U
Umterp
Guest
Anyone have any experience with this type of fork? I'm thinking of buying one, but then someone told
me they break easily.
Any feedback appreciated.
Thanks,
Dave
me they break easily.
Any feedback appreciated.
Thanks,
Dave
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R
Rik O'Shea
Guest
[email protected] (UMTERP) wrote in message news:<[email protected]>...
> Anyone have any experience with this type of fork? I'm thinking of buying one, but then someone
> told me they break easily.
>
> Any feedback appreciated.
>
> Thanks,
>
> Dave
The consensus seems to be that carbon forks will last a lifetime (even longer than steel) if they
are not crashed.
From Columbus: Carbon forks can be long lasting but one has to take care of other aspects than
metal ones.
A fiber composite material has higher mechanical characteristics than metals (higher tensile
strength, higher fatigue life, higher stiffness) but it has even different behavior due to its "non-
homogeneous nature". This means that the fork project is really a "critical point" for life span,
moreover the final user has to check the composite fork with attention to different aspects compared
to metal one. In fact, for composite material the areas of coupling with other parts are critical
(headset bearings, stem clamp, gap cap),composite has different impact behavior so for each shock is
important to check fork, finally composite is sensitive to ambient agents (solvents, temperature
over 90°C etc). --Riccardo Carpinacci R&D department, Columbus, Cinelli and 3T
From Look: There is no limitation because carbon has a natural flexibility. It can be used a hundred
years while maintaining the same stiffness. --Ming Tan Look Bicycles
From Reynolds:
After considerable testing and thought on the matter we find the question of "fork life" in terms of
time to be a tough question to answer. Our fatigue testing would indicate that well built composite
forks are far superior to metal forks with cycle counts running hundreds of thousands of cycles
rather than tens of thousands. These tests are also run at much higher loads than metal forks can
withstand further demonstrating the durability of composite materials. Based simply on fatigue life
a well made and properly installed composite fork should last virtually indefinitely if the bike is
not crashed or otherwise abused.
Mike Lopez Reynolds Composites
From Easton: There are two failure modes that could cause a fork to fail, fatigue or impact.
Questions about life span are really questions about fatigue life. How many cycles can a fork
survive before it is tired and worn-out? The good news is the fatigue life of carbon fiber is
immensely more than that of metals. While the writer expresses concern about his carbon fork lasting
as long as a metal component, there is nothing to worry about in terms of fatigue life on a
composite fork.
The most likely cause of failure for a composite fork would be impact damage sustained from
crashing. Most of the time any damage to a fork from a crash will be visible. Cracks can be seen. We
would recommend that the fork be periodically inspected visually at the drop out area and along the
fork legs to look for cracks or depressions in the material. Any fork that shows signs of cracking
should not be ridden and replaced immediately.
In general terms, a component made from carbon fiber will far out-last a component made from metal.
John Harrington Easton Sports
> Anyone have any experience with this type of fork? I'm thinking of buying one, but then someone
> told me they break easily.
>
> Any feedback appreciated.
>
> Thanks,
>
> Dave
The consensus seems to be that carbon forks will last a lifetime (even longer than steel) if they
are not crashed.
From Columbus: Carbon forks can be long lasting but one has to take care of other aspects than
metal ones.
A fiber composite material has higher mechanical characteristics than metals (higher tensile
strength, higher fatigue life, higher stiffness) but it has even different behavior due to its "non-
homogeneous nature". This means that the fork project is really a "critical point" for life span,
moreover the final user has to check the composite fork with attention to different aspects compared
to metal one. In fact, for composite material the areas of coupling with other parts are critical
(headset bearings, stem clamp, gap cap),composite has different impact behavior so for each shock is
important to check fork, finally composite is sensitive to ambient agents (solvents, temperature
over 90°C etc). --Riccardo Carpinacci R&D department, Columbus, Cinelli and 3T
From Look: There is no limitation because carbon has a natural flexibility. It can be used a hundred
years while maintaining the same stiffness. --Ming Tan Look Bicycles
From Reynolds:
After considerable testing and thought on the matter we find the question of "fork life" in terms of
time to be a tough question to answer. Our fatigue testing would indicate that well built composite
forks are far superior to metal forks with cycle counts running hundreds of thousands of cycles
rather than tens of thousands. These tests are also run at much higher loads than metal forks can
withstand further demonstrating the durability of composite materials. Based simply on fatigue life
a well made and properly installed composite fork should last virtually indefinitely if the bike is
not crashed or otherwise abused.
Mike Lopez Reynolds Composites
From Easton: There are two failure modes that could cause a fork to fail, fatigue or impact.
Questions about life span are really questions about fatigue life. How many cycles can a fork
survive before it is tired and worn-out? The good news is the fatigue life of carbon fiber is
immensely more than that of metals. While the writer expresses concern about his carbon fork lasting
as long as a metal component, there is nothing to worry about in terms of fatigue life on a
composite fork.
The most likely cause of failure for a composite fork would be impact damage sustained from
crashing. Most of the time any damage to a fork from a crash will be visible. Cracks can be seen. We
would recommend that the fork be periodically inspected visually at the drop out area and along the
fork legs to look for cracks or depressions in the material. Any fork that shows signs of cracking
should not be ridden and replaced immediately.
In general terms, a component made from carbon fiber will far out-last a component made from metal.
John Harrington Easton Sports
A
Appkiller
Guest
Wait 'til you feel the difference that reticular titanium mesh makes! Faster than any other fork,
with a combination of extreme lateral stiffness, vertical compliance, and absorption of high
frequency road buzz that create a fork unmatched in its performance!
Listen to the unsolicited testimony from our riders:
"You are just a fred. But if you get this fork, I may not knock you off your bike as I pass you."
- Fabrizzio Mazzoleni
"Go Fabs, go!"
- Ryan Cousineau
"I wish I could come up with a good troll for this post."
- F. Golightly
"A haiku:
Carbon fork Titanium mesh Reticular the ad said Faster, in my head"
- Carl Fogel
"<insert your favorite bizarre rant here>"
- That freaky dude who puts up those freaky posts no one understands (you know who I am
talking about)
App
with a combination of extreme lateral stiffness, vertical compliance, and absorption of high
frequency road buzz that create a fork unmatched in its performance!
Listen to the unsolicited testimony from our riders:
"You are just a fred. But if you get this fork, I may not knock you off your bike as I pass you."
- Fabrizzio Mazzoleni
"Go Fabs, go!"
- Ryan Cousineau
"I wish I could come up with a good troll for this post."
- F. Golightly
"A haiku:
Carbon fork Titanium mesh Reticular the ad said Faster, in my head"
- Carl Fogel
"<insert your favorite bizarre rant here>"
- That freaky dude who puts up those freaky posts no one understands (you know who I am
talking about)
App
J
Jim Beam
Guest
excellent!
Rik O'Shea wrote:
> [email protected] (UMTERP) wrote in message news:<[email protected]>...
>
>>Anyone have any experience with this type of fork? I'm thinking of buying one, but then someone
>>told me they break easily.
>>
>>Any feedback appreciated.
>>
>>Thanks,
>>
>>Dave
>
>
> The consensus seems to be that carbon forks will last a lifetime (even longer than steel) if they
> are not crashed.
>
> From Columbus: Carbon forks can be long lasting but one has to take care of other aspects than
> metal ones.
>
> A fiber composite material has higher mechanical characteristics than metals (higher tensile
> strength, higher fatigue life, higher stiffness) but it has even different behavior due to its "non-
> homogeneous nature". This means that the fork project is really a "critical point" for life span,
> moreover the final user has to check the composite fork with attention to different aspects
> compared to metal one. In fact, for composite material the areas of coupling with other parts are
> critical (headset bearings, stem clamp, gap cap),composite has different impact behavior so for
> each shock is important to check fork, finally composite is sensitive to ambient agents (solvents,
> temperature over 90°C etc). --Riccardo Carpinacci R&D department, Columbus, Cinelli and 3T
>
> From Look: There is no limitation because carbon has a natural flexibility. It can be used a
> hundred years while maintaining the same stiffness. --Ming Tan Look Bicycles
>
> From Reynolds:
>
> After considerable testing and thought on the matter we find the question of "fork life" in terms
> of time to be a tough question to answer. Our fatigue testing would indicate that well built
> composite forks are far superior to metal forks with cycle counts running hundreds of thousands of
> cycles rather than tens of thousands. These tests are also run at much higher loads than metal
> forks can withstand further demonstrating the durability of composite materials. Based simply on
> fatigue life a well made and properly installed composite fork should last virtually indefinitely
> if the bike is not crashed or otherwise abused.
>
> Mike Lopez Reynolds Composites
>
> From Easton: There are two failure modes that could cause a fork to fail, fatigue or impact.
> Questions about life span are really questions about fatigue life. How many cycles can a fork
> survive before it is tired and worn-out? The good news is the fatigue life of carbon fiber is
> immensely more than that of metals. While the writer expresses concern about his carbon fork
> lasting as long as a metal component, there is nothing to worry about in terms of fatigue life on
> a composite fork.
>
> The most likely cause of failure for a composite fork would be impact damage sustained from
> crashing. Most of the time any damage to a fork from a crash will be visible. Cracks can be seen.
> We would recommend that the fork be periodically inspected visually at the drop out area and along
> the fork legs to look for cracks or depressions in the material. Any fork that shows signs of
> cracking should not be ridden and replaced immediately.
>
> In general terms, a component made from carbon fiber will far out-last a component made
> from metal.
>
> John Harrington Easton Sports
Rik O'Shea wrote:
> [email protected] (UMTERP) wrote in message news:<[email protected]>...
>
>>Anyone have any experience with this type of fork? I'm thinking of buying one, but then someone
>>told me they break easily.
>>
>>Any feedback appreciated.
>>
>>Thanks,
>>
>>Dave
>
>
> The consensus seems to be that carbon forks will last a lifetime (even longer than steel) if they
> are not crashed.
>
> From Columbus: Carbon forks can be long lasting but one has to take care of other aspects than
> metal ones.
>
> A fiber composite material has higher mechanical characteristics than metals (higher tensile
> strength, higher fatigue life, higher stiffness) but it has even different behavior due to its "non-
> homogeneous nature". This means that the fork project is really a "critical point" for life span,
> moreover the final user has to check the composite fork with attention to different aspects
> compared to metal one. In fact, for composite material the areas of coupling with other parts are
> critical (headset bearings, stem clamp, gap cap),composite has different impact behavior so for
> each shock is important to check fork, finally composite is sensitive to ambient agents (solvents,
> temperature over 90°C etc). --Riccardo Carpinacci R&D department, Columbus, Cinelli and 3T
>
> From Look: There is no limitation because carbon has a natural flexibility. It can be used a
> hundred years while maintaining the same stiffness. --Ming Tan Look Bicycles
>
> From Reynolds:
>
> After considerable testing and thought on the matter we find the question of "fork life" in terms
> of time to be a tough question to answer. Our fatigue testing would indicate that well built
> composite forks are far superior to metal forks with cycle counts running hundreds of thousands of
> cycles rather than tens of thousands. These tests are also run at much higher loads than metal
> forks can withstand further demonstrating the durability of composite materials. Based simply on
> fatigue life a well made and properly installed composite fork should last virtually indefinitely
> if the bike is not crashed or otherwise abused.
>
> Mike Lopez Reynolds Composites
>
> From Easton: There are two failure modes that could cause a fork to fail, fatigue or impact.
> Questions about life span are really questions about fatigue life. How many cycles can a fork
> survive before it is tired and worn-out? The good news is the fatigue life of carbon fiber is
> immensely more than that of metals. While the writer expresses concern about his carbon fork
> lasting as long as a metal component, there is nothing to worry about in terms of fatigue life on
> a composite fork.
>
> The most likely cause of failure for a composite fork would be impact damage sustained from
> crashing. Most of the time any damage to a fork from a crash will be visible. Cracks can be seen.
> We would recommend that the fork be periodically inspected visually at the drop out area and along
> the fork legs to look for cracks or depressions in the material. Any fork that shows signs of
> cracking should not be ridden and replaced immediately.
>
> In general terms, a component made from carbon fiber will far out-last a component made
> from metal.
>
> John Harrington Easton Sports
C
Carl Fogel
Guest
[email protected] (Rik O'Shea) wrote in message news:<[email protected]>...
> [email protected] (UMTERP) wrote in message news:<[email protected]>...
> > Anyone have any experience with this type of fork? I'm thinking of buying one, but then someone
> > told me they break easily.
> >
> > Any feedback appreciated.
> >
> > Thanks,
> >
> > Dave
>
> The consensus seems to be that carbon forks will last a lifetime (even longer than steel) if they
> are not crashed.
[regretfully snip several detailed opinions about carbon forks that Rik took some time and trouble
to collect and that I read with interest]
Dear Rik,
I think that the original question was whether these carbon Columbus Muscle Forks "break easily,"
not whether carbon forks in general last a long time as long as you don't break them in a crash.
That is, what happens if you pop a pair of these Columbus Muscle Forks in a vise and whack 'em with
a hammer to simulate a crash or wiggle 'em to mimic ordinary riding stresses? Do the Columbus forks
bust more easily than other brands of carbon forks or any kind of metal forks?
Like Dave, I appreciate your feedback, which suggests that carbon forks in general survive ordinary
riding (but don't crash). That may be what Dave wanted to know, but he might have been wondering if
these Columbus Muscles forks are the Ford Pinto of the carbon fork world, too thin, too fragile, or
somehow badly designed.
Carl Fogel
> [email protected] (UMTERP) wrote in message news:<[email protected]>...
> > Anyone have any experience with this type of fork? I'm thinking of buying one, but then someone
> > told me they break easily.
> >
> > Any feedback appreciated.
> >
> > Thanks,
> >
> > Dave
>
> The consensus seems to be that carbon forks will last a lifetime (even longer than steel) if they
> are not crashed.
[regretfully snip several detailed opinions about carbon forks that Rik took some time and trouble
to collect and that I read with interest]
Dear Rik,
I think that the original question was whether these carbon Columbus Muscle Forks "break easily,"
not whether carbon forks in general last a long time as long as you don't break them in a crash.
That is, what happens if you pop a pair of these Columbus Muscle Forks in a vise and whack 'em with
a hammer to simulate a crash or wiggle 'em to mimic ordinary riding stresses? Do the Columbus forks
bust more easily than other brands of carbon forks or any kind of metal forks?
Like Dave, I appreciate your feedback, which suggests that carbon forks in general survive ordinary
riding (but don't crash). That may be what Dave wanted to know, but he might have been wondering if
these Columbus Muscles forks are the Ford Pinto of the carbon fork world, too thin, too fragile, or
somehow badly designed.
Carl Fogel
C
Carl Fogel
Guest
[email protected] (Appkiller) wrote in message news:<[email protected]>...
[snip]
> - That freaky dude who puts up those freaky posts no one understands (you know who I am talking
> about)
>
> App
Dear App,
Oooh, a literary guessing game! I should be good at this . . .
Jobst Brandt?
Sheldon Brown?
Chalo Colina?
Wait, it's on the tip of my tongue--
Gong!
[snip]
> - That freaky dude who puts up those freaky posts no one understands (you know who I am talking
> about)
>
> App
Dear App,
Oooh, a literary guessing game! I should be good at this . . .
Jobst Brandt?
Sheldon Brown?
Chalo Colina?
Wait, it's on the tip of my tongue--
Gong!
R
Rik O'Shea
Guest
[email protected] (Carl Fogel) wrote in message news:<[email protected]>...
> Dear Rik,
>
> I think that the original question was whether these carbon Columbus Muscle Forks "break easily,"
> not whether carbon forks in general last a long time as long as you don't break them in a crash.
>
> That is, what happens if you pop a pair of these Columbus Muscle Forks in a vise and whack 'em
> with a hammer to simulate a crash or wiggle 'em to mimic ordinary riding stresses? Do the Columbus
> forks bust more easily than other brands of carbon forks or any kind of metal forks?
>
> Like Dave, I appreciate your feedback, which suggests that carbon forks in general survive
> ordinary riding (but don't crash). That may be what Dave wanted to know, but he might have been
> wondering if these Columbus Muscles forks are the Ford Pinto of the carbon fork world, too thin,
> too fragile, or somehow badly designed.
>
> Carl Fogel
The following is from http://www.framebuilding.com/carbon%20forks.htm although I dont specifically
know how it compares to the testing performed on carbon forks from other manufactures. ASTM
standards call for a load of 170 lbs. applied perpendicular to the steering axis, both pushing and
pulling for 50,000 cycles without failure. The information below seems to suggest that the Columbus
forks exceed this.
-----------0---------
Columbus carbon forks are produced in accordance with ISO 9000. All forks are marked and their
history can be traced. The tests include destruction testing and are performed on finished product
samples. They are very severe:
* Frontal and side strength test: A load of 200 N is first applied to the frontal part and then
to the side part of the fork. The flex is measured on each occasion and this must not exceed a
set value.
* Shock Test: A mass of 250 N is dropped from a height of 430mm on a properly restrained fork.
In order to pass the test the fork must resist without breakage or residual deformation.
* Static Test: A load of 200 N is applied to the frontal part for 1 minute. In order to pass the
test the fork must resist without breakage or deformation.
* Fatigue Test: During this test an alternate force of +-600 N is applied. In order to pass this
test the fork must resist for 150,000 cycles without breaking.
> Dear Rik,
>
> I think that the original question was whether these carbon Columbus Muscle Forks "break easily,"
> not whether carbon forks in general last a long time as long as you don't break them in a crash.
>
> That is, what happens if you pop a pair of these Columbus Muscle Forks in a vise and whack 'em
> with a hammer to simulate a crash or wiggle 'em to mimic ordinary riding stresses? Do the Columbus
> forks bust more easily than other brands of carbon forks or any kind of metal forks?
>
> Like Dave, I appreciate your feedback, which suggests that carbon forks in general survive
> ordinary riding (but don't crash). That may be what Dave wanted to know, but he might have been
> wondering if these Columbus Muscles forks are the Ford Pinto of the carbon fork world, too thin,
> too fragile, or somehow badly designed.
>
> Carl Fogel
The following is from http://www.framebuilding.com/carbon%20forks.htm although I dont specifically
know how it compares to the testing performed on carbon forks from other manufactures. ASTM
standards call for a load of 170 lbs. applied perpendicular to the steering axis, both pushing and
pulling for 50,000 cycles without failure. The information below seems to suggest that the Columbus
forks exceed this.
-----------0---------
Columbus carbon forks are produced in accordance with ISO 9000. All forks are marked and their
history can be traced. The tests include destruction testing and are performed on finished product
samples. They are very severe:
* Frontal and side strength test: A load of 200 N is first applied to the frontal part and then
to the side part of the fork. The flex is measured on each occasion and this must not exceed a
set value.
* Shock Test: A mass of 250 N is dropped from a height of 430mm on a properly restrained fork.
In order to pass the test the fork must resist without breakage or residual deformation.
* Static Test: A load of 200 N is applied to the frontal part for 1 minute. In order to pass the
test the fork must resist without breakage or deformation.
* Fatigue Test: During this test an alternate force of +-600 N is applied. In order to pass this
test the fork must resist for 150,000 cycles without breaking.
C
Carl Fogel
Guest
[email protected] (Rik O'Shea) wrote in message news:<[email protected]>...
> [email protected] (Carl Fogel) wrote in message
> news:<[email protected]>...
>
> > Dear Rik,
> >
> > I think that the original question was whether these carbon Columbus Muscle Forks "break
> > easily," not whether carbon forks in general last a long time as long as you don't break them in
> > a crash.
> >
> > That is, what happens if you pop a pair of these Columbus Muscle Forks in a vise and whack 'em
> > with a hammer to simulate a crash or wiggle 'em to mimic ordinary riding stresses? Do the
> > Columbus forks bust more easily than other brands of carbon forks or any kind of metal forks?
> >
> > Like Dave, I appreciate your feedback, which suggests that carbon forks in general survive
> > ordinary riding (but don't crash). That may be what Dave wanted to know, but he might have been
> > wondering if these Columbus Muscles forks are the Ford Pinto of the carbon fork world, too thin,
> > too fragile, or somehow badly designed.
> >
> > Carl Fogel
>
> The following is from http://www.framebuilding.com/carbon%20forks.htm although I dont specifically
> know how it compares to the testing performed on carbon forks from other manufactures. ASTM
> standards call for a load of 170 lbs. applied perpendicular to the steering axis, both pushing and
> pulling for 50,000 cycles without failure. The information below seems to suggest that the
> Columbus forks exceed this.
>
> -----------0---------
>
> Columbus carbon forks are produced in accordance with ISO 9000. All forks are marked and their
> history can be traced. The tests include destruction testing and are performed on finished product
> samples. They are very severe:
>
> * Frontal and side strength test: A load of 200 N is first applied to the frontal part and
> then to the side part of the fork. The flex is measured on each occasion and this must not
> exceed a set value.
> * Shock Test: A mass of 250 N is dropped from a height of 430mm on a properly restrained fork.
> In order to pass the test the fork must resist without breakage or residual deformation.
> * Static Test: A load of 200 N is applied to the frontal part for 1 minute. In order to pass
> the test the fork must resist without breakage or deformation.
> * Fatigue Test: During this test an alternate force of +-600 N is applied. In order to pass
> this test the fork must resist for 150,000 cycles without breaking.
Dear Rik,
The site that you found seems to be the Columbus Carbon parts web site:
http://www.framebuilding.com/carbon%20forks.htm
I found it fascinatinng. I'm ignorant about forks and materials, but I'm wary of what seems like
confused marketing hype:
"Carbon fibre as a material is 4 times more resistant than steel and 8 times more resistant than
aluminium. Its versatility and directionality allows Columbus designers to modulate the section and
form of the fork blades to satisfy all design criteria, without compromise or limitation. The
Columbus composite fork blades have been realized by overlapping 15 layers of T-700 aerospace carbon
fibre and then covering this externally with a layer of High Modulus Carbon fibre, which is 20%
lighter and 10% more resistant than T-700. Additionally the full carbon fork, MUSCLE, also includes
a special reticular fabric in titanium called 'Ti Mesh titanium net'. This has a considerable
damping effect on high frequency vibrations within the fork, such as those produced by irregular
ground surfaces. Super Muscle includes Kevlar and Nickel for improved weight saving while
maintaining strength and shock resistance."
What do they mean by "resistant"? Strength in compression?
Why use 15 inner layers of inferior T-700 and only one outer layer of the good stuff, which is "20%
lighter and 10% more resistant"?
(It sounds as if they could use the good stuff and make a 10% stronger fork that would be
20% lighter.)
Why does a carbon fork, often claimed to damp vibration better than metal, need a layer of metal
mesh to damp vibrations?
How does including Kevlar and nickel in the Super Muscle Fork save weight while maintaining
strength? Isn't nickel a denser and weaker metal than the titanium used in the plain muscle fork?
(The titanium in the plain Muscle Fork has roughly 8 times nickel's yield strength and 33% more
tensile strength than nickel, a weaker metal that's twice as dense as titanium--8,800 kg/cubic-meter
versus 4,500 kg/cubic-meter:
http://www.simetric.co.uk/si_metals.htm
This density site also lists manure at 400 kg/cubic meter, a figure that may apply to some of the
Columbus site's explanations.)
Apart from such technical mysteries, it still sounds as if we don't want to crash such forks,
which was the consensus of the experts in your previous post. I've gathered elsewhere that severe
carbon damage can be invisible to the naked eye, while metal tends to bend and reveal its
impending failure.
The ISO 9000 "shock test" mentioned on the site sounds as if a 670-pound weight is dropped 17 inches
onto an upright fork.
While surviving this thump sounds impressive, ordinary BMX and mountain bikes routinely drop 250
pounds onto the front and rear from considerably more than a foot and a half, so I'm not sure
how well this simulates a fork-damaging crash, which typically involves the sideways force of
ramming something. Like a leg-bone, a fork resists impacts from above that would easily break it
from the side.
Again, I do appreciate the effort that you put into finding this Columbus site, which certainly
indicates that the Muscle fork and its big brother both pass the basic kinds of tests that I was
wondering about and that might be what the original poster wanted to know--the ISO standard suggests
that the Carbon Muscle fork meets detailed fork standards, so it ought to be fairly reliable, no
matter what the marketing people are babbling.
So thanks--it's awfully nice of you to cater to my curiosity by finding that site.
Carl Fogel
> [email protected] (Carl Fogel) wrote in message
> news:<[email protected]>...
>
> > Dear Rik,
> >
> > I think that the original question was whether these carbon Columbus Muscle Forks "break
> > easily," not whether carbon forks in general last a long time as long as you don't break them in
> > a crash.
> >
> > That is, what happens if you pop a pair of these Columbus Muscle Forks in a vise and whack 'em
> > with a hammer to simulate a crash or wiggle 'em to mimic ordinary riding stresses? Do the
> > Columbus forks bust more easily than other brands of carbon forks or any kind of metal forks?
> >
> > Like Dave, I appreciate your feedback, which suggests that carbon forks in general survive
> > ordinary riding (but don't crash). That may be what Dave wanted to know, but he might have been
> > wondering if these Columbus Muscles forks are the Ford Pinto of the carbon fork world, too thin,
> > too fragile, or somehow badly designed.
> >
> > Carl Fogel
>
> The following is from http://www.framebuilding.com/carbon%20forks.htm although I dont specifically
> know how it compares to the testing performed on carbon forks from other manufactures. ASTM
> standards call for a load of 170 lbs. applied perpendicular to the steering axis, both pushing and
> pulling for 50,000 cycles without failure. The information below seems to suggest that the
> Columbus forks exceed this.
>
> -----------0---------
>
> Columbus carbon forks are produced in accordance with ISO 9000. All forks are marked and their
> history can be traced. The tests include destruction testing and are performed on finished product
> samples. They are very severe:
>
> * Frontal and side strength test: A load of 200 N is first applied to the frontal part and
> then to the side part of the fork. The flex is measured on each occasion and this must not
> exceed a set value.
> * Shock Test: A mass of 250 N is dropped from a height of 430mm on a properly restrained fork.
> In order to pass the test the fork must resist without breakage or residual deformation.
> * Static Test: A load of 200 N is applied to the frontal part for 1 minute. In order to pass
> the test the fork must resist without breakage or deformation.
> * Fatigue Test: During this test an alternate force of +-600 N is applied. In order to pass
> this test the fork must resist for 150,000 cycles without breaking.
Dear Rik,
The site that you found seems to be the Columbus Carbon parts web site:
http://www.framebuilding.com/carbon%20forks.htm
I found it fascinatinng. I'm ignorant about forks and materials, but I'm wary of what seems like
confused marketing hype:
"Carbon fibre as a material is 4 times more resistant than steel and 8 times more resistant than
aluminium. Its versatility and directionality allows Columbus designers to modulate the section and
form of the fork blades to satisfy all design criteria, without compromise or limitation. The
Columbus composite fork blades have been realized by overlapping 15 layers of T-700 aerospace carbon
fibre and then covering this externally with a layer of High Modulus Carbon fibre, which is 20%
lighter and 10% more resistant than T-700. Additionally the full carbon fork, MUSCLE, also includes
a special reticular fabric in titanium called 'Ti Mesh titanium net'. This has a considerable
damping effect on high frequency vibrations within the fork, such as those produced by irregular
ground surfaces. Super Muscle includes Kevlar and Nickel for improved weight saving while
maintaining strength and shock resistance."
What do they mean by "resistant"? Strength in compression?
Why use 15 inner layers of inferior T-700 and only one outer layer of the good stuff, which is "20%
lighter and 10% more resistant"?
(It sounds as if they could use the good stuff and make a 10% stronger fork that would be
20% lighter.)
Why does a carbon fork, often claimed to damp vibration better than metal, need a layer of metal
mesh to damp vibrations?
How does including Kevlar and nickel in the Super Muscle Fork save weight while maintaining
strength? Isn't nickel a denser and weaker metal than the titanium used in the plain muscle fork?
(The titanium in the plain Muscle Fork has roughly 8 times nickel's yield strength and 33% more
tensile strength than nickel, a weaker metal that's twice as dense as titanium--8,800 kg/cubic-meter
versus 4,500 kg/cubic-meter:
http://www.simetric.co.uk/si_metals.htm
This density site also lists manure at 400 kg/cubic meter, a figure that may apply to some of the
Columbus site's explanations.)
Apart from such technical mysteries, it still sounds as if we don't want to crash such forks,
which was the consensus of the experts in your previous post. I've gathered elsewhere that severe
carbon damage can be invisible to the naked eye, while metal tends to bend and reveal its
impending failure.
The ISO 9000 "shock test" mentioned on the site sounds as if a 670-pound weight is dropped 17 inches
onto an upright fork.
While surviving this thump sounds impressive, ordinary BMX and mountain bikes routinely drop 250
pounds onto the front and rear from considerably more than a foot and a half, so I'm not sure
how well this simulates a fork-damaging crash, which typically involves the sideways force of
ramming something. Like a leg-bone, a fork resists impacts from above that would easily break it
from the side.
Again, I do appreciate the effort that you put into finding this Columbus site, which certainly
indicates that the Muscle fork and its big brother both pass the basic kinds of tests that I was
wondering about and that might be what the original poster wanted to know--the ISO standard suggests
that the Carbon Muscle fork meets detailed fork standards, so it ought to be fairly reliable, no
matter what the marketing people are babbling.
So thanks--it's awfully nice of you to cater to my curiosity by finding that site.
Carl Fogel
J
Jim Beam
Guest
Carl Fogel wrote: <snip>
> Why does a carbon fork, often claimed to damp vibration better than metal, need a layer of metal
> mesh to damp vibrations?
>
> How does including Kevlar and nickel in the Super Muscle Fork save weight while maintaining
> strength? Isn't nickel a denser and weaker metal than the titanium used in the plain muscle fork?
good questions! nickel alloys are not necessarily weak, often quite the reverse, but they are
/cheaper/ than ti!!!
to be honest, i have a hard time filtering out any tech from the marketing with that columbus blurb,
but as i understand it, the reason composites are good for vibration is because the fibers are
embedded in a polymer matrix. the modulus of the polymer is very low and for small deformation
amplitudes, you're riding on polymer, not high modulus graphite.
what a mesh would do is effectively provide a large volume of polymer between high density layers
of graphite fibers and therefore provide a zone of "insulation" between different regions of the
component. so, provided that "insulation" layer of polymer can be persuaded to remain intact at
high load, and the mesh would hopefully have this effect as well as separation, then that could be
the reason. but for the definitive answer, you'll need to ask someone with more composites
experience than i.
jb
> Why does a carbon fork, often claimed to damp vibration better than metal, need a layer of metal
> mesh to damp vibrations?
>
> How does including Kevlar and nickel in the Super Muscle Fork save weight while maintaining
> strength? Isn't nickel a denser and weaker metal than the titanium used in the plain muscle fork?
good questions! nickel alloys are not necessarily weak, often quite the reverse, but they are
/cheaper/ than ti!!!
to be honest, i have a hard time filtering out any tech from the marketing with that columbus blurb,
but as i understand it, the reason composites are good for vibration is because the fibers are
embedded in a polymer matrix. the modulus of the polymer is very low and for small deformation
amplitudes, you're riding on polymer, not high modulus graphite.
what a mesh would do is effectively provide a large volume of polymer between high density layers
of graphite fibers and therefore provide a zone of "insulation" between different regions of the
component. so, provided that "insulation" layer of polymer can be persuaded to remain intact at
high load, and the mesh would hopefully have this effect as well as separation, then that could be
the reason. but for the definitive answer, you'll need to ask someone with more composites
experience than i.
jb
C
Carl Fogel
Guest
jim beam <[email protected]> wrote in message news:<[email protected]>...
> Carl Fogel wrote: <snip>
>
> > Why does a carbon fork, often claimed to damp vibration better than metal, need a layer of metal
> > mesh to damp vibrations?
> >
> > How does including Kevlar and nickel in the Super Muscle Fork save weight while
> > maintaining strength? Isn't nickel a denser and weaker metal than the titanium used in the
> > plain muscle fork?
>
> good questions! nickel alloys are not necessarily weak, often quite the reverse, but they are
> /cheaper/ than ti!!!
>
> to be honest, i have a hard time filtering out any tech from the marketing with that columbus
> blurb, but as i understand it, the reason composites are good for vibration is because the fibers
> are embedded in a polymer matrix. the modulus of the polymer is very low and for small deformation
> amplitudes, you're riding on polymer, not high modulus graphite.
>
> what a mesh would do is effectively provide a large volume of polymer between high density layers
> of graphite fibers and therefore provide a zone of "insulation" between different regions of the
> component. so, provided that "insulation" layer of polymer can be persuaded to remain intact at
> high load, and the mesh would hopefully have this effect as well as separation, then that could be
> the reason. but for the definitive answer, you'll need to ask someone with more composites
> experience than i.
>
> jb
Dear Jim,
Most of that went over my head (not your fault, I have lots of clearance).
But the Columbus site seems to say that they use cheaper nickel mesh (I found "carbon nickel"
mentioned) to make the more expensive version of the fork--which somehow ends up being lighter than
the cheaper titanium mesh version.
cheaper plain muscle fork = titanium = 380 grams expensive super muscle fork = nickel-carbon
= 340 grams
I browsed a bit more and found this page describing the Super Muscle Fork further on the same site:
http://www.framebuilding.com/what.htm
"In the fork column, Columbus has inserted Kevlar layers, which through their ability to resist cuts
and abrasions, reduce the risk of cuts caused by the clamps of the handlebar stem, which are
particularly sharp."
Again, I'm wary. Perhaps Kevlar resists cutting better than plain carbon fiber, but I seem recall
reading that Kevlar is usually cut with ordinary scissors--its virtues do not include any great
resistance to cuts.
There must be some prices somewhere, but I didn't find any when I looked.
Carl Fogel
> Carl Fogel wrote: <snip>
>
> > Why does a carbon fork, often claimed to damp vibration better than metal, need a layer of metal
> > mesh to damp vibrations?
> >
> > How does including Kevlar and nickel in the Super Muscle Fork save weight while
> > maintaining strength? Isn't nickel a denser and weaker metal than the titanium used in the
> > plain muscle fork?
>
> good questions! nickel alloys are not necessarily weak, often quite the reverse, but they are
> /cheaper/ than ti!!!
>
> to be honest, i have a hard time filtering out any tech from the marketing with that columbus
> blurb, but as i understand it, the reason composites are good for vibration is because the fibers
> are embedded in a polymer matrix. the modulus of the polymer is very low and for small deformation
> amplitudes, you're riding on polymer, not high modulus graphite.
>
> what a mesh would do is effectively provide a large volume of polymer between high density layers
> of graphite fibers and therefore provide a zone of "insulation" between different regions of the
> component. so, provided that "insulation" layer of polymer can be persuaded to remain intact at
> high load, and the mesh would hopefully have this effect as well as separation, then that could be
> the reason. but for the definitive answer, you'll need to ask someone with more composites
> experience than i.
>
> jb
Dear Jim,
Most of that went over my head (not your fault, I have lots of clearance).
But the Columbus site seems to say that they use cheaper nickel mesh (I found "carbon nickel"
mentioned) to make the more expensive version of the fork--which somehow ends up being lighter than
the cheaper titanium mesh version.
cheaper plain muscle fork = titanium = 380 grams expensive super muscle fork = nickel-carbon
= 340 grams
I browsed a bit more and found this page describing the Super Muscle Fork further on the same site:
http://www.framebuilding.com/what.htm
"In the fork column, Columbus has inserted Kevlar layers, which through their ability to resist cuts
and abrasions, reduce the risk of cuts caused by the clamps of the handlebar stem, which are
particularly sharp."
Again, I'm wary. Perhaps Kevlar resists cutting better than plain carbon fiber, but I seem recall
reading that Kevlar is usually cut with ordinary scissors--its virtues do not include any great
resistance to cuts.
There must be some prices somewhere, but I didn't find any when I looked.
Carl Fogel
J
Jim Beam
Guest
Carl Fogel wrote:
> But the Columbus site seems to say that they use cheaper nickel mesh (I found "carbon nickel"
> mentioned) to make the more expensive version of the fork--which somehow ends up being lighter
> than the cheaper titanium mesh version.
>
> cheaper plain muscle fork = titanium = 380 grams expensive super muscle fork = nickel-carbon =
> 340 grams
just don't know. some nickel alloys are quite exotic & expensive, but those are usually for high
temperature applications. don't know the specifics here, and honestly still can't tell you why
nickel would be used.
>
> I browsed a bit more and found this page describing the Super Muscle Fork further on the
> same site:
>
> http://www.framebuilding.com/what.htm
>
> "In the fork column, Columbus has inserted Kevlar layers, which through their ability to resist
> cuts and abrasions, reduce the risk of cuts caused by the clamps of the handlebar stem, which are
> particularly sharp."
>
> Again, I'm wary. Perhaps Kevlar resists cutting better than plain carbon fiber, but I seem recall
> reading that Kevlar is usually cut with ordinary scissors--its virtues do not include any great
> resistance to cuts.
as nicely stated here;
http://plastics.about.com/library/weekly/aa050597.htm
kevlar is used to protect carbon composites against catastrophic failure, but one of the only two
failed carbon handlebars i've seen was woven with kevlar, so who knows how this is supposed to work
in practice.
while looking for that page, i got totally sidetracked by this:
http://www.ideafinder.com/history/inventors/kwolek.htm
do you have any tech-inclined daughters you want to inspire?
jb
> But the Columbus site seems to say that they use cheaper nickel mesh (I found "carbon nickel"
> mentioned) to make the more expensive version of the fork--which somehow ends up being lighter
> than the cheaper titanium mesh version.
>
> cheaper plain muscle fork = titanium = 380 grams expensive super muscle fork = nickel-carbon =
> 340 grams
just don't know. some nickel alloys are quite exotic & expensive, but those are usually for high
temperature applications. don't know the specifics here, and honestly still can't tell you why
nickel would be used.
>
> I browsed a bit more and found this page describing the Super Muscle Fork further on the
> same site:
>
> http://www.framebuilding.com/what.htm
>
> "In the fork column, Columbus has inserted Kevlar layers, which through their ability to resist
> cuts and abrasions, reduce the risk of cuts caused by the clamps of the handlebar stem, which are
> particularly sharp."
>
> Again, I'm wary. Perhaps Kevlar resists cutting better than plain carbon fiber, but I seem recall
> reading that Kevlar is usually cut with ordinary scissors--its virtues do not include any great
> resistance to cuts.
as nicely stated here;
http://plastics.about.com/library/weekly/aa050597.htm
kevlar is used to protect carbon composites against catastrophic failure, but one of the only two
failed carbon handlebars i've seen was woven with kevlar, so who knows how this is supposed to work
in practice.
while looking for that page, i got totally sidetracked by this:
http://www.ideafinder.com/history/inventors/kwolek.htm
do you have any tech-inclined daughters you want to inspire?
jb
C
Carl Fogel
Guest
jim beam <[email protected]> wrote in message news:<u38Hb.2658$%[email protected]>...
> Carl Fogel wrote:
[snip]
> > I browsed a bit more and found this page describing the Super Muscle Fork further on the
> > same site:
> >
> > http://www.framebuilding.com/what.htm
> >
> > "In the fork column, Columbus has inserted Kevlar layers, which through their ability to resist
> > cuts and abrasions, reduce the risk of cuts caused by the clamps of the handlebar stem, which
> > are particularly sharp."
> >
> > Again, I'm wary. Perhaps Kevlar resists cutting better than plain carbon fiber, but I seem
> > recall reading that Kevlar is usually cut with ordinary scissors--its virtues do not include any
> > great resistance to cuts.
>
> as nicely stated here;
>
> http://plastics.about.com/library/weekly/aa050597.htm
>
> kevlar is used to protect carbon composites against catastrophic failure, but one of the only two
> failed carbon handlebars i've seen was woven with kevlar, so who knows how this is supposed to
> work in practice.
>
> while looking for that page, i got totally sidetracked by this:
>
> http://www.ideafinder.com/history/inventors/kwolek.htm
>
> do you have any tech-inclined daughters you want to inspire?
>
> jb
Dear Jim,
A Google Groups search for kevlar and scissors reassured me that I hadn't imagined reading that
Kevlar can be cut with scissors, but casts doubt on the simplicity of the situation.
The web site that you suggested indicates special ceramic scissors are used to cut Kevlar, yet a
Google Groups search for "kevlar" and "scissors" shows posts and apparent controversy going back to
1993 about how hard the stuff is to cut:
Re: Clinchers.. (Kevlar - a point to note). ... As for the knife through the vest story, have you
tried cutting kevlar fiber? It's really tough stuff and not easily cut with a sharp knife or
scissors. ... rec.bicycles.tech - Aug 11, 2002 by Bill - View Thread (43 articles)
Re: Recovering a seat ... of staple. - Trim the excess with scissors where you can, then with a
knife. It's a little tricky with Kevlar ! - Womens saddles ... rec.bicycles.tech - Jul 1, 1998 by
Andy Dingley - View Thread (7 articles)
Re: experienced with composite materials? ... Oh, and you'll need a good pair of scissors or knife
(professionals use ceramic scissors and knives) to cut anything with kevlar in - and they'll still
blunt ... rec.bicycles.tech - Sep 11, 1997 by Chris McSweeny - View Thread (3 articles)
Re: Anyone used Specialized Armadillo? ... The fibers were cut. Kevlar is tough but not
invulnerable. It can be cut with sharp scissors, and the edges on broken glass are EXTREMELY sharp.
... rec.bicycles.tech - Dec 28, 1996 by Ray Bowman - View Thread (18 articles)
Re: Hollow (cylindrical) spokes? ... I guess you have never played the ancient game of "Paper-Scissor-
Rock" If I can cut Kevlar with household scissors, it isn't as hard as steel and the ...
rec.bicycles.tech - Feb 4, 1995 by Jobst Brandt - View Thread (18 articles)
Re: strength of kevlar ... It has worked admirably. Kevlar can be cut with ordinary scissors more
easily than fiber glass. Could someone elaborate on this, with some numbers? .... ...
rec.bicycles.tech - Jan 30, 1995 by Composites Lab - View Thread (3 articles)
Re: Kevlar, Schmevlar ... Kevlar. For instance, ordinary steel scissors cut Kevlar cloth easily as
does glass even though it can stop bullets. Kevlar has ... rec.bicycles.tech - Jul 24, 1993 by Jobst
Brandt - View Thread (7 articles)
Possibly the Kevlar site is a little ambiguous? That is, I'm not sure when I re-read it whether they
mean that Kevlar is difficult to cut or drill at all (resistant) or difficult to cut or drill neatly
without fraying (messy).
"Finally, Kevlar is also very difficult to cut. You will need special scissors for cutting dry
fabric or prepreg, and special drill bits for drilling cured laminates. Cutting of cured laminates
without fraying is very difficult."
http://plastics.about.com/library/weekly/aa050597.htm
As for inspiring daughters with the story of the inventor of Kevlar, all I have is a pair of saucy
sisters, both of whom need constant stifling just to keep them (and their daughters) in their place.
Carl Fogel
> Carl Fogel wrote:
[snip]
> > I browsed a bit more and found this page describing the Super Muscle Fork further on the
> > same site:
> >
> > http://www.framebuilding.com/what.htm
> >
> > "In the fork column, Columbus has inserted Kevlar layers, which through their ability to resist
> > cuts and abrasions, reduce the risk of cuts caused by the clamps of the handlebar stem, which
> > are particularly sharp."
> >
> > Again, I'm wary. Perhaps Kevlar resists cutting better than plain carbon fiber, but I seem
> > recall reading that Kevlar is usually cut with ordinary scissors--its virtues do not include any
> > great resistance to cuts.
>
> as nicely stated here;
>
> http://plastics.about.com/library/weekly/aa050597.htm
>
> kevlar is used to protect carbon composites against catastrophic failure, but one of the only two
> failed carbon handlebars i've seen was woven with kevlar, so who knows how this is supposed to
> work in practice.
>
> while looking for that page, i got totally sidetracked by this:
>
> http://www.ideafinder.com/history/inventors/kwolek.htm
>
> do you have any tech-inclined daughters you want to inspire?
>
> jb
Dear Jim,
A Google Groups search for kevlar and scissors reassured me that I hadn't imagined reading that
Kevlar can be cut with scissors, but casts doubt on the simplicity of the situation.
The web site that you suggested indicates special ceramic scissors are used to cut Kevlar, yet a
Google Groups search for "kevlar" and "scissors" shows posts and apparent controversy going back to
1993 about how hard the stuff is to cut:
Re: Clinchers.. (Kevlar - a point to note). ... As for the knife through the vest story, have you
tried cutting kevlar fiber? It's really tough stuff and not easily cut with a sharp knife or
scissors. ... rec.bicycles.tech - Aug 11, 2002 by Bill - View Thread (43 articles)
Re: Recovering a seat ... of staple. - Trim the excess with scissors where you can, then with a
knife. It's a little tricky with Kevlar ! - Womens saddles ... rec.bicycles.tech - Jul 1, 1998 by
Andy Dingley - View Thread (7 articles)
Re: experienced with composite materials? ... Oh, and you'll need a good pair of scissors or knife
(professionals use ceramic scissors and knives) to cut anything with kevlar in - and they'll still
blunt ... rec.bicycles.tech - Sep 11, 1997 by Chris McSweeny - View Thread (3 articles)
Re: Anyone used Specialized Armadillo? ... The fibers were cut. Kevlar is tough but not
invulnerable. It can be cut with sharp scissors, and the edges on broken glass are EXTREMELY sharp.
... rec.bicycles.tech - Dec 28, 1996 by Ray Bowman - View Thread (18 articles)
Re: Hollow (cylindrical) spokes? ... I guess you have never played the ancient game of "Paper-Scissor-
Rock" If I can cut Kevlar with household scissors, it isn't as hard as steel and the ...
rec.bicycles.tech - Feb 4, 1995 by Jobst Brandt - View Thread (18 articles)
Re: strength of kevlar ... It has worked admirably. Kevlar can be cut with ordinary scissors more
easily than fiber glass. Could someone elaborate on this, with some numbers? .... ...
rec.bicycles.tech - Jan 30, 1995 by Composites Lab - View Thread (3 articles)
Re: Kevlar, Schmevlar ... Kevlar. For instance, ordinary steel scissors cut Kevlar cloth easily as
does glass even though it can stop bullets. Kevlar has ... rec.bicycles.tech - Jul 24, 1993 by Jobst
Brandt - View Thread (7 articles)
Possibly the Kevlar site is a little ambiguous? That is, I'm not sure when I re-read it whether they
mean that Kevlar is difficult to cut or drill at all (resistant) or difficult to cut or drill neatly
without fraying (messy).
"Finally, Kevlar is also very difficult to cut. You will need special scissors for cutting dry
fabric or prepreg, and special drill bits for drilling cured laminates. Cutting of cured laminates
without fraying is very difficult."
http://plastics.about.com/library/weekly/aa050597.htm
As for inspiring daughters with the story of the inventor of Kevlar, all I have is a pair of saucy
sisters, both of whom need constant stifling just to keep them (and their daughters) in their place.
Carl Fogel
D
Dianne_1234
Guest
On 27 Dec 2003 10:13:12 -0800, [email protected] (Carl Fogel)
wrote:
>Possibly the Kevlar site is a little ambiguous? That is, I'm not sure when I re-read it whether
>they mean that Kevlar is difficult to cut or drill at all (resistant) or difficult to cut or drill
>neatly without fraying (messy).
Ordinary industrial grade scissors (not grade-school scissors) in good shape will cut Kevlar ... for
a little while.
For a under a hundred bucks you can experience it yourself:
http://www.aircraftspruce.com/ntoc.php?sec=cm&cat=kevlar
http://www.aircraftspruce.com/catalog/cmpages/cutters.php
I once tried making skins for a disc wheel using Kevlar. I used industrial grade scissors (the
catalog said use for carbon fiber or fiberglass). I didn't spring for the ceramic scissors (the same
catalog said use for Kevlar) because my early trials showed it was easy to cut.
Well, after cutting out one circle the scissors were dull and it was painfully slow progress! I
bought and dulled several more industrial grade scissors before I knuckled under and shelled out for
the ceramic ones.
I never did finish the disc. Never did much more with Kevlar, either.
wrote:
>Possibly the Kevlar site is a little ambiguous? That is, I'm not sure when I re-read it whether
>they mean that Kevlar is difficult to cut or drill at all (resistant) or difficult to cut or drill
>neatly without fraying (messy).
Ordinary industrial grade scissors (not grade-school scissors) in good shape will cut Kevlar ... for
a little while.
For a under a hundred bucks you can experience it yourself:
http://www.aircraftspruce.com/ntoc.php?sec=cm&cat=kevlar
http://www.aircraftspruce.com/catalog/cmpages/cutters.php
I once tried making skins for a disc wheel using Kevlar. I used industrial grade scissors (the
catalog said use for carbon fiber or fiberglass). I didn't spring for the ceramic scissors (the same
catalog said use for Kevlar) because my early trials showed it was easy to cut.
Well, after cutting out one circle the scissors were dull and it was painfully slow progress! I
bought and dulled several more industrial grade scissors before I knuckled under and shelled out for
the ceramic ones.
I never did finish the disc. Never did much more with Kevlar, either.
C
Carl Fogel
Guest
dianne_1234 <[email protected]> wrote in message news:<[email protected]>...
> On 27 Dec 2003 10:13:12 -0800, [email protected] (Carl Fogel) wrote:
>
> >Possibly the Kevlar site is a little ambiguous? That is, I'm not sure when I re-read it whether
> >they mean that Kevlar is difficult to cut or drill at all (resistant) or difficult to cut or
> >drill neatly without fraying (messy).
>
> Ordinary industrial grade scissors (not grade-school scissors) in good shape will cut Kevlar ...
> for a little while.
>
> For a under a hundred bucks you can experience it yourself:
> http://www.aircraftspruce.com/ntoc.php?sec=cm&cat=kevlar
> http://www.aircraftspruce.com/catalog/cmpages/cutters.php
>
> I once tried making skins for a disc wheel using Kevlar. I used industrial grade scissors (the
> catalog said use for carbon fiber or fiberglass). I didn't spring for the ceramic scissors (the
> same catalog said use for Kevlar) because my early trials showed it was easy to cut.
>
> Well, after cutting out one circle the scissors were dull and it was painfully slow progress! I
> bought and dulled several more industrial grade scissors before I knuckled under and shelled out
> for the ceramic ones.
>
> I never did finish the disc. Never did much more with Kevlar, either.
Dear Dianne,
As usual, you nail things down nicely. So the stuff can be cut, but quickly dulls even good steel
blades suitable for cutting carbon fiber--the Muscle Fork site is therefore probably right in saying
that Kevlar helps resist cutting and I was wrong to be wary of their claim.
Sorry about your snipped disc (and this triple pun).
Thanks,
Carl Fogel
> On 27 Dec 2003 10:13:12 -0800, [email protected] (Carl Fogel) wrote:
>
> >Possibly the Kevlar site is a little ambiguous? That is, I'm not sure when I re-read it whether
> >they mean that Kevlar is difficult to cut or drill at all (resistant) or difficult to cut or
> >drill neatly without fraying (messy).
>
> Ordinary industrial grade scissors (not grade-school scissors) in good shape will cut Kevlar ...
> for a little while.
>
> For a under a hundred bucks you can experience it yourself:
> http://www.aircraftspruce.com/ntoc.php?sec=cm&cat=kevlar
> http://www.aircraftspruce.com/catalog/cmpages/cutters.php
>
> I once tried making skins for a disc wheel using Kevlar. I used industrial grade scissors (the
> catalog said use for carbon fiber or fiberglass). I didn't spring for the ceramic scissors (the
> same catalog said use for Kevlar) because my early trials showed it was easy to cut.
>
> Well, after cutting out one circle the scissors were dull and it was painfully slow progress! I
> bought and dulled several more industrial grade scissors before I knuckled under and shelled out
> for the ceramic ones.
>
> I never did finish the disc. Never did much more with Kevlar, either.
Dear Dianne,
As usual, you nail things down nicely. So the stuff can be cut, but quickly dulls even good steel
blades suitable for cutting carbon fiber--the Muscle Fork site is therefore probably right in saying
that Kevlar helps resist cutting and I was wrong to be wary of their claim.
Sorry about your snipped disc (and this triple pun).
Thanks,
Carl Fogel
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