finer grain metal and a fine threaded bolt.

Engineering isn't a case of choices as the Germans insist. Designing something to the lightest by making an design to the irreducible minimum while expecting the highest performance is simply asking for troubles. The English are another example. When I had a local mechanic troubleshoot my electrical system to find out why my battery was dying it turned out to be the battery had bitten the dust. It would only hold a charge for a couple of hours. While we were talking he pointed to a Jaguar coupe. That car had a four speed manual transmission that had failed. Anyone knows that manual transmissions do not fail. The replacement cost? $12,000 on a ten year old car. Jaguar would not stand behind their car. If some cheesy plastic part had failed that would be one thing - but manual transmissions DO NOT FAIL. Particularly when it's a little old lady that drives it like she's at Le Mans. She double shifts down better than I can.

[cycl...@gmail.com]

You're talking about Operation Chrome Dome and I went on several of those flights. 24 hours over the north pole isn't a great deal of fun. There isn't hardly any heat or insulation in a B52.

[cycl...@gmail.com]

I have decided that I will buy cyclocross wheels from now on. I can't tell any difference in the looks of the wheels so I suppose they only use larger diameter spokes. But that alone should increase the lifespan of an expensive wheel.

[AMuzi]

Do not fail? Never say never.
I split my MGB first/reverse gear in half racing my neighbor
off a stoplight.
British four manual gearboxes are quite simple devices and
not challenging to rebuild. (or were anyway, don't know new
ones)

[cycl...@gmail.com]

Uhh, they've made a few improvements in steel since the days of the MGB. And my mechanic is the best guy around and if that transmission was rebuildable it would have been rebuilt. You can't rebuild it if it has a split casing or a broken bearing mount. I don't know what the problem was but if Tom couldn't rebuild it it couldn't be rebuilt. He accepts nothing but the best work and the best components.

[Frank Krygowski]

Building your own plane?



--
- Frank Krygowski

[jbeattie]

True CX wheels will use a wider rim, which may or may not be to your taste or tire profile. For your retro bike, just build a set of 32 spoke wheels on ordinary hubs. Use a mid-weight rim like a DT450 (also cheap) or maybe something more aero. 14/15 spokes with brass nipples. My fancy wheels are Dura Ace C35s which have been bomb-proof. Everything else is conventional 32 spoke wheels. I'd go 36 or 40 if I were building a touring wheel. Any high spoke count wheel with conventional spokes can tolerate a broken spoke. I have a spoke wrench on my key chain. If I break a spoke on my commuter, I just adjust the tension, ride home and throw in a new spoke.

-- Jay Beattie.

[Doug Landau]

On Thursday, April 20, 2017 at 8:22:05 PM UTC-7, John B Slocomb wrote:
> On Thu, 20 Apr 2017 14:25:46 -0700 (PDT), Doug Landau
>

Exactly. If your stem fails once in 15yrs, on the average, and so does your seatpost, and so do your bars, forks, and crank, then something will fail every three years.

It is a ridiculously high failure rate.

[John B Slocomb]

There is heating and pressurization in a B-52. The Crews certainly
don't wear the old fleece lined flying clothes that the B-17 and B-24
crews wore :-) And B-52's fly a lot higher (where it is a lot colder).

But I was talking about the possibility of being late with the
launching of one of the relieving aircraft. Not something that any
Wing Commander cared have happen :-)

[John B Slocomb]

Sure, there is a whole bunch of them out there building airplanes in
their garage. Google "home built airplane".

[John B Slocomb]

Why do you equate the failure of one part to the failure of any other
part? Does the fact that the tree in your front yard fell down mean
that your house will fall down? Or that because Joe Boudrou was hit by
a car while crossing the street mean that you can't cross roads as you
are certainly next?

You don't have faulty logic. You have no logic at all.

[Doug Landau]

On Friday, April 21, 2017 at 5:40:37 PM UTC-7, John B Slocomb wrote:
> On Fri, 21 Apr 2017 09:42:35 -0700 (PDT), Doug Landau
>

My logic is perfect. I made no such absolute statements, my statement is prefaced with your 15 year period. You seem impressed with that as an MTBF for an 6mm bolt. I am reminding you that that bolt is not the only such part on the bike, (it has a twin in the seatpost, for example), and so to calculate your average E.T. between scary failures, you must divide that by the # of such parts on the bike.

Viewed in this light, 15 years is an unacceptably high failure rate.

Yes, I am assuming that you would be similarly impressed by a set that failed only once in 15 years, and by such a post, and such fork, and such a bars. Hence the opening "If". Again: IF your stem breaks once in 15 years, AND so does your seat, your post, your forks and bars, THEN, you will have a scary failure once every three years, on the average.

Remember, our friend Jobst died recently from injuries resulting from a frame failure. He had been riding the frame since 1962 or something like that. Now, I'm not saying anything one way or the other about that event. I am not trying to argue that it should have lasted longer, nor, on the other hand, that he shouldn't have ridden it as long as he did. But I think that it provides an interesting reference point.

-dkl

[AMuzi]

Not a frame failure. He hit a pavement barrier while
descending at speed, broke his femur and suffered a
post-surgical stroke.

[cl...@snyder.on.ca]

Didn't miss the point - it was just too obvious to comment on.

[cl...@snyder.on.ca]

And likely the spokes were not tight enough. Low tension spokes WILL
break.

[cl...@snyder.on.ca]

On Fri, 21 Apr 2017 07:08:45 -0700 (PDT), cycl...@gmail.com wrote:

>On Thursday, April 20, 2017 at 11:30:03 PM UTC-7, James wrote:
>> On 21/04/17 13:35, cl...@snyder.on.ca wrote:
>> > On Fri, 21 Apr 2017 10:21:56 +0700, John B Slocomb
>> > <sloc...@inop.org> wrote:
>> >
>>
>> > And it depends what you are threading the bolt into. Using fine
>> > threads in coarse grained cast iron is generally NOT a good idea.
>> >
>> > As far as the actual "thread area" there is very little difference. If
>> > you double the TPI the threads are only half as deep, but there are
>> > twice as many threads so the total load bearing area is not much
>> > different.
>> >
>>
>> Thread area isn't the issue that John brought up.
>
>That's what I was getting at with the discussion on course and fine threads. If you use course threads the bolt is not as strong as a fine thread because the area of the metal inside of the threads is smaller.
>
>It used to be said that you could tighten fine threads to a higher torque because there was more "leverage" from the fine thread but that isn't the case at all.
>
>So if you are designing a bolt into an iron casting you use course threads but have to use one size larger than you would if it were a finer grain metal and a fine threaded bolt.

Basic engineering. also -. Use a grade 8 coarse bolt of the same size
as a grade 5 fine and you are close if there is no contraindication to
use a hard bolt

>
>Engineering isn't a case of choices as the Germans insist. Designing something to the lightest by making an design to the irreducible minimum while expecting the highest performance is simply asking for troubles. The English are another example. When I had a local mechanic troubleshoot my electrical system to find out why my battery was dying it turned out to be the battery had bitten the dust. It would only hold a charge for a couple of hours. While we were talking he pointed to a Jaguar coupe. That car had a four speed manual transmission that had failed. Anyone knows that manual transmissions do not fail. The replacement cost? $12,000 on a ten year old car. Jaguar would not stand behind their car. If some cheesy plastic part had failed that would be one thing - but manual transmissions DO NOT FAIL. Particularly when it's a little old lady that drives it like she's at Le Mans. She double shifts down better than I can.

Manual transmissions DO fail. I've rebuilt many of them over my career
- bad syncros, worn or broken shift forks, bad bearings, broken teeth,
broken drift pins in the shift rails, brunelled gears, and roasting
from running out of oil are the main culprits.

Spread across all brands - Datsun (Nissan) Toyota, Chevy, Ford,
Chrysler, BMC, VW, AMC and Mazda as well as tractors - also trucks as
well as cars - even International Loadstar school busses.

[cl...@snyder.on.ca]

On Fri, 21 Apr 2017 07:11:43 -0700 (PDT), cycl...@gmail.com wrote:


>>

>> Nope, it is rather a thin pension compared to my active duty pay. You
>> see, what with longevity pay, overseas pay, flight pay, quarters and
>> rations, etc., active service personnel may draw nearly double their
>> base salary. When retirement arrives you receive (for 20 years) only
>> 1/2 of your base salary.
>
>You're talking about Operation Chrome Dome and I went on several of those flights. 24 hours over the north pole isn't a great deal of fun. There isn't hardly any heat or insulation in a B52.

Even over the equator at 20,000 feet it's DAMNED COLD!!!

[cl...@snyder.on.ca]

On Fri, 21 Apr 2017 11:25:02 -0400, Frank Krygowski
<frkr...@sbcglobal.net> wrote:

Yup. Rag and tube fuselage, all aluminum flying surfaces - 2 seet
side by side STOL highwing. Power on dirty stall about 18MPH, normal
landing speed about 35MPH - max cruise on 90HP between 100 and 120MPH
- cruise all day at about 85. Land and take off on a football field
without turning around or backtracking. Got a bad cross wind? No
problem - land it ACROSS the runway.

It's called a Pegazair 100.

[cl...@snyder.on.ca]

On Fri, 21 Apr 2017 09:42:35 -0700 (PDT), Doug Landau

No, the whole bike will fall apart every 15 years, so do what most
guys do and replace the bike every 12-14 years - and suffer no major
failures - - - -

[Frank Krygowski]

Very cool project!


--
- Frank Krygowski

[Frank Krygowski]

... unless they were all perfectly designed with precise working lives
of 15 years, as in this classic poem:
http://holyjoe.org/poetry/holmes1.htm


--
- Frank Krygowski

[John B Slocomb]

Well, I guess I was probably aware that the bolt on the stem isn't the
only part on the bicycle, but your assertion that because one bolt
breaks it somehow relates to any, or all, other fasteners, or for that
matter anything else on the bicycle, is certainly not logical.

You seem to be arguing that one bolt somehow relates to all other
bolts and thus a failure of one bolt will be related to possible
failures of other bolts. It doesn't, you know. Bolts are of different
size, different materials, different loads imposed, etc.

As for 15, I'm not sure whether there are 15 bolts on a bicycle. Nope,
I just went out and counted the bolts on my road bike... only 10 :-)

[John B Slocomb]

The "One Horse Shay" was written some years ago :-) But I maintained a
fleet of Datsun pickup trucks at one site that failed in an almost
identical manner. If one major part failed you could be sure that
nearly all other major parts would fail in the immediate future.

Canny people those Japanese :-)

[cl...@snyder.on.ca]

Quite typical of Nissan - possibly due to their alliance with
Renault. I see a lot of good looking Nissans in the wrecking yards
because when they start to fail it's a fast downhill spiral - so a lot
of people scrap them rather than starting to repair them.

Just an observation -

[John B Slocomb]

I suspect that it was the usual Japanese tactic of taking a design
which works and then figuring out how to reduce the cost of making
them without losing the quality (or much of it). The early days of the
35mm cameras is typical. The Japanese started making copies of
European 35mm cameras. Then when the Korean war started the news guys
discovered that they could buy a Nikon, just as good as a Leica, for
half the price.

[cl...@snyder.on.ca]

On Sun, 23 Apr 2017 14:56:53 +0700, John B Slocomb

More likely the french management. Toyota, Mazda, and Honda don't
have that problem. Mitsu deams to - and they have just been taken
under the wing of Renault/Nissan.

[Art Shapiro]

On 4/20/2017 10:18 AM, Sir Ridesalot wrote:

>
> With all ofthe replies about just about everything else, did you get a definitive reply that ANSWERED your question about whether to use a Grade 5 or Grade 8 bolt?
>
Sorry - I hadn't checked the newsgroup in a few days.

I was pretty well convinced to look for a Grade 8. Right now I took the
same bolt from another of the same stem that I had on a previous
bicycle, and am using that for the time being.

ASrt