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drill/tap in frames



 
 
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  #51  
Old July 11th 18, 07:42 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 1,035
Default drill/tap in frames

Joy Beeson wrote:

I put it there with cable ties ("wires") but
there was an annoying sound while riding
the bike.


You need a hose clamp. Wrap the tube with
handlebar tape to protect the paint. Also,
clamp on tape has a much higher co-efficient
of friction than clamp on hard surface.

I attached two bottle cages this way late in
the twentieth century, and haven't thought
about them since.


Good idea, I'll try that next. The hose clamp
is an underrated commodity when it comes
to bikes.

--
underground experts united
http://user.it.uu.se/~embe8573
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  #52  
Old July 11th 18, 07:48 PM posted to rec.bicycles.tech
AMuzi
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Posts: 9,769
Default drill/tap in frames

On 7/11/2018 11:42 AM, Jeff Liebermann wrote:
On Tue, 10 Jul 2018 20:41:08 -0700, John B. Slocomb
wrote:

On Sat, 07 Jul 2018 12:33:38 -0700, Jeff Liebermann
wrote:

On Sat, 7 Jul 2018 11:06:52 -0400, Frank Krygowski
wrote:

This group has debated Rivnuts extensively. One poster claims nobody
should install a Rivnut unless he has access to a complete machine shop.
Others with more experience have said that the installation is easy for
anyone with normal mechanical skills.

That would be SMS (Steven Scharf) on one of his web pages:
http://nordicgroup.us/cageboss/

Since I've made a mess with all the available technologies, Rivnuts
(steel and aluminum), brazing (steel), TIG (aluminum), and epoxy glue
(plastic boss on aluminum), I'll remain neutral on the matter.

Hint: Use steel Rivnuts on steel frames, aluminum Rivnuts on aluminum
frame, and plastic straps or clamps on CF (carbon fiber).


One can only suppose that those "dumb asses: that manufacture rivnuts
deliberately make their product in a number of materials :-)


I'm not sure about the deliberate part, but yes, one can buy them in
steel or aluminum. I couldn't find any plastic or carbon fiber
rivnuts.

And, it might be added that not knowing what you are doing is not
limited to bicycle maintenence :-)


True. If those expounding on bicycle technology by various electronic
means really knew what they were doing, they would be riding instead
of pounding on the keyboard. If you really want to know how things
work, find someone that is actually doing the work and interrogate
them for the information you need and don't bother reading books,
manufacturers literature, magazines, forums, and newsgroups. The only
downside is that those who really know, tend to be inarticulate and
have difficulties explaining complex concepts, like which way to
tighten a right handed bolt. However, persistence, intimidation, and
perhaps bribery will eventually produce the required answer from a
real expert.

As I mentioned, I have successfully trashed most everything I've tried
to do with Rivnuts on bicycles, and therefore have no opinion on the
matter. However, it might be interesting to try a simple test. I
could probably finance the test by taking bets on the outcome.

Take two identical lengths of steel bicycle tubing. Install a Rivnut
in only one tube at midpoint. Clamp one end in a pipe vise. Pull on
the other end with a Come-Along perpendicular to the tubing. Measure
the force with a load cell. Draw a graph to show when the tubing went
plastic and eventually buckled. Compare results between the tubing
with and without the Rivnut. That should settle the debate whether
Rivnuts are detrimental to frame and stay strength.


I think the question isn't so much 'has the tube's ultimate
strength been diminished?' but rather 'is it yet strong
enough for expected application?'.

In theory and in absolute yes the tube is less strong. In
practice, from Santana ExoGrid tandems to Bianchi thinwall
tempered aluminum models, to their carbon bikes, rivnuts are
not a failure point.

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


  #53  
Old July 11th 18, 09:50 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 6,335
Default drill/tap in frames

On 7/11/2018 2:42 PM, Emanuel Berg wrote:
Joy Beeson wrote:

I put it there with cable ties ("wires") but
there was an annoying sound while riding
the bike.


You need a hose clamp. Wrap the tube with
handlebar tape to protect the paint. Also,
clamp on tape has a much higher co-efficient
of friction than clamp on hard surface.

I attached two bottle cages this way late in
the twentieth century, and haven't thought
about them since.


Good idea, I'll try that next. The hose clamp
is an underrated commodity when it comes
to bikes.


Not by Joerg! ;-)


--
- Frank Krygowski
  #54  
Old July 11th 18, 09:58 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 6,335
Default drill/tap in frames

On 7/11/2018 2:38 AM, Emanuel Berg wrote:
Frank Krygowski wrote:

There also seems to be a horizontal welded
tab protruding from the seat tube above the
chainring. (Or underneath the chainring in
the photo of the inverted bike.) That may be
a mounting point for the top surface of
the chainguard.

The chainguard also seems to have a bracket
that would connect the chainguard's bottom to
the underside of the bottom bracket area of
the frame. Perhaps that's the spot he wants
to drill and tap?


The chainguard typically has a three stays.

One down below, to the bottom bracket. There is
a threaded hole both ways, i.e.
two such occurrences.

One stay front. There is usually two threaded
holes on the stay/chainguard interface.
But here there is more variation as sometimes
it is a bent bracket screwed into the frame,
also threaded with no nut. But sometimes the
bracket appears to be an extention of the
frame, I suppose it is welded as it is
a steel frame.

Then there is a stay at the back. This is
sometimes a likewise extention of the frame as
above (with a single threaded hole) but
sometimes it is a loose part, a bracket bent
around the seat stay tube, much like the
component that connects the rear hub brake arm
to the chain stay. If this is the case, there
is no threading to it, save for the bolt that
has a nut on the other side.

Actually this is not what I had in mind for
drilling and tapping, that was a bottle cage on
the down/diagonal tube. I put it there with
cable ties ("wires") but there was an annoying
sound while riding the bike.


So your real objective is to fasten a bottle cage to the down tube? Then
you should definitely not just drill and tap the frame tube itself. A
Rivnut can work. So can various clamp arrangements - yes, including
screw-type hose clamps.

The chainguard
stay example I brought up to contradict the
claim that it cannot be done because of too
thin tube walls. The stays are not very thin,
and besides they are screwed into the frame, so
there are possibly two, at least one example
how a small width would suffice. I write
"possibly" because it was brought up possibly
the tubes are butted. I doubt that because
these bikes are commuter bikes, solid, but not
optimized. But I suppose anything is possible.


The normal rule of thumb - i.e. threaded portion at least equal to the
diameter, and preferably 1.5 times diameter - is sometimes successfully
violated. It depends on the magnitude and direction of the loads, as
well as the consequences of failure. But I wouldn't try tapping the down
tube of a bike.


--
- Frank Krygowski
  #55  
Old July 11th 18, 10:24 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 6,335
Default drill/tap in frames

On 7/11/2018 2:48 PM, AMuzi wrote:
On 7/11/2018 11:42 AM, Jeff Liebermann wrote:
On Tue, 10 Jul 2018 20:41:08 -0700, John B. Slocomb
wrote:

On Sat, 07 Jul 2018 12:33:38 -0700, Jeff Liebermann
wrote:

On Sat, 7 Jul 2018 11:06:52 -0400, Frank Krygowski
wrote:

This group has debated Rivnuts extensively. One poster claims nobody
should install a Rivnut unless he has access to a complete machine
shop.
Others with more experience have said that the installation is easy
for
anyone with normal mechanical skills.

That would be SMS (Steven Scharf) on one of his web pages:
http://nordicgroup.us/cageboss/

Since I've made a mess with all the available technologies, Rivnuts
(steel and aluminum), brazing (steel), TIG (aluminum), and epoxy glue
(plastic boss on aluminum), I'll remain neutral on the matter.

Hint:¬* Use steel Rivnuts on steel frames, aluminum Rivnuts on aluminum
frame, and plastic straps or clamps on CF (carbon fiber).


One can only suppose that those "dumb asses: that manufacture rivnuts
deliberately make their product in a number of materials :-)


I'm not sure about the deliberate part, but yes, one can buy them in
steel or aluminum.¬* I couldn't find any plastic or carbon fiber
rivnuts.

And, it might be added that not knowing what you are doing is not
limited to bicycle maintenence :-)


True.¬* If those expounding on bicycle technology by various electronic
means really knew what they were doing, they would be riding instead
of pounding on the keyboard.¬* If you really want to know how things
work, find someone that is actually doing the work and interrogate
them for the information you need and don't bother reading books,
manufacturers literature, magazines, forums, and newsgroups.¬* The only
downside is that those who really know, tend to be inarticulate and
have difficulties explaining complex concepts, like which way to
tighten a right handed bolt.¬* However, persistence, intimidation, and
perhaps bribery will eventually produce the required answer from a
real expert.

As I mentioned, I have successfully trashed most everything I've tried
to do with Rivnuts on bicycles, and therefore have no opinion on the
matter.¬* However, it might be interesting to try a simple test.¬* I
could probably finance the test by taking bets on the outcome.

Take two identical lengths of steel bicycle tubing.¬* Install a Rivnut
in only one tube at midpoint.¬* Clamp one end in a pipe vise.¬* Pull on
the other end with a Come-Along perpendicular to the tubing.¬* Measure
the force with a load cell.¬* Draw a graph to show when the tubing went
plastic and eventually buckled.¬* Compare results between the tubing
with and without the Rivnut.¬* That should settle the debate whether
Rivnuts are detrimental to frame and stay strength.


I think the question isn't so much 'has the tube's ultimate strength
been diminished?' but rather 'is it yet strong enough for expected
application?'.


Exactly. Strong enough is strong enough.

And BTW, the test you're describing would be much, much easier to do in
a proper tensile testing machine. Find an engineering student, get him
interested, have him get permission to do it as a class project, and
your data would be much better.

But on the other hand, tensile strength of the tube isn't really the
concern. The concern would be fatigue strength, and if we're talking
about the down tube, it would be under repeated, reversing torsional
stresses.

I strongly suspect that you'd find no significant difference. One
feature of the Rivnut is that its clamping action on the parent metal
applies compressive stress. Fatigue cracks start in regions of tensile
stress. The Rivnut may even make the object stronger.

In theory and in absolute yes the tube is less strong. In practice, from
Santana ExoGrid tandems to Bianchi thinwall tempered aluminum models, to
their carbon bikes, rivnuts are not a failure point.


And that's really all you need to know, apart from how to properly
install them. (No, it doesn't require a machine shop.)

--
- Frank Krygowski
  #56  
Old July 11th 18, 10:29 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 6,335
Default drill/tap in frames

On 7/11/2018 1:18 PM, Jeff Liebermann wrote:
On Tue, 10 Jul 2018 21:25:06 -0700, John B. Slocomb
wrote:

One might comment that a fairly large number of bridges, that
subsequently fell down, were designed by the engineers of the times
:-)


Therefore, anything designed by an engineer will eventually fall
apart. I like the logic.

The problem with mechanical engineering is that problems, such as
falling bridges, are easily visible. Even Joe Sixpack can recognize a
mechanical failure. The fault is always with the architect or
designer, and never with cost cutting contractor, sloppy construction
company, defective imported components, blind inspectors, bribed
officials, or the demands of the aesthetics committees. It's for this
reason that I chose to go into electronics. Few can recognize an
electronic problem or find someone on the design staff to blame. It's
safety through obscurity.


More on that theme: http://dilbert.com/strip/1994-06-10

I was once assigned the task of rationalizing countless pages of
spaghetti code that was controlling various robotic workcells. The
original author was probably ****ed that I succeeded.


--
- Frank Krygowski
  #57  
Old July 11th 18, 10:44 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 6,335
Default drill/tap in frames

On 7/11/2018 12:25 AM, John B. Slocomb wrote:

One might comment that a fairly large number of bridges, that
subsequently fell down, were designed by the engineers of the times


Locally, the current hot problem is a historic and well-loved pedestrian
suspension bridge in a park.

One know-it-all claims he talked to one engineer who said "It's reached
the end of its useful life" and offered to design a replacement for
several thousand dollars, which would require many tens of thousands of
dollars to build. Know-it-all wanted the village to hire the guy on the
spot.

When there was skepticism, the know-it-all (a marketing guy, BTW)
brought in another engineer. Know-it-all claims this engineer said "I'd
close it immediately for safety reasons." No details from either of
those engineers on what might possibly fail. In fact, no direct
communication from them at all. All we have is know-it-all's version of
their views.

Meanwhile another registered Professional Engineer examined it and
reported in detail, saying that there is no danger at all, that safety
factors are in the hundreds, that only minor repairs are needed, and
that those can be done by volunteers.

I'm a retired PE, and I agree with that guy. But we'll see which way the
politics go.

--
- Frank Krygowski
  #58  
Old July 11th 18, 11:29 PM posted to rec.bicycles.tech
John B. Slocomb
external usenet poster
 
Posts: 88
Default drill/tap in frames

On Wed, 11 Jul 2018 07:42:26 -0700, sms
wrote:

On 7/9/2018 11:16 AM, David Scheidt wrote:

he was also wrong about many things. Every bike I've ever had has had
holes drilled in it. Clearly, there is a range of holes that do not
cause failure, and some that do. The question is where does a rivnut
fall? I wouldn't drill a 5 mm hole a on 26mm diameter tube, but they
work fine on large diamter ones.


Did you drill those holes and install the Rivnuts or did they come from
the factory that way. Were these steel or aluminum tubes?

Rivnuts in very thin tubing need to be installed very carefully. Drill
them with the wrong drill and you'll crack the tubing. Install them too
loose and they'll spin. Install them too tight and they cause cracking.

You can get away with doing this but it doesn't mean that it's a good
idea. There's a reason why all the experts advise against doing this,
and why it voids the frame warranty (if you're the original owner with a
lifetime warranty, you might worry about this).


Err.... Crack the tubing? How so? Is there some sort of magic here?
Drill a hole a tiny bit larger then optimum and CRACK! The tube
cracks?

You just seem to delight in telling us just how little you know about
what you are talking about.

As you also obviously know little about rivnuts you might be
interested in knowing that the Rivnut people are very explicit in
specifying dimensions and even how tight to compress them when
installing them. See:
https://www.google.com/search?tbm=is...i h=660&dpr=1
for some examples.

Searching for "rivnut+specification" will return some 65,000 hits
specifying all kinds of information useful to the embryo rivnut
installer. And even to the experienced.

Given that the rivnut company has published their installation data
for you to read. Read it. You don't have to be a dumb ass.


For those determined to do this, look into the Plusnut (made by Rivnut)
which is more suitable for end-user applications.


Why do you say that? After all Rivnut advocates their Plusnuts as
"Ideal for plastics and thin sheet metal applications where ultimate
pull-out strength is required." Have you seen a lot of rivnuts ripped
out of the frame tubes by sheer force?

For the OP, is the chainstay even a large enough diameter for a Rivnut?

What might work is using M3 x 0.25 screws. You'd have enough threads for
a 1 mm thick tube. Both the screws and the taps are not cheap as these
are used on high-precision machinery. Tthey also have M6 x 0.25, but I
did not see any M5.


--

Cheers,

John B.
  #59  
Old July 11th 18, 11:37 PM posted to rec.bicycles.tech
John B. Slocomb
external usenet poster
 
Posts: 88
Default drill/tap in frames

On Wed, 11 Jul 2018 07:45:09 -0700, sms
wrote:

On 7/10/2018 6:02 PM, jbeattie wrote:

snip

it was a schizophrenic time, unlike today when we have it all together, and the technology is perfect.


I tell my kids, ďback in my day, people didnít think it was a good idea
to grab an electric drill and drill holes in you bicycle frame, now we
know better.Ē


Strange isn't it? After all the normal road bike frame has holes in
it. Usually, as a minimum, 4 for bottle cages, one for seat tube clamp
and another one or two for the derailers , quite frequently 6 to 8
more for the fenders (Oh, I forgot, "it never rains in southern
California") and a couple for racks. I've even got a couple of frames
with holes drilled for the shifters.

Some of these frames are 25 or more years old and haven't cracked
yet.... how long do I have to wait?
--

Cheers,

John B.
  #60  
Old July 11th 18, 11:39 PM posted to rec.bicycles.tech
SMS
external usenet poster
 
Posts: 8,334
Default drill/tap in frames

On 7/11/2018 11:42 AM, Emanuel Berg wrote:
Joy Beeson wrote:

I put it there with cable ties ("wires") but
there was an annoying sound while riding
the bike.


You need a hose clamp. Wrap the tube with
handlebar tape to protect the paint. Also,
clamp on tape has a much higher co-efficient
of friction than clamp on hard surface.

I attached two bottle cages this way late in
the twentieth century, and haven't thought
about them since.


Good idea, I'll try that next. The hose clamp
is an underrated commodity when it comes
to bikes.


No it's not. It's an over-rated kludge.

 




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