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drill/tap in frames



 
 
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  #131  
Old July 17th 18, 09:10 AM posted to rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 882
Default 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.

--
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  #132  
Old July 17th 18, 09:22 AM posted to rec.bicycles.tech
Emanuel Berg[_2_]
external usenet poster
 
Posts: 882
Default 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
  #133  
Old July 17th 18, 06:11 PM posted to rec.bicycles.tech
Frank Krygowski[_2_]
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Posts: 7,031
Default 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
  #134  
Old July 17th 18, 07:40 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 882
Default 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
  #135  
Old July 17th 18, 09:38 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
external usenet poster
 
Posts: 882
Default 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
  #136  
Old Yesterday, 06:42 AM posted to rec.bicycles.tech
James[_8_]
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Posts: 5,733
Default 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.* 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
  #137  
Old Yesterday, 11:12 AM posted to rec.bicycles.tech
John B. Slocomb
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Posts: 9
Default 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.
 




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