Bicycle DRLs - Actually reading the paper, actually looking at the

On 7/18/2015 8:21 AM, Frank Krygowski wrote:
On 7/18/2015 8:10 AM, John B. Slocomb wrote:


I seriously doubt that drilling a small hole in a frame
tube is going
to cause any problems, but perhaps we can have Frank do a
stress
analysis on a Columbus "Airplane" Aluminum down tube.
Triple butted
2.2-1.0-1.4. Tensile strength 420 mPa or ~61,000 psi. Say
a 5/16"
hole.

Calculation doesn't do much for a situation like this. Any
detrimental effects of drilling a hole depend greatly on the
stress situation the part is subjected to. And of course,
the design of a Rivnut is intended to reinforce the hole
that's been drilled. I think that's beyond the reach of
classical math.

One guy I knew had been (in days of yore) an expert on
theoretical calculations of stress concentration factors,
using some really high-powered mathematics, and even then it
was limited to rather simple cases - a plate in uniform
tension, for example. But these days that sort of stuff is
done by finite element analysis, and is extremely specific
to the case at hand.

I think we gain more from examining the results of
experience. The fact that Rivnuts are used so successfully
in so many applications speaks in their favor - even though
Scharf or Joerg are bound to present us with one failure as
"proof" that they're worthless.


I don't know either.

But with a large and long experience around failed bicycle
frames, I can't recall ever seeing a failure emanating from
a water bottle hole, brazed or rivnutted. I've seen
customer-tapped bottle holes in 1.0 or 1.2mm tube which,
while not a great idea, served well for years without incident.

Cyclic and torsional (non-impact) failures seem to almost
exclusively[1] concentrate at the joints (various jointing
techniques). Impact failures can be just about anywhere, and
are.

[1]notable anomalies include a seamed-tube welded seam which
opened despite the alleged "Reynolds 531" frame label.
--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On 7/18/2015 4:33 AM, Duane wrote:

True. In my case I have 2 bikes. One is CF and won't be drilled at all.
The other is a 93 crop moly steel lugged bianchi that's too nice too be
drilled. So I have no interest either way.

Besides being a poor idea to drill either, there's no need to. You can
get a much stronger cage mount without the downsides by using one of
many accessories designed for this. You distribute the load all around
the frame tubing.

Here's a good discussion on the subject where Jobst concurs that it's a
bad idea to drill a frame for Rivnuts:
http://yarchive.net/bike/rivnuts.html. Yeah, some people do it anyway
and nothing bad happens and they proclaim that that's "proof" that it
was a good idea, but most people have better critical thinking skills
than that.

One other thing I noticed recently is that there are a lot of pretty
heavy things that use standard bottle cage mountings. You definitely
would not want to use these devices on a bicycle frame where Rivnuts
were used.

BTW, here is the section on Rivnuts from my web site on cage mounting
solutions at http://nordicgroup.us/cageboss/:

-----------------

A Word About Rivnuts

A properly installed Rivnut does not exert any stress on the inner and
outer walls of the tubing. The stress all radiates outward from the
splines of the Rivnut into the circumference of the hole.The friction
between the splines of the Rivnut and the hole keep it from rotating.

Recently, one person became very upset at my statement about Rivnuts. He
correctly points out that Rivnuts are used by many aluminum frame
manufacturers, at the factory, for bottle cage bosses. So why shouldn't
it be okay to grab an electric drill, drill some holes in a frame, and
insert some Rivnuts? The reason is because a frame manufacturer using
Rivnuts on a frame at the time it is manufactured is very different than
an end user drilling holes in their complete bicycle and trying to
properly insert Rivnuts themselves.

Here are the differences:

1. The frame manufacturer is able to precisely drill the proper size
hole at the proper angle, perpendicular the frame tube.
2. The frame manufacturer is able to properly install the Rivnuts,
tightening them to just the right torque level to avoid damaging the frame.
3. The frame manufacturer is able to install the Rivnuts prior to the
frame being painted.
4. The frame manufacturer warranties the frame, generally for life. The
end-user voids the warranty by drilling holes in the frame.*

Without a machine shop, It would be very hard for someone to drill
perfectly sized holes, perfectly straight, and compress the Rivnut to
the exact optimum tightness. In a steel frame it's not a big deal if
it's not exactly right. In an aluminum frame it's a very big deal
because the integrity of the frame will be compromised. And even if you
managed to do it properly, you've still voided your frame warranty.

Even manufacturer-installed Rivnuts occasionally cause problems. Usually
it's just the Rivnut coming loose and spinning in the hole, but
sometimes the frame ends up cracking at the site of the Rivnut.

As Jobst Brandt stated: "I don't know many riders who believe that
drilling a hole in a frame tube is a reasonable concept."
-----------------

On Saturday, July 18, 2015 at 7:29:29 PM UTC-4, sms wrote:
A MASSIVE amount of UTTER BULL**** about the hazards of installing Rivnuts when such pereceived hazards are only in his head as evidenced by tyhe hundreds if not thousands of do-it-yourself Rivnut installations done by home bicycle riders and without any frame failures.

Hey SMS, if Rivnut installations are so destructive to steel or aluminium bicycle frames please provide links to many of those frame failures where the Rivnuts were installed.

I still say Rivnut should sue you for libel!

Libel (http://dictionary.reference.com/browse/libel) 2.
anything that is defamatory or that maliciously or damagingly misrepresents..

Cheers

On 18/07/15 22:10, John B. Slocomb wrote:
On Sat, 18 Jul 2015 07:45:09 +0200, Lou Holtman
wrote:

On 2015-07-18 00:34:32 +0000, John B. Slocomb said:

On Fri, 17 Jul 2015 09:31:15 -0700, sms
wrote:

On 7/14/2015 5:06 PM, John B. Slocomb wrote:

snip

But just to be sure, are you competent to make such a statement
because you are a properly trained metal worker? You have some years
in the trade? If so could you please provide some evidence that this
is so.

You just confirmed what I said. Unless you are a properly trained metal
worker, you should not be drilling holes in your bicycle frame to put in
Rivnuts. Pretty sure most cyclists would agree with that assessment.

No, I was commenting on your ability to make an educated decision.

I think you're failing to distinguish between someone that is skilled in
metal working and a professional metal worker. I'm sure that there are
lay people out there that have a workshop at home with sufficient
equipment to be properly aligning, positioning, and drilling holes in
their frames (as long as they don't mind losing the frame's lifetime
warranty). But most cyclists don't fall into that category.

Actually I just installed some riv-nuts in an aluminum frame that I am
slowly rebuilding. The required tools were a white board marker, a
ruler, a hand drill (the sort you turn by hand) and a drill bit of
course, a nail and a rock.

Use the ruler, as a straight edge, and the marker to draw a straight
line on the frame, the ruler, as a measuring device, to mark the
distance between the holes, roughly a +- tolerance of 1/4", the nail
and rock to "center" punch the marks for drilling and the hand drill
to drill the holes.

This is rocket science and beyond the abilities of the modern
American?

I think the question is not whether you could install a rivnut, but
whether the integrity of the frame stays in tact after that. In this
regard SMS is a little paranoid.

I seriously doubt that drilling a small hole in a frame tube is going
to cause any problems, but perhaps we can have Frank do a stress
analysis on a Columbus "Airplane" Aluminum down tube. Triple butted
2.2-1.0-1.4. Tensile strength 420 mPa or ~61,000 psi. Say a 5/16"
hole.


In steel or titanium I agree. Aluminium, provided the edges of the hole
were polished. Al is notch sensitive. A burr could be the start of a
crack. CFRP is another story.

--
JS

On Saturday, July 18, 2015 at 7:29:29 PM UTC-4, sms wrote:
Yet more libelous bull****!

I gave up!

You and your libelous posts have been reported to the manufactures of Rivnuts.

I hope you hear from their lawyers!

It's one thing to mistakenly assert something but it's quite another thing to libel something, in this case Rivnuts, continually even after being told youare in error and are lying through your teeth!


Btw, I sent them your entire post with all the headers intact.

Cheers

On 7/18/2015 8:33 PM, James wrote:
On 18/07/15 22:10, John B. Slocomb wrote:

I seriously doubt that drilling a small hole in a frame tube is going
to cause any problems, but perhaps we can have Frank do a stress
analysis on a Columbus "Airplane" Aluminum down tube. Triple butted
2.2-1.0-1.4. Tensile strength 420 mPa or ~61,000 psi. Say a 5/16"
hole.


In steel or titanium I agree. Aluminium, provided the edges of the hole
were polished. Al is notch sensitive. A burr could be the start of a
crack. CFRP is another story.

One of my friends (whom I see only occasionally) is certified as an
airframe & powerplant mechanic for airplanes, although he switched
careers and became a very impressive engineer.

Anyway, I not-quite-recall him saying something about techniques used to
prevent stress concentration problems when working on aluminum airplane
skin. Perhaps peening the metal afterwards? I forget.

It's probably about time for me to pay him a visit. But in the
meantime: Anyone know about that?


--
- Frank Krygowski

On 7/18/2015 9:30 AM, jbeattie wrote:


I got a Cannondale frame replaced on a warranty even though I drilled and tapped a 3mm hole in the back of the head tube for a homemade pump peg. Considering that the frame cracked at the end of a seat stay near the dropout, I doubt my hole did much damage -- although technically, it did void the warranty. I don't think the rep noticed it.

Warranties sometimes expand or contract at the whim of the local rep.

In a conversation about automotive warranties, I was told that the
Magnuson–Moss Warranty Act prevented manufacturers from disallowing
warranty claims due to customer modifications, as long as the
modification itself didn't cause the problem in question. Isn't that true?

For an automotive example, if you put a towing hitch on a car not rated
for towing, and the door hinge breaks, they can't say "No warranty!"

And that sounds like your case.

--
- Frank Krygowski

On 7/18/2015 7:29 PM, sms wrote [regarding installing Rivnuts]:
Yeah, some people do it anyway
and nothing bad happens and they proclaim that that's "proof" that it
was a good idea, but most people have better critical thinking skills
than that.

So even in the instances where people did install Rivnuts and they
worked perfectly, your "critical thinking skills" tell you it was a bad
idea!

And despite the millions of cyclists who don't use daytime running
lights, your "critical thinking skills" tell you they're absolutely
necessary.

Despite the lack of documentation of any road riders knocked off their
bikes by running into overhead tree branches, your "critical thinking
skills" tell you we need headlights that shine upwards to protect from
these imaginary hazards.

Your "thinking" is consistent. I can't say much else for it, though.


--
- Frank Krygowski

On Sat, 18 Jul 2015 22:48:05 -0400, Frank Krygowski
wrote:

On 7/18/2015 8:33 PM, James wrote:
On 18/07/15 22:10, John B. Slocomb wrote:

I seriously doubt that drilling a small hole in a frame tube is going
to cause any problems, but perhaps we can have Frank do a stress
analysis on a Columbus "Airplane" Aluminum down tube. Triple butted
2.2-1.0-1.4. Tensile strength 420 mPa or ~61,000 psi. Say a 5/16"
hole.


In steel or titanium I agree. Aluminium, provided the edges of the hole
were polished. Al is notch sensitive. A burr could be the start of a
crack. CFRP is another story.

One of my friends (whom I see only occasionally) is certified as an
airframe & powerplant mechanic for airplanes, although he switched
careers and became a very impressive engineer.

Anyway, I not-quite-recall him saying something about techniques used to
prevent stress concentration problems when working on aluminum airplane
skin. Perhaps peening the metal afterwards? I forget.

It's probably about time for me to pay him a visit. But in the
meantime: Anyone know about that?

If you are forming an aluminum fairing, for example, and forming the
aluminum by preening it over a form or sand bag. it work hardens very
rapidly and has to be frequently annealed. The old method was to use
an oxy-acetylene torch with a rich flame and smoke the surface of the
aluminum than lean the flame down to normal and carefully heat the
aluminum until the soot just burns off. The more modern method is to
use a "magic marker" and a butane torch :-)

Of course, if one is working with any of the hardened aluminum than
you would first have to anneal the work before it was formed.
--
cheers,

John B.

On Sat, 18 Jul 2015 16:29:11 -0700, sms
wrote:

On 7/18/2015 4:33 AM, Duane wrote:

True. In my case I have 2 bikes. One is CF and won't be drilled at all.
The other is a 93 crop moly steel lugged bianchi that's too nice too be
drilled. So I have no interest either way.

Besides being a poor idea to drill either, there's no need to. You can
get a much stronger cage mount without the downsides by using one of
many accessories designed for this. You distribute the load all around
the frame tubing.

Here's a good discussion on the subject where Jobst concurs that it's a
bad idea to drill a frame for Rivnuts:
http://yarchive.net/bike/rivnuts.html. Yeah, some people do it anyway
and nothing bad happens and they proclaim that that's "proof" that it
was a good idea, but most people have better critical thinking skills
than that.

One other thing I noticed recently is that there are a lot of pretty
heavy things that use standard bottle cage mountings. You definitely
would not want to use these devices on a bicycle frame where Rivnuts
were used.

BTW, here is the section on Rivnuts from my web site on cage mounting
solutions at http://nordicgroup.us/cageboss/:

-----------------

A Word About Rivnuts

A properly installed Rivnut does not exert any stress on the inner and
outer walls of the tubing. The stress all radiates outward from the
splines of the Rivnut into the circumference of the hole.The friction
between the splines of the Rivnut and the hole keep it from rotating.

Recently, one person became very upset at my statement about Rivnuts. He
correctly points out that Rivnuts are used by many aluminum frame
manufacturers, at the factory, for bottle cage bosses. So why shouldn't
it be okay to grab an electric drill, drill some holes in a frame, and
insert some Rivnuts? The reason is because a frame manufacturer using
Rivnuts on a frame at the time it is manufactured is very different than
an end user drilling holes in their complete bicycle and trying to
properly insert Rivnuts themselves.

Here are the differences:

1. The frame manufacturer is able to precisely drill the proper size
hole at the proper angle, perpendicular the frame tube.
2. The frame manufacturer is able to properly install the Rivnuts,
tightening them to just the right torque level to avoid damaging the frame.
3. The frame manufacturer is able to install the Rivnuts prior to the
frame being painted.
4. The frame manufacturer warranties the frame, generally for life. The
end-user voids the warranty by drilling holes in the frame.*

Without a machine shop, It would be very hard for someone to drill
perfectly sized holes, perfectly straight, and compress the Rivnut to
the exact optimum tightness. In a steel frame it's not a big deal if
it's not exactly right. In an aluminum frame it's a very big deal
because the integrity of the frame will be compromised. And even if you
managed to do it properly, you've still voided your frame warranty.

Even manufacturer-installed Rivnuts occasionally cause problems. Usually
it's just the Rivnut coming loose and spinning in the hole, but
sometimes the frame ends up cracking at the site of the Rivnut.

As Jobst Brandt stated: "I don't know many riders who believe that
drilling a hole in a frame tube is a reasonable concept."
-----------------

Where ever do you get these strange ideas?

"A properly installed Rivnut does not exert any stress on the inner"

Wrong, a riv-nut both expands and shortens when it is installed this
exerts a force against the hole i.d. and also compresses the material
it is installed in between the outer riv-nut flange and the inner
protrusion where the riv-nut folds as it is compressed.

"The frame manufacturer is able to precisely drill the proper size
hole"

Firstly, the riv-nut maker determines the correct hole size and
provides this information... it is not some sort of mystery only known
to the initiated. Secondly, riv-nuts are designed to be installed in
common old "drilled" holes, not some sort of reamed to size, super
accurately sized, hole. Again, the riv-nut maker tells you this.

"The frame manufacturer is able to properly install the Rivnuts,
tightening them to just the right torque level to avoid damaging the
frame."

Again, you don't know what you are talking about. Riv-nuts are
commercially installed with an air operated "gun" that pulls the rivet
tight and is no more "precision" than driving solid rivets.

"Without a machine shop, It would be very hard for someone to drill
perfectly sized holes, perfectly straight, and compress the Rivnut to
the exact optimum tightness."

Have you even been around an aircraft manufacture or repair facility?
They spend most of their time drilling holes in aluminum and hammering
rivets in the holes.... without anything but an air drill. No machine
shop, no precision, no nothing, just a guy with a hand drill.

"In a steel frame it's not a big deal if it's not exactly right. In an
aluminum frame it's a very big deal because the integrity of the frame
will be compromised"

Again, you brilliantly illustrate your lack of knowledge.

Any time that you drill a hole in anything you "compromise the
integrity". Obviously you must, for after all where there is a hole
there is no material so that spot must be weaker. And contrary to what
you state, drilling a hole in something makes it weaker no matter what
you put in the hole. A plate with a hole in it is weaker that a plate
with no hole. And a plate with a hole in it with a rivet in the hole
is no stronger that the plate with the empty hole.

"As Jobst Brandt stated: "I don't know many riders who believe that
drilling a hole in a frame tube is a reasonable concept."

Not to disparage Brandt, but that is an extremely silly statement.

Every bicycle I see, except perhaps "fixies" have holes in the frame.
the are even drilling more holes these days to fit the shift and brake
cables inside the frame tubes.

But when I look at tube maker's catalogs I see exactly the same
dimension tube being made. In other words while the builders are now
drilling more holes the tube makers are not building new tubes that
are thicker to facilitate these extra holes.

One is forced to wonder why, if you are correct these new holy frames
don't require thicker tubes?

One is forced to the conclusion that (1) you have no knowledge of what
you are speaking, and (2) that rather than accept that you made a
mistake you are now arguing frantically in an attempt to hide the fact
that you either deliberately lied about frame holes in order to sell
some cockamamie frame clamp, or, less likely, out of sheer ignorance.
--
cheers,

John B.