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Selecting An Appropriate Bolt



 
 
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  #31  
Old April 19th 17, 02:17 AM posted to rec.bicycles.tech
external usenet poster
 
Posts: 354
Default Selecting An Appropriate Bolt

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

On Monday, April 17, 2017 at 8:29:53 PM UTC-7, John B Slocomb wrote:
On Mon, 17 Apr 2017 17:51:39 -0400, wrote:

On Mon, 17 Apr 2017 13:52:56 -0700 (PDT), Doug Landau
wrote:

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
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 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?

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=25190411...pp=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=cycl...olt+assortment


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.
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  #32  
Old April 19th 17, 04:04 AM posted to rec.bicycles.tech
John B Slocomb
external usenet poster
 
Posts: 268
Default Selecting An Appropriate Bolt

On Tue, 18 Apr 2017 16:32:48 -0400, wrote:

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

On Tue, 18 Apr 2017 00:08:14 -0400,
wrote:

On Tue, 18 Apr 2017 10:29:32 +0700, John B Slocomb
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 :-)

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)


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....
  #33  
Old April 19th 17, 04:45 AM posted to rec.bicycles.tech
external usenet poster
 
Posts: 354
Default Selecting An Appropriate Bolt

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

On Tue, 18 Apr 2017 16:32:48 -0400, wrote:

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

On Tue, 18 Apr 2017 00:08:14 -0400,
wrote:

On Tue, 18 Apr 2017 10:29:32 +0700, John B Slocomb
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 :-)

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)


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....

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:
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.
  #34  
Old April 19th 17, 12:43 PM posted to rec.bicycles.tech
John B Slocomb
external usenet poster
 
Posts: 268
Default Selecting An Appropriate Bolt

On Tue, 18 Apr 2017 21:17:55 -0400, wrote:

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

On Monday, April 17, 2017 at 8:29:53 PM UTC-7, John B Slocomb wrote:
On Mon, 17 Apr 2017 17:51:39 -0400,
wrote:

On Mon, 17 Apr 2017 13:52:56 -0700 (PDT), Doug Landau
wrote:

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
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 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?

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=25190411...pp=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=cycl...olt+assortment


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)


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.
  #35  
Old April 19th 17, 04:47 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 4,425
Default Selecting An Appropriate Bolt

On 4/18/2017 11:45 PM, wrote:
On Wed, 19 Apr 2017 10:04:13 +0700, John B Slocomb
wrote:

On Tue, 18 Apr 2017 16:32:48 -0400,
wrote:

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

On Tue, 18 Apr 2017 00:08:14 -0400,
wrote:

On Tue, 18 Apr 2017 10:29:32 +0700, John B Slocomb
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 :-)

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)


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....

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:
•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
  #36  
Old April 19th 17, 05:06 PM posted to rec.bicycles.tech
external usenet poster
 
Posts: 1,659
Default Selecting An Appropriate Bolt

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...f3AGoQ_AUIBygC

3ttt traditional:
https://www.google.com/search?q=3ttt...w=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.
  #37  
Old April 19th 17, 05:12 PM posted to rec.bicycles.tech
external usenet poster
 
Posts: 1,659
Default Selecting An Appropriate Bolt

On Monday, April 17, 2017 at 8:29:53 PM UTC-7, John B Slocomb wrote:
On Mon, 17 Apr 2017 16:19:15 -0700 (PDT), Doug Landau
wrote:

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/upl...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 ****ed 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...g&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?


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).


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.
  #38  
Old April 19th 17, 05:23 PM posted to rec.bicycles.tech
AMuzi
external usenet poster
 
Posts: 8,269
Default Selecting An Appropriate Bolt

On 4/19/2017 11:12 AM, wrote:
On Monday, April 17, 2017 at 8:29:53 PM UTC-7, John B Slocomb wrote:
On Mon, 17 Apr 2017 16:19:15 -0700 (PDT), Doug Landau
wrote:

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/upl...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 ****ed 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...g&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?


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).


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.


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.

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


  #39  
Old April 19th 17, 11:23 PM posted to rec.bicycles.tech
external usenet poster
 
Posts: 354
Default Selecting An Appropriate Bolt

On Wed, 19 Apr 2017 18:43:02 +0700, John B Slocomb
wrote:


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)


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.


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.
  #40  
Old April 19th 17, 11:26 PM posted to rec.bicycles.tech
external usenet poster
 
Posts: 354
Default Selecting An Appropriate Bolt

On Wed, 19 Apr 2017 11:47:24 -0400, Frank Krygowski
wrote:

On 4/18/2017 11:45 PM, wrote:
On Wed, 19 Apr 2017 10:04:13 +0700, John B Slocomb
wrote:

On Tue, 18 Apr 2017 16:32:48 -0400,
wrote:

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

On Tue, 18 Apr 2017 00:08:14 -0400,
wrote:

On Tue, 18 Apr 2017 10:29:32 +0700, John B Slocomb
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 :-)

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)

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....

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:
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?

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.
 




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