Stuck Ferrule (female end) question

On Jul 4, 11:14*pm, BJConner wrote:
On Jul 4, 9:41*am, riverman wrote:



OK, imagine that you have a set of stuck ferrules, Your only tools
available are cold and hot water, specifically to pour over the
ferrules, as a pair, not to put on one side or the other. The
question: which will loosen the ferrules and why?

Some considerations: its pretty obvious that the male end will
contract in cold water (no jokes, please) so that part will definitely
loosen if given a cold water bath.

However, the female end is less clear. Think of a donut (as the female
end of a ferrule resembles a donut in cross-section): first instincts
may say to heat the female end to expand it, but when a donut expands,
the hole actually gets smaller. SO heating the female end may make the
ferrule tighter.

So what if we use cold water on the female end. If an entire donut
shrinks, the center hole gets smaller too. So cooling the female end
may make the ferrule tighter also. Hmm...

So which will cause the hole on the female end to become looser/
larger?

--riverman

Graphite has a low coefficient of thermal expansion. *If you have
jamed the rod together itmay not be possible to loosen it by
differentially heating them. *The male furrel may be expanded into
it's elastic range and heating won't expand it enough.
Brute force may be the only way, in which case the design of the grip
mechanism of both sections is critical.
OR you could drill a hole through the but of the rod into the but
section install a valve stem and pump it up.

Sorry.....

Disregard my response. It would work only for metal ferrules.

Didn't realize the rod was graphite.

cheers

oz

On 7/4/10 9:38 PM, george9219 wrote:
On Jul 4, 1:02 pm, wrote:
On 7/4/10 10:41 AM, riverman wrote:



However, the female end is less clear. Think of a donut (as the female
end of a ferrule resembles a donut in cross-section): first instincts
may say to heat the female end to expand it, but when a donut expands,
the hole actually gets smaller. SO heating the female end may make the
ferrule tighter.

I'm afraid that you're wrong. Heating the female ferrule will cause the
hole to expand. So it's best to heat the female ferrule and cool the
male ferrule.

--
Cut "to the chase" for my email address.

What RW said. Heat the female ferrule. The wall section of the female
has less mass and will expand faster than the male section.

The donut analogy is misleading. A cooking donut doesn't expand like a
"normal" material undergoing classic thermal expansion. A better analogy
is that the cross section of the ferrule would expand like a
photographic enlargement, in all directions, hole and all. That's why
mechanics sometimes use a torch to free a stuck nut. (I wouldn't use a
torch on a ferrule, but I'd use a XC ski waxing iron, carefully. You're
in Sweden, right?)

In any case, I wouldn't hold much hope for the thermal method of getting
the ferrules apart, although it's worth a try. Brute force is the
answer, I think, and if you aren't strong enough you need to find a way
to get mechanical advantage (or more hands to help).

BTW, riverman, is this a real problem you're facing or is it a quiz
question?

--
Cut "to the chase" for my email address.

On Jul 5, 12:01*pm, rw wrote:
On 7/4/10 9:38 PM, george9219 wrote:





On Jul 4, 1:02 pm, *wrote:
On 7/4/10 10:41 AM, riverman wrote:

However, the female end is less clear. Think of a donut (as the female
end of a ferrule resembles a donut in cross-section): first instincts
may say to heat the female end to expand it, but when a donut expands,
the hole actually gets smaller. SO heating the female end may make the
ferrule tighter.

I'm afraid that you're wrong. Heating the female ferrule will cause the
hole to expand. So it's best to heat the female ferrule and cool the
male ferrule.

--
Cut "to the chase" for my email address.

What RW said. Heat the female ferrule. The wall section of the female
has less mass and will expand faster than the male section.

The donut analogy is misleading. A cooking donut doesn't expand like a
"normal" material undergoing classic thermal expansion. A better analogy
is that the cross section of the ferrule would expand like a
photographic enlargement, in all directions, hole and all. That's why
mechanics sometimes use a torch to free a stuck nut. (I wouldn't use a
torch on a ferrule, but I'd use a XC ski waxing iron, carefully. You're
in Sweden, right?)

In any case, I wouldn't hold much hope for the thermal method of getting
the ferrules apart, although it's worth a try. Brute force is the
answer, I think, and if you aren't strong enough you need to find a way
to get mechanical advantage (or more hands to help).

BTW, riverman, is this a real problem you're facing or is it a quiz
question?

--
Cut "to the chase" for my email address.

It's mostly a quiz question, generated at the end of a string of
musings while casting. I dipped my travel rod in the icy water while
fishing, then noticed a short while later that the ferrule had
loosened, maybe (or maybe not) because of the immersion. So I jammed
the ferrules tightly together, however, when I tried to disassemble
the rod later, it was jammed. Although I was able to get the sections
apart using the 'behind the knee' method, I wondered about the role of
cold water immersion, and the effect on the seated ferrules and when
the rod warmed up. So I started thinking about what role hot or cold
water would have on each section.

The male section is easy....it should contract with cold water, even
if just a little. But the question began nagging me about the action
of the female section. Specifically, would cold water expand or
decrease the radius of the hole, and if it decreased it, would it
decrease less then the decrease of the male section (effectively
loosening the ferrules).

I'm not convinced that heat expands the radius of the hole, as in a
photographic enlargement. Objects expand around their physical mass.
There is a classic physics demonstration with a steel ring and a steel
ball where you heat the ring and find that the ball will not fit
through the ring. So, just as the hole in a rising donut (or bagel is
more like it) gets smaller, I would expect the hole to get smaller if
you heated the female section. But countereffecting that would be that
the circumference of the torus would also increase. Maybe there is
some sort of ratio of circumference to torus thickness where the hole
actually does not change....I don't know. But the action of the female
end of a ferrule is a very thought-provoking thing.

--riverman

On 7/5/10 5:12 AM, riverman wrote:

I'm not convinced that heat expands the radius of the hole, as in a
photographic enlargement. Objects expand around their physical mass.
There is a classic physics demonstration with a steel ring and a steel
ball where you heat the ring and find that the ball will not fit
through the ring. So, just as the hole in a rising donut (or bagel is
more like it) gets smaller, I would expect the hole to get smaller if
you heated the female section. But countereffecting that would be that
the circumference of the torus would also increase. Maybe there is
some sort of ratio of circumference to torus thickness where the hole
actually does not change....I don't know. But the action of the female
end of a ferrule is a very thought-provoking thing.

http://physics.bu.edu/~duffy/py105/Temperature.html

--
Cut "to the chase" for my email address.

On 7/5/10 7:08 AM, rw wrote:
On 7/5/10 5:12 AM, riverman wrote:

I'm not convinced that heat expands the radius of the hole, as in a
photographic enlargement. Objects expand around their physical mass.
There is a classic physics demonstration with a steel ring and a steel
ball where you heat the ring and find that the ball will not fit
through the ring. So, just as the hole in a rising donut (or bagel is
more like it) gets smaller, I would expect the hole to get smaller if
you heated the female section. But countereffecting that would be that
the circumference of the torus would also increase. Maybe there is
some sort of ratio of circumference to torus thickness where the hole
actually does not change....I don't know. But the action of the female
end of a ferrule is a very thought-provoking thing.

http://physics.bu.edu/~duffy/py105/Temperature.html


BTW, I think you're misremembering the ring and ball experiment. It
actually demonstrates just what I (and others) have been saying about
thermal expansion of a hole.

--
Cut "to the chase" for my email address.

On Jul 5, 4:12*am, riverman wrote:
On Jul 5, 12:01*pm, rw wrote:





On 7/4/10 9:38 PM, george9219 wrote:

On Jul 4, 1:02 pm, *wrote:
On 7/4/10 10:41 AM, riverman wrote:

However, the female end is less clear. Think of a donut (as the female
end of a ferrule resembles a donut in cross-section): first instincts
may say to heat the female end to expand it, but when a donut expands,
the hole actually gets smaller. SO heating the female end may make the
ferrule tighter.

I'm afraid that you're wrong. Heating the female ferrule will cause the
hole to expand. So it's best to heat the female ferrule and cool the
male ferrule.

--
Cut "to the chase" for my email address.

What RW said. Heat the female ferrule. The wall section of the female
has less mass and will expand faster than the male section.

The donut analogy is misleading. A cooking donut doesn't expand like a
"normal" material undergoing classic thermal expansion. A better analogy
is that the cross section of the ferrule would expand like a
photographic enlargement, in all directions, hole and all. That's why
mechanics sometimes use a torch to free a stuck nut. (I wouldn't use a
torch on a ferrule, but I'd use a XC ski waxing iron, carefully. You're
in Sweden, right?)

In any case, I wouldn't hold much hope for the thermal method of getting
the ferrules apart, although it's worth a try. Brute force is the
answer, I think, and if you aren't strong enough you need to find a way
to get mechanical advantage (or more hands to help).

BTW, riverman, is this a real problem you're facing or is it a quiz
question?

--
Cut "to the chase" for my email address.

It's mostly a quiz question, generated at the end of a string of
musings while casting. I dipped my travel rod in the icy water while
fishing, then noticed a short while later that the ferrule had
loosened, maybe (or maybe not) because of the immersion. So I jammed
the ferrules tightly together, however, when I tried to disassemble
the rod later, it was jammed. Although I was able to get the sections
apart using the 'behind the knee' method, I wondered about the role of
cold water immersion, and the effect on the seated ferrules and when
the rod warmed up. So I started thinking about what role hot or cold
water would have on each section.

The male section is easy....it should contract with cold water, even
if just a little. But the question began nagging me about the action
of the female section. Specifically, would cold water expand or
decrease the radius of the hole, and if it decreased it, would it
decrease less then the decrease of the male section (effectively
loosening the ferrules).

I'm not convinced that heat expands the radius of the hole, as in a
photographic enlargement. Objects expand around their physical mass.
There is a classic physics demonstration with a steel ring and a steel
ball where you heat the ring and find that the ball will not fit
through the ring. So, just as the hole in a rising donut (or bagel is
more like it) gets smaller, I would expect the hole to get smaller if
you heated the female section. But countereffecting that would be that
the circumference of the torus would also increase. Maybe there is
some sort of ratio of circumference to torus thickness where the hole
actually does not change....I don't know. But the action of the female
end of a ferrule is a very thought-provoking thing.

--riverman- Hide quoted text -

- Show quoted text -

Things do exapand like a photographic enlargement. Been there done
than and measured it.
One thing we have not considered is that the male and female ferrules
are made of different material. Rod blanks are made in one piece and
then cut into sections. Male ferrules are part of the blank and
female furrules are laid up on the exterior of the blank. The two
materials while they are the "same" could have different coefficients
of thermal expansion. The expoxy, resins and fiber used to make the
female ferrule could be different than those used to make the blank.
That could explain what you experienced in very cold water.

On 7/5/10 8:13 AM, BJConner wrote:

One thing we have not considered is that the male and female ferrules
are made of different material. Rod blanks are made in one piece and
then cut into sections. Male ferrules are part of the blank and
female furrules are laid up on the exterior of the blank. The two
materials while they are the "same" could have different coefficients
of thermal expansion. The expoxy, resins and fiber used to make the
female ferrule could be different than those used to make the blank.
That could explain what you experienced in very cold water.

That's a good point. In that scenario, the female ferrule would have a
larger coefficient of expansion than the male ferrule (it would shrink
faster when cooled). Which is a good design, if you think about it. In
the opposite case the rod would tend to come apart whenever it got cold.

--
Cut "to the chase" for my email address.

On Jul 5, 7:12*am, riverman wrote:
On Jul 5, 12:01*pm, rw wrote:



On 7/4/10 9:38 PM, george9219 wrote:

On Jul 4, 1:02 pm, *wrote:
On 7/4/10 10:41 AM, riverman wrote:

However, the female end is less clear. Think of a donut (as the female
end of a ferrule resembles a donut in cross-section): first instincts
may say to heat the female end to expand it, but when a donut expands,
the hole actually gets smaller. SO heating the female end may make the
ferrule tighter.

I'm afraid that you're wrong. Heating the female ferrule will cause the
hole to expand. So it's best to heat the female ferrule and cool the
male ferrule.

--
Cut "to the chase" for my email address.

What RW said. Heat the female ferrule. The wall section of the female
has less mass and will expand faster than the male section.

The donut analogy is misleading. A cooking donut doesn't expand like a
"normal" material undergoing classic thermal expansion. A better analogy
is that the cross section of the ferrule would expand like a
photographic enlargement, in all directions, hole and all. That's why
mechanics sometimes use a torch to free a stuck nut. (I wouldn't use a
torch on a ferrule, but I'd use a XC ski waxing iron, carefully. You're
in Sweden, right?)

In any case, I wouldn't hold much hope for the thermal method of getting
the ferrules apart, although it's worth a try. Brute force is the
answer, I think, and if you aren't strong enough you need to find a way
to get mechanical advantage (or more hands to help).

BTW, riverman, is this a real problem you're facing or is it a quiz
question?

--
Cut "to the chase" for my email address.

It's mostly a quiz question, generated at the end of a string of
musings while casting. I dipped my travel rod in the icy water while
fishing, then noticed a short while later that the ferrule had
loosened, maybe (or maybe not) because of the immersion. So I jammed
the ferrules tightly together, however, when I tried to disassemble
the rod later, it was jammed. Although I was able to get the sections
apart using the 'behind the knee' method, I wondered about the role of
cold water immersion, and the effect on the seated ferrules and when
the rod warmed up. So I started thinking about what role hot or cold
water would have on each section.

The male section is easy....it should contract with cold water, even
if just a little. But the question began nagging me about the action
of the female section. Specifically, would cold water expand or
decrease the radius of the hole, and if it decreased it, would it
decrease less then the decrease of the male section (effectively
loosening the ferrules).

I'm not convinced that heat expands the radius of the hole, as in a
photographic enlargement. Objects expand around their physical mass.
There is a classic physics demonstration with a steel ring and a steel
ball where you heat the ring and find that the ball will not fit
through the ring. So, just as the hole in a rising donut (or bagel is
more like it) gets smaller, I would expect the hole to get smaller if
you heated the female section. But countereffecting that would be that
the circumference of the torus would also increase. Maybe there is
some sort of ratio of circumference to torus thickness where the hole
actually does not change....I don't know. But the action of the female
end of a ferrule is a very thought-provoking thing.

--riverman

The hole expands. I hope you're not a physics teacher;-) Many years
ago, I was involved in the production of M-14 rifles. In order to
prevent corrosion and limit wear, a Stellite liner was permanently
inserted at the breech end of the barrel. The OD of the liner was an
interference fit (about .0002" larger, IIRC) with the ID of the
barrel. To accomplish the assembly, the liners were kept in a bucket
of dry ice, while the barrel was held in a fixture with an induction
coil surrounding the breech end. There were witness marks on the
barrel and liner, so the rifling would line up after assembly. The
induction coil would be turned on for a short period of time, (I don't
remember exactly how long), the liner would be picked up with tongs,
inserted into the barrel, and turned to line up the witness marks.
When the induction coil was turned off, there would be a audible
"click" as the ID of the barrel shrunk. The liners never moved after
that, even when the rifle was fired repeatedly on rapid fire.

On Jul 5, 3:27*pm, rw wrote:
On 7/5/10 7:08 AM, rw wrote:





On 7/5/10 5:12 AM, riverman wrote:

I'm not convinced that heat expands the radius of the hole, as in a
photographic enlargement. Objects expand around their physical mass.
There is a classic physics demonstration with a steel ring and a steel
ball where you heat the ring and find that the ball will not fit
through the ring. So, just as the hole in a rising donut (or bagel is
more like it) gets smaller, I would expect the hole to get smaller if
you heated the female section. But countereffecting that would be that
the circumference of the torus would also increase. Maybe there is
some sort of ratio of circumference to torus thickness where the hole
actually does not change....I don't know. But the action of the female
end of a ferrule is a very thought-provoking thing.

http://physics.bu.edu/~duffy/py105/Temperature.html

BTW, I think you're misremembering the ring and ball experiment. It
actually demonstrates just what I (and others) have been saying about
thermal expansion of a hole.

--
Cut "to the chase" for my email address.

You're right. I just saw this on youTube http://www.youtube.com/watch?v=V0ETKRz2UCA

So OK, the hole gets bigger when the female end is heated, however
the male end gets bigger also. Which gets bigger faster? If the male
end does, then that would tighten the ferrule. And would it make any
difference if the male end was solid vs a hollow tube?

--riverman

On Jul 5, 4:13*pm, BJConner wrote:
On Jul 5, 4:12*am, riverman wrote:





On Jul 5, 12:01*pm, rw wrote:

On 7/4/10 9:38 PM, george9219 wrote:

On Jul 4, 1:02 pm, *wrote:
On 7/4/10 10:41 AM, riverman wrote:

However, the female end is less clear. Think of a donut (as the female
end of a ferrule resembles a donut in cross-section): first instincts
may say to heat the female end to expand it, but when a donut expands,
the hole actually gets smaller. SO heating the female end may make the
ferrule tighter.

I'm afraid that you're wrong. Heating the female ferrule will cause the
hole to expand. So it's best to heat the female ferrule and cool the
male ferrule.

--
Cut "to the chase" for my email address.

What RW said. Heat the female ferrule. The wall section of the female
has less mass and will expand faster than the male section.

The donut analogy is misleading. A cooking donut doesn't expand like a
"normal" material undergoing classic thermal expansion. A better analogy
is that the cross section of the ferrule would expand like a
photographic enlargement, in all directions, hole and all. That's why
mechanics sometimes use a torch to free a stuck nut. (I wouldn't use a
torch on a ferrule, but I'd use a XC ski waxing iron, carefully. You're
in Sweden, right?)

In any case, I wouldn't hold much hope for the thermal method of getting
the ferrules apart, although it's worth a try. Brute force is the
answer, I think, and if you aren't strong enough you need to find a way
to get mechanical advantage (or more hands to help).

BTW, riverman, is this a real problem you're facing or is it a quiz
question?

--
Cut "to the chase" for my email address.

It's mostly a quiz question, generated at the end of a string of
musings while casting. I dipped my travel rod in the icy water while
fishing, then noticed a short while later that the ferrule had
loosened, maybe (or maybe not) because of the immersion. So I jammed
the ferrules tightly together, however, when I tried to disassemble
the rod later, it was jammed. Although I was able to get the sections
apart using the 'behind the knee' method, I wondered about the role of
cold water immersion, and the effect on the seated ferrules and when
the rod warmed up. So I started thinking about what role hot or cold
water would have on each section.

The male section is easy....it should contract with cold water, even
if just a little. But the question began nagging me about the action
of the female section. Specifically, would cold water expand or
decrease the radius of the hole, and if it decreased it, would it
decrease less then the decrease of the male section (effectively
loosening the ferrules).

I'm not convinced that heat expands the radius of the hole, as in a
photographic enlargement. Objects expand around their physical mass.
There is a classic physics demonstration with a steel ring and a steel
ball where you heat the ring and find that the ball will not fit
through the ring. So, just as the hole in a rising donut (or bagel is
more like it) gets smaller, I would expect the hole to get smaller if
you heated the female section. But countereffecting that would be that
the circumference of the torus would also increase. Maybe there is
some sort of ratio of circumference to torus thickness where the hole
actually does not change....I don't know. But the action of the female
end of a ferrule is a very thought-provoking thing.

--riverman- Hide quoted text -

- Show quoted text -

Things do exapand like a photographic enlargement. Been there done
than and measured it.
One thing we have not considered is that the male and female ferrules
are made of different material. Rod blanks *are made in one piece and
then cut into sections. *Male ferrules are part of the blank and
female furrules are laid up on the exterior of the blank. *The two
materials while they are the "same" could have different coefficients
of thermal expansion. *The expoxy, resins and fiber used to make the
female ferrule could be different than those used to make the blank.
That could explain what you experienced in very cold water.

In this case they are the same material. The ferrules are the actual
blank, no metal fittings on them.