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Curiosity Killed the Cat



 
 
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  #11  
Old January 13th 17, 01:26 AM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Posts: 10,538
Default Curiosity Killed the Cat

On 1/12/2017 5:00 PM, AMuzi wrote:
On 1/12/2017 3:31 PM, Doug Landau wrote:
On Thursday, January 12, 2017 at 1:22:14 PM UTC-8,
wrote:
Frank,

With all of this talk about heating the bottom bracket to get it
apart why didn't you explain and show the calculation that
demonstrated that the steel cup and the aluminum bottom bracket tube
hung on an aluminum frame would have a difference in expansion of a
couple of thousandths of an inch max even if you COULD get the
aluminum to heat faster than the steel cup?

After all, if you blow hot air down there the steel cup with a much
lower conduction rate would be getting warmer than the frame with
aluminum having between four and six times the heat conduction of
hardened steel and there only being a 44% difference in expansion
rates to begin with.

This is something that's right up your alley while we had all these
things from using a hair dryer to a welding torch trying to light the
frame on fire.

Since an 80 C warming difference in expansion would only be a couple
mils and what normally jams these cups in is rust expansion from
water leaking down the seat tube and onto the threads that are
slightly in the open part of the seat tube and bottom bracket
interface, this expansion can easily be twice or more what the
expansion could ever achieve even if you could get the bottom bracket
significantly warmer than the cup.

Or where you sitting back and enjoying the show? This assault on poor
Ted with everything from lighting his frame on fire to pounding it
into flakes with a hammer was pretty entertaining as long as you
weren't Ted unaware that most of the help here isn't since the exit
of Jobst and Sheldon.


How does the title of this thread relate to the subject?


Long leadup to:

Mrs Schrodinger asked, "What have you done to the cat? She looks
half-dead."


:-)


--
- Frank Krygowski
Ads
  #12  
Old January 13th 17, 01:32 AM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Posts: 10,538
Default Curiosity Killed the Cat

On 1/12/2017 4:22 PM, wrote:
Frank,

With all of this talk about heating the bottom bracket to get it apart why didn't you explain and show the calculation that demonstrated that the steel cup and the aluminum bottom bracket tube hung on an aluminum frame would have a difference in expansion of a couple of thousandths of an inch max even if you COULD get the aluminum to heat faster than the steel cup?

After all, if you blow hot air down there the steel cup with a much lower conduction rate would be getting warmer than the frame with aluminum having between four and six times the heat conduction of hardened steel and there only being a 44% difference in expansion rates to begin with.

This is something that's right up your alley while we had all these things from using a hair dryer to a welding torch trying to light the frame on fire.

Since an 80 C warming difference in expansion would only be a couple mils and what normally jams these cups in is rust expansion from water leaking down the seat tube and onto the threads that are slightly in the open part of the seat tube and bottom bracket interface, this expansion can easily be twice or more what the expansion could ever achieve even if you could get the bottom bracket significantly warmer than the cup.

Or where you sitting back and enjoying the show? This assault on poor Ted with everything from lighting his frame on fire to pounding it into flakes with a hammer was pretty entertaining as long as you weren't Ted unaware that most of the help here isn't since the exit of Jobst and Sheldon.


Sorry, I didn't (and don't) find it all that interesting.

Anyway, if I were to try heating for the differential expansion, I
wouldn't do it the way you describe. And I wouldn't do it until trying
quite a few other techniques.

FWIW, I liked the Sheldon tool that Sir pointed out. And Blaster. With
a bench vise. But YMMV.

--
- Frank Krygowski
  #13  
Old January 13th 17, 06:09 AM posted to rec.bicycles.tech
Tosspot[_3_]
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Posts: 1,563
Default Curiosity Killed the Cat

On 12/01/17 23:00, AMuzi wrote:
On 1/12/2017 3:31 PM, Doug Landau wrote:


snip

How does the title of this thread relate to the subject?


Long leadup to:

Mrs Schrodinger asked, "What have you done to the cat? She looks
half-dead."


Door! ----
  #14  
Old January 13th 17, 07:33 PM posted to rec.bicycles.tech
Benderthe.evilrobot
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Posts: 128
Default Curiosity Killed the Cat


"Frank Krygowski" wrote in message
news
On 1/12/2017 4:22 PM, wrote:
Frank,

With all of this talk about heating the bottom bracket to get it apart
why didn't you explain and show the calculation that demonstrated that
the steel cup and the aluminum bottom bracket tube hung on an aluminum
frame would have a difference in expansion of a couple of thousandths of
an inch max even if you COULD get the aluminum to heat faster than the
steel cup?

After all, if you blow hot air down there the steel cup with a much lower
conduction rate would be getting warmer than the frame with aluminum
having between four and six times the heat conduction of hardened steel
and there only being a 44% difference in expansion rates to begin with.

This is something that's right up your alley while we had all these
things from using a hair dryer to a welding torch trying to light the
frame on fire.

Since an 80 C warming difference in expansion would only be a couple mils
and what normally jams these cups in is rust expansion from water leaking
down the seat tube and onto the threads that are slightly in the open
part of the seat tube and bottom bracket interface, this expansion can
easily be twice or more what the expansion could ever achieve even if you
could get the bottom bracket significantly warmer than the cup.

Or where you sitting back and enjoying the show? This assault on poor Ted
with everything from lighting his frame on fire to pounding it into
flakes with a hammer was pretty entertaining as long as you weren't Ted
unaware that most of the help here isn't since the exit of Jobst and
Sheldon.


Sorry, I didn't (and don't) find it all that interesting.

Anyway, if I were to try heating for the differential expansion, I
wouldn't do it the way you describe. And I wouldn't do it until trying
quite a few other techniques.


Agreed - for me; heating it is pretty much a last resort.

Unlike Tom - I learn from my mistakes.

  #15  
Old January 13th 17, 11:41 PM posted to rec.bicycles.tech
Phil Lee
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Posts: 248
Default Curiosity Killed the Cat

AMuzi considered Thu, 12 Jan 2017 16:00:13 -0600
the perfect time to write:

On 1/12/2017 3:31 PM, Doug Landau wrote:
On Thursday, January 12, 2017 at 1:22:14 PM UTC-8, wrote:
Frank,

With all of this talk about heating the bottom bracket to get it apart why didn't you explain and show the calculation that demonstrated that the steel cup and the aluminum bottom bracket tube hung on an aluminum frame would have a difference in expansion of a couple of thousandths of an inch max even if you COULD get the aluminum to heat faster than the steel cup?

After all, if you blow hot air down there the steel cup with a much lower conduction rate would be getting warmer than the frame with aluminum having between four and six times the heat conduction of hardened steel and there only being a 44% difference in expansion rates to begin with.

This is something that's right up your alley while we had all these things from using a hair dryer to a welding torch trying to light the frame on fire.

Since an 80 C warming difference in expansion would only be a couple mils and what normally jams these cups in is rust expansion from water leaking down the seat tube and onto the threads that are slightly in the open part of the seat tube and bottom bracket interface, this expansion can easily be twice or more what the expansion could ever achieve even if you could get the bottom bracket significantly warmer than the cup.

Or where you sitting back and enjoying the show? This assault on poor Ted with everything from lighting his frame on fire to pounding it into flakes with a hammer was pretty entertaining as long as you weren't Ted unaware that most of the help here isn't since the exit of Jobst and Sheldon.


How does the title of this thread relate to the subject?


Long leadup to:

Mrs Schrodinger asked, "What have you done to the cat? She
looks half-dead."


Well, there's some good news, and some bad news.
  #16  
Old January 14th 17, 05:01 PM posted to rec.bicycles.tech
Tim McNamara
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Posts: 6,945
Default Curiosity Killed the Cat

On Fri, 13 Jan 2017 11:25:58 +1100, James wrote:
On 13/01/17 09:00, AMuzi wrote:


Long leadup to:

Mrs Schrodinger asked, "What have you done to the cat? She looks
half-dead."


Which half?


I am not certain of that.
  #17  
Old January 14th 17, 08:34 PM posted to rec.bicycles.tech
AMuzi
external usenet poster
 
Posts: 13,447
Default Curiosity Killed the Cat

On 1/14/2017 11:01 AM, Tim McNamara wrote:
On Fri, 13 Jan 2017 11:25:58 +1100, James wrote:
On 13/01/17 09:00, AMuzi wrote:


Long leadup to:

Mrs Schrodinger asked, "What have you done to the cat? She looks
half-dead."


Which half?


I am not certain of that.


But we know the velocity.

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


  #18  
Old January 14th 17, 09:16 PM posted to rec.bicycles.tech
Andrew Chaplin
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Posts: 206
Default Curiosity Killed the Cat

AMuzi wrote in news
On 1/14/2017 11:01 AM, Tim McNamara wrote:
On Fri, 13 Jan 2017 11:25:58 +1100, James
wrote:
On 13/01/17 09:00, AMuzi wrote:


Long leadup to:

Mrs Schrodinger asked, "What have you done to the cat? She looks
half-dead."


Which half?


I am not certain of that.


But we know the velocity.


Is it African or European?
--
Andrew Chaplin
SIT MIHI GLADIUS SICUT SANCTO MARTINO
(If you're going to e-mail me, you'll have to get "yourfinger." out.)
  #19  
Old January 14th 17, 09:53 PM posted to rec.bicycles.tech
Duane[_4_]
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Posts: 1,546
Default Curiosity Killed the Cat

Andrew Chaplin wrote:
AMuzi wrote in news
On 1/14/2017 11:01 AM, Tim McNamara wrote:
On Fri, 13 Jan 2017 11:25:58 +1100, James
wrote:
On 13/01/17 09:00, AMuzi wrote:

Long leadup to:

Mrs Schrodinger asked, "What have you done to the cat? She looks
half-dead."


Which half?

I am not certain of that.


But we know the velocity.


Is it African or European?


Laden or unladen?

--
duane
  #20  
Old January 15th 17, 02:24 AM posted to rec.bicycles.tech
Tim McNamara
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Posts: 6,945
Default Curiosity Killed the Cat

On Sat, 14 Jan 2017 14:34:30 -0600, AMuzi wrote:
On 1/14/2017 11:01 AM, Tim McNamara wrote:
On Fri, 13 Jan 2017 11:25:58 +1100, James
wrote:
On 13/01/17 09:00, AMuzi wrote:


Long leadup to:

Mrs Schrodinger asked, "What have you done to the cat? She looks
half-dead."


Which half?


I am not certain of that.


But we know the velocity.


Good, but for some reason I can't locate the cat.
 




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