drill/tap in frames
 

The front and rear stays, which I suppose are
welded to the frame, and painted in the same
color - these are 2 inches wide.

The bottom stay, which is a long bracket with
the form of the letter "Z", only not as
steep, has two holes, one that goes into the
BB and one that goes into the chainguard.
This is the lowest contact point of the
chainguard. This bracket is 1-1/8
inches wide.

Or perhaps "thick" or "deep" is the word.
Anyway this is how much (little) material is
required for an M5 tap to work. Because that is
what it does. This is not an exotic bike but
the standard solution which I've seen hundred
of times.

--
underground experts united
http://user.it.uu.se/~embe8573

drill/tap in frames
 

The front and rear stays, which I suppose are
welded to the frame, and painted in the same
color - these are 2 inches wide.

The bottom stay, which is a long bracket with
the form of the letter "Z", only not as
steep, has two holes, one that goes into the
BB and one that goes into the chainguard.
This is the lowest contact point of the
chainguard. This bracket is 1-1/8
inches wide.

OK, change the above into sixteenths of an inch
and it'll be correct as measured...

--
underground experts united
http://user.it.uu.se/~embe8573

drill/tap in frames
 

On Tuesday, July 17, 2018 at 4:22:48 AM UTC-4, Emanuel Berg wrote:
The front and rear stays, which I suppose are
welded to the frame, and painted in the same
color - these are 2 inches wide.

The bottom stay, which is a long bracket with
the form of the letter "Z", only not as
steep, has two holes, one that goes into the
BB and one that goes into the chainguard.
This is the lowest contact point of the
chainguard. This bracket is 1-1/8
inches wide.

OK, change the above into sixteenths of an inch
and it'll be correct as measured...

--
underground experts united
http://user.it.uu.se/~embe8573

We were discussing thread engagement. How thick are these attachment points?

Again, normal practice is to have a thread engagement in a tapped hole equal to
at least a diameter. Low stress applications can get by with less. There are
lots of small-size nuts that are thinner than that one diameter rule of thumb.

Sometimes, thin metal brackets or other items have the metal punched or
extruded to give a bit more thread engagement. Again, this is for light loads.
https://i.pinimg.com/236x/38/3d/a8/3...6deab279d9.jpg

None of this makes it a good idea to drill and tap a main frame tube, at least
not on a lightweight bike.

- Frank Krygowski

drill/tap in frames
 

Frank Krygowski wrote:

We were discussing thread engagement.
How thick are these attachment points?

Two occasions of 2/16 inches, and one 1/16 plus
change, for M5s, with no extruded part.

The load is the chainguard and chainguard
bracket stay whose weights I can report back
later tonight, God willing.

--
underground experts united
http://user.it.uu.se/~embe8573

drill/tap in frames
 

The load is the chainguard and chainguard
bracket stay whose weights I can report back
later tonight, God willing.

A typical chainguard including the bracket stay
weighs in at 160g.

--
underground experts united
http://user.it.uu.se/~embe8573

drill/tap in frames
 

On 16/07/18 01:06, Frank Krygowski wrote:
On 7/14/2018 10:20 PM, David Scheidt wrote:
AMuzi wrote:

:Some builders at the cusp of change between 'no brazed bits'
:and 'braze every possible thing' fashions (like Galmozzi)
:brazed bolts on the tube and so nuts secured the bottle
:cage. Odd looking but worked as well as anything.

I got a nasty gash from a frame like that.Â* Just picked it up, and cut
myself on the bolt.

Yet another bicycling injury!


I've had a piece of steel wire from the frayed end of a gear cable prick
my finger. Does that count? There was blood...

--
JS

drill/tap in frames
 

On Wed, 18 Jul 2018 15:42:27 +1000, James
wrote:

On 16/07/18 01:06, Frank Krygowski wrote:
On 7/14/2018 10:20 PM, David Scheidt wrote:
AMuzi wrote:

:Some builders at the cusp of change between 'no brazed bits'
:and 'braze every possible thing' fashions (like Galmozzi)
:brazed bolts on the tube and so nuts secured the bottle
:cage. Odd looking but worked as well as anything.

I got a nasty gash from a frame like that.* Just picked it up, and cut
myself on the bolt.

Yet another bicycling injury!


I've had a piece of steel wire from the frayed end of a gear cable prick
my finger. Does that count? There was blood...

O course it does. So long as you advertise it on RBT.

drill/tap in frames
 

Today I finally spent some quality time on my own bike
again, and I put on the plastic Zefal bottle cage
using cloth tape on the down tube and then two
galvanized hoose clamps. The bottle cage is designed
for screws but the result seemed solid enough.

BTW it is an interesting bike. I think it is from the
early-mid 80s. A steel frame, it has a Shimano
Positron 5 shifter, but the single chainwheel is so
big even on a flat surface, the biggest sprocket is
the only one feasible to use.

But I love it anyway thanks to the 630 wheels and
cross levers for the rim brakes.

--
underground experts exiled
http://user.it.uu.se/~embe8573

drill/tap in frames
 

On 7/25/2018 8:36 AM, Emanuel Berg wrote:
Today I finally spent some quality time on my own bike
again, and I put on the plastic Zefal bottle cage
using cloth tape on the down tube and then two
galvanized hoose clamps. The bottle cage is designed
for screws but the result seemed solid enough.

BTW it is an interesting bike. I think it is from the
early-mid 80s. A steel frame, it has a Shimano
Positron 5 shifter, but the single chainwheel is so
big even on a flat surface, the biggest sprocket is
the only one feasible to use.

But I love it anyway thanks to the 630 wheels and
cross levers for the rim brakes.


cloth tape holds moisture against the finish; poor choice of
material.

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

drill/tap in frames
 

AMuzi writes:

Today I finally spent some quality time on my own
bike again, and I put on the plastic Zefal bottle
cage using cloth tape on the down tube and then two
galvanized hoose clamps. The bottle cage is
designed for screws but the result seemed solid
enough. BTW it is an interesting bike. I think it
is from the early-mid 80s. A steel frame, it has
a Shimano Positron 5 shifter, but the single
chainwheel is so big even on a flat surface, the
biggest sprocket is the only one feasible to use.
But I love it anyway thanks to the 630 wheels and
cross levers for the rim brakes.


cloth tape holds moisture against the finish; poor
choice of material.

Against the finish?

--
underground experts exiled
http://user.it.uu.se/~embe8573