Bottle holder

On 5/23/2019 3:45 AM, John B. Slocomb wrote:

snip

But before you start telling tall tales you should realize that when
the hole is drilled it removes not only the center punch indentation
itself but considerable (in reference to the size of the center punch
dimple) material around the indentation.

It is not the issue of the punch indentation remaining, it's the issue
of using a spring-loaded punch on thin metal. But you probably wouldn't
want to do this on very thin steel either.

Bottom line is that as Jobst said, "I don't know many riders who believe
that drilling a hole in a frame tube is a reasonable concept. I assume
the rivnut was securely tightened and painted to prevent motion,
corrosion and water intrusion."

There's no reason to start drilling holes in a perfectly good frame. It
sucks that the manufacturer didn't provide the bottle cage mounts at the
time the frame was fabricated but there are many better ways of
achieving the desired result of adding a bottle holder.

On 5/23/2019 5:55 AM, AMuzi wrote:
On 5/23/2019 5:45 AM, John B. Slocomb wrote:

snip

Like door panels in cars, water always gets in. The key point of design
is to vent the piece with drainhole(s).

What percentage of frames still have drain holes in the bottom bracket?

I see all sorts of posts on mountain bike forums about drilling drain
holes in bottom brackets.

Should we all be drilling drain holes in our bottom brackets if we ride
in the rain?

On 5/23/2019 9:56 AM, sms wrote:

There is just no way that any
course in machining would not teach about how to reduce stress
concentration of holes drilled into metal. You might want to ask for a
partial refund if that school is still in existence.

SMS, will you please tell us about your personal training in machining?

I ask because you seem to have quite few odd ideas about it.

--
- Frank Krygowski

On 5/23/2019 12:53 AM, Jeff Liebermann wrote:
On Thu, 23 May 2019 10:43:29 +0700, John B. Slocomb
wrote:

I would have to say, "But Why?"

1. With a drill guide, there's no need to center punch the frame tube
or drill a pilot hole. Just clamp the jig to the tube, and drill.
2. Even with a pilot hole, keeping the drill bit from wandering is
not easy. I'm rather bad at eyeballing an electric hand drill so that
the bit is exactly perpendicular to the tube.
3. Because it's possible to do the drilling in my sleep, which is
likely to be the case.
4. With an fully assembled bicycle (or frame), an off center hole,
bad spacing between the Rivnuts, slip of the drill, or other alignment
error, and much of the bicycle might be considered scrap metal. Best
to build a proper jig and do it perfectly the first time.
5. Chances are good that one might be drilling holes in other frames
for Rivnuts. It would therefore pay to build a jig to make it easier.

After all it is only two holes about 7 cm apart. It is not, as they
say, "Rocket Science".

Not everyone has a machine shop or a machinists skills. Backyard
mechanics are not known for their precision drilling. Best to give
them a mechanical assist (i.e. a jig).

Why not just mark the spot(s) for the holes on the frame and than just
drill the holes? Even, if necessary, ding a bit of a mark on the tube
with a center punch - I say that with a certain amount of caution, as
I don't mean Whap It!, just a tiny little dimple, just enough to get
the drill started. Then drill a pilot hole with, maybe a 1/16" drill,
to make sure that the full size drill doesn't wander off the mark.
Than just drill it.

Sounds good, which brings me back to the previous problem. How is one
going to rigidly clamp the frame to be able to drill the holes?
However, that's now where the aforementioned procedure is going to
screw up. What will happen is that both the center punch mark and
pilot hole will probably be perfectly placed. What will fail is that
the actual Rivnut hole drill will wander sideways if the drill is not
perfectly perpendicular to the tubing. The drill needs some kind of
clamping jig to keep it perpendicular. If it can't be done on a drill
press or mill, then clamping a v-block and drill guide to the tube is
a good substitute.

You don't even have to be terribly accurate as all the bottle cages
I've seen have at least one of the mounting holes elongated to fit
even if the mounting holes in the frame aren't perfectly spaced.

Remind me not to let you work on any of my bicycles.

I think that, like many things, it's a question of benefits vs.
detriments. A person with an average mechanic's skill who is going to
Rivnut one water bottle cage - or even one per year - probably needn't
bother buying such a jig.

A person who routinely builds frames, or modifies them for customers,
will probably recoup the cost of the jig in time savings after just a
few frames.

And the jig might be appropriate for the kind of person who thinks
drilling two holes requires a fully equipped machine shop. It's a
"safety inflation" way to do a simple job even safer!

IOW, it's a nice "safety" addition to one's collection: bike helmet,
day-glo vest, super-bright high-beam daytime running light headlight,
nautical strobe beacon taillight, horizontal flippy flag, electric horn,
etc. etc. etc.


--
- Frank Krygowski

On 5/22/2019 11:56 PM, sms wrote:

Good idea to use this kind of tool to keep the bit straight and to
prevent it from wandering, since you probably don't want to use a center
punch on an aluminum frame.

Why on earth would you not want to use a center punch before drilling an
aluminum frame?

(What was your machine shop training??)

Also to achieve proper spacing.

What do you suppose the tolerance is on that hole-to-hole spacing? Do
you really think it's measured in thousandths of an inch?


--
- Frank Krygowski

On 5/23/2019 1:16 AM, Jeff Liebermann wrote:
On Tue, 21 May 2019 21:21:12 -0400, Joy Beeson
wrote:

I'm puzzled by the comment that one could cut oneself on the metal
strap. I've been scratched by various bike parts, but the hose clamps
have never even thought about it.

That would be me. What I did was cut off the loose end of the metal
strap flush with the hole clamp body. The down tube paint was
protected by a strip of hard rubber. Over a few months, the clamp and
rubber strip decided to move. So I tightened the screw on the clamp,
which then exposed the end of the metal strap from the clamp body. I
had previously rounded the sharp corners, but did not deburr the cut
end. The result was a rather messy, but fortunately not very deep,
slice in my leg when I performed an unscheduled and graceless
dismount. I cut the metal strap shorter to avoid a repeat
performance, but did nothing with the exposed hex screw head, which
produced a minor gouge in the same place on my leg about a year later.

Sorry to jump context, but both of those boo-boos would have been
registered in the Portland study of bike commuters, Hoffman et. al.,
"Bicycle Commuter Injury Prevention," Journal of Trauma, V. 69 No. 5

They took great pains to record _every_ injury, no matter how tiny, and
used the results to say we need bike lanes everywhere.

IOW: Scratched by your hose clamp? Oh, if only there were a bike lane!!!

Back to the topic: I'm a big fan of deburring sharp edges. It takes only
a few seconds with a fine grinding wheel or a hand file.


--
- Frank Krygowski

On 5/23/2019 9:25 AM, sms wrote:
On 5/23/2019 5:55 AM, AMuzi wrote:
On 5/23/2019 5:45 AM, John B. Slocomb wrote:

snip

Like door panels in cars, water always gets in. The key
point of design is to vent the piece with drainhole(s).

What percentage of frames still have drain holes in the
bottom bracket?

I see all sorts of posts on mountain bike forums about
drilling drain holes in bottom brackets.

Should we all be drilling drain holes in our bottom brackets
if we ride in the rain?

Rain? Condensation from outdoors to room temperature and
back is enough. Drainholes would have avoided these:
http://www.yellowjersey.org/coln14b.jpg

If only the holes were drilled to actually vent instead of
being small and blocked by the headset cups. I take a lot of
frames apart and internal rust of any significance is rare,
almost always in unvented frames.

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

On 23/05/2019 8:49 a.m., AMuzi wrote:
On 5/22/2019 10:56 PM, sms wrote:
On 5/22/2019 7:59 PM, Jeff Liebermann wrote:

snip

Ok, I yield.* A V-block won't work on a finished bicycle
frame.* I
tend to think in terms of what can be done on a drill
press or milling
machine.* As you might suspect, I've never used Rivnuts on
an a frame.
Water Bottle Mount Drill Jig
https://www.steintool.com/portfolio-items/water-bottle-mount-drill-jig/



snip

Good idea to use this kind of tool to keep the bit straight
and to prevent it from wandering, since you probably don't
want to use a center punch on an aluminum frame. Also to
achieve proper spacing. You could use this on a finished
frame with a right-angle drill.

One person wrote: "I found that a standard power drill was
difficult to align on the cylindrical steel tube; the bit
tended to drift around the tube. Even after I created a
small pilot hole for each boss, the bigger drill bit shifted
to the side a little. In the end, once the cage was bolted
in place, I realized that one of the bosses was misaligned
along its cylindrical axis. Fortunately, it wasn’t off by
much, but it tweaked the alignment ever so slightly and
caused the cage to twist."

Of course if you do go the Rivnut route you also want to
ensure that you seal everything so moisture can't get in
since you won't be painting the frame afterward.

"don't want to use a center punch on an aluminum frame."
Why ever not?

"drill bit shifted to the side a little."
With a centerpunch dimple and a drill sharpened to be symmetric they
don't walk.




Much simpler to just make sure the bike has a couple of water bottle
mounts when you buy it...

On Thursday, May 23, 2019 at 10:18:56 AM UTC-4, sms wrote:
On 5/23/2019 3:45 AM, John B. Slocomb wrote:

snip

But before you start telling tall tales you should realize that when
the hole is drilled it removes not only the center punch indentation
itself but considerable (in reference to the size of the center punch
dimple) material around the indentation.

It is not the issue of the punch indentation remaining, it's the issue
of using a spring-loaded punch on thin metal. But you probably wouldn't
want to do this on very thin steel either.

Bottom line is that as Jobst said, "I don't know many riders who believe
that drilling a hole in a frame tube is a reasonable concept. I assume
the rivnut was securely tightened and painted to prevent motion,
corrosion and water intrusion."

There's no reason to start drilling holes in a perfectly good frame. It
sucks that the manufacturer didn't provide the bottle cage mounts at the
time the frame was fabricated but there are many better ways of
achieving the desired result of adding a bottle holder.

BULL****! Rivnuts are one of the simplest most elegant ways of adding mounts for bottle cages there is. Once installed a Rivnut looks just like a factory installation or even a brazed on bottle fitting. I can only assume from your posts that you do NOT know how to drill a simple hole in a bicycle tube nor do you know how easy it is to install a Rivnut in a hole in a bicycle tube.

Cheers

On Thu, 23 May 2019 07:49:10 -0500, AMuzi wrote:

On 5/22/2019 10:56 PM, sms wrote:
On 5/22/2019 7:59 PM, Jeff Liebermann wrote:

snip

Ok, I yield. A V-block won't work on a finished bicycle
frame. I
tend to think in terms of what can be done on a drill
press or milling
machine. As you might suspect, I've never used Rivnuts on
an a frame.
Water Bottle Mount Drill Jig
https://www.steintool.com/portfolio-items/water-bottle-mount-drill-jig/


snip

Good idea to use this kind of tool to keep the bit straight
and to prevent it from wandering, since you probably don't
want to use a center punch on an aluminum frame. Also to
achieve proper spacing. You could use this on a finished
frame with a right-angle drill.

One person wrote: "I found that a standard power drill was
difficult to align on the cylindrical steel tube; the bit
tended to drift around the tube. Even after I created a
small pilot hole for each boss, the bigger drill bit shifted
to the side a little. In the end, once the cage was bolted
in place, I realized that one of the bosses was misaligned
along its cylindrical axis. Fortunately, it wasn’t off by
much, but it tweaked the alignment ever so slightly and
caused the cage to twist."

Of course if you do go the Rivnut route you also want to
ensure that you seal everything so moisture can't get in
since you won't be painting the frame afterward.

"don't want to use a center punch on an aluminum frame."
Why ever not?

"drill bit shifted to the side a little."
With a centerpunch dimple and a drill sharpened to be
symmetric they don't walk.

Ah but... it sounds as though your shop can sharpen a drill bit, but
from what I read here it is a very difficult task that only certain
shops can accomplish :-)

Perhaps the subject got an advert? We can sharpen a drill bit!
--

Cheers,

John B.