How does Bowden cable work
 

Hi all

I need to extend the Bowden cable for my bath pop-up waste. I have got a replacement cable and now struggling to fit it. The old cable is terminated at each end with a brass fitting which allows the full cable in one side but only the core the other.

I had to cut the old sheath off the brass fitting and the bit inside came out buy twisting it with a pliers and pulling it out.

Now having fitted the new one, when I operate the waste the sheath pops out of the brass fitting so just ends up using the force to move the sheath into a bit of an arc. It would appear that the sheath needs to be attached to the brass fitting somehow. Both old and new sheaths are a fairly loose fitting in the brass fitting so glue may not be strong enough (if I could work out which to use). The inside of the brass fitting is smooth so threading it on doesn't seem to be the trick either.

Anyone have any idea how this is supposed to be attached ? Maybe I am missing something about how Bowden cables work and the sheath doesn't need to be attached.

Any help appreciated

Thanks

Lee.

How does Bowden cable work
 

In article ,
wrote:
Anyone have any idea how this is supposed to be attached ? Maybe I am
missing something about how Bowden cables work and the sheath doesn't
need to be attached.

If you look at high load situations where you need flexible cables - like
say a car gearchange - they generally use two so the load is taken by each
as a pull.

If you wish to have one which both pulls and pushes - for low load only -
it need a solid inner (so far less flexible) and the outer secured at both
ends. That can be with a clamp, or a crimped on ferrule secured to a
bracket by a circlip, etc.

--
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Dave Plowman London SW
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How does Bowden cable work
 

On Sat, 9 Jun 2018 03:42:35 -0700 (PDT), wrote:

snip

Anyone have any idea how this is supposed to be attached ?

Nope, sorry.

Maybe I am missing something about how Bowden cables work and the sheath doesn't need to be attached.

snip

Whilst not familiar with such a system for a waste plug I am familiar
with Bowden cables in a general sense and I would say they (the outer)
have to be 'anchored' with reference to the inner and the force acting
on them (with exceptions).

Like, if you had a Bowden cable going a short distance in a straight
line between two points it's possible that the inner cable could act
like a simple pushrod and so the outer could be considered
superfluous.

Of if you have something like a remote (mechanical) shutter release
for a camera where it's generally only used for compression and the
inner poling out the open end is 'free', but would still need to be
activated with regard to the outer (eg, if you just push the inner the
other would move as well, resulting in nothing at the output end).

Another exception would be if the outer tube was rigid, then it might
get away with only being retained at one place (being rigid means it's
then being effectively retained at all places).

So, if we are talking about a plunger that causes a basin plug to 'pop
up', I would imagine it could be covered by any of the examples above?

Cheers, T i m

How does Bowden cable work
 

On Sat, 09 Jun 2018 12:24:05 +0100, "Dave Plowman (News)"
wrote:

In article ,
wrote:
Anyone have any idea how this is supposed to be attached ? Maybe I am
missing something about how Bowden cables work and the sheath doesn't
need to be attached.

If you look at high load situations where you need flexible cables - like
say a car gearchange - they generally use two so the load is taken by each
as a pull.

I thought they generally had two for the two planes of movement, one
doing the push pull and the other the rotation (to duplicate the 'H'
gear selector gate)?

If you wish to have one which both pulls and pushes - for low load only -
it need a solid inner (so far less flexible) and the outer secured at both
ends. That can be with a clamp, or a crimped on ferrule secured to a
bracket by a circlip, etc.

Yup, because the gear change on my Messerschmitt KR200 is 'sequential'
it just has a push-pull cable with more rigid 'ends' where it connects
to the gear change lever or gear selector arm on the engine.

It actually travels in a open 'Z', from by your right knee, up the RHS
of the cockpit, across the back and out into the engine bay and onto
the engine.

I think the brand is 'Teleflex'.

http://www.tnorrismarine.co.uk/produ...-morse-cables/

Cheers, T i m

How does Bowden cable work
 

Thanks both. It works on a push and pull basis. Essentially when you turn the knob one way it pulls the inner cable which in turn pulls a lever at the plug end and the plug pops up (or down can't recall which way around). When you turn the knob in the opposite direction it pushes the lever at the plug end and the plug does the opposite.

I have both solid and stranded core to try once I get the mechanism working..

Sounds like I have to somehow secure the outer sheath to the brass fittings.. Any ideas?

How does Bowden cable work
 

On 09/06/2018 12:44, wrote:
Thanks both. It works on a push and pull basis. Essentially when you turn the knob one way it pulls the inner cable which in turn pulls a lever at the plug end and the plug pops up (or down can't recall which way around). When you turn the knob in the opposite direction it pushes the lever at the plug end and the plug does the opposite.

I have both solid and stranded core to try once I get the mechanism working.

Sounds like I have to somehow secure the outer sheath to the brass fittings. Any ideas?


I assume the sheath is plastic on a steel spiral?

The only certain way is to remove the plastic and solder, or crimp the
brass onto the sheath. Otherwise glue, possibly using epoxy. It needs to
cope with max push.

Since the cable is put in compression solid would be better.

How does Bowden cable work
 

Yes it is a steel spiral encased in plastic. The brass is thick (couple of mm) so no way to crimp it onto the sheath unfortunately.

How does Bowden cable work
 

On 09/06/2018 13:42, wrote:
Yes it is a steel spiral encased in plastic. The brass is thick (couple of mm) so no way to crimp it onto the sheath unfortunately.


I wish you would quote the text you're replying to. It is usenet convention.

Bowden cables are best where the sheath is in tension. They really don't
work well in compression.

If the steel spiral is genuinely steel, and not stainless steel, I would
solder. But only because I'm familiar with the process.

2mm is not enough depth to thread, so glue is the only other option.

Can you not get a genuine replacement?

How does Bowden cable work
 

Thanks Fredxx. I am using the Google groups forum site so not sure why it doesn't quite the text.

Based on your post, am I supposed to cut the sheath such that it is tight between the 2 end points? I cut it with some slack to give me some room in case I needed to move something slightly.

The brass on the fitting is around 2mm thick around the hole the sheath goes into. . The depth of the hole is around 6mm

How does Bowden cable work
 

Fredxx explained on 09/06/2018 :
Bowden cables are best where the sheath is in tension. They really don't work
well in compression.

Sheath in compression, inner in tension!

How does Bowden cable work
 

I can't put the sheath in compression as it runs from the trap of the bath up to the knob on top of the bath so needs to flex around contour of the bath.

How does Bowden cable work
 

How does Bowden cable work
 

On 09/06/18 15:28, Harry Bloomfield wrote:
presented the following explanation :
I can't put the sheath in compression as it runs from the trap of the
bath up to the knob on top of the bath so needs to flex around contour
of the bath.

Usually Bowden cables work with the inner being pulled (tension) against
the outer, which is compressed. Outers have limited ability to withstand
tension, because if too much tension is applied, then they easily stretch.


I don't think the outer compresses much. It is a spiral wrap so it is
flexible but, as it bends, the spiral turns are in contact. I doubt the
metal will compress much. The 'gap' between the turns on the outer of
the bend may close a bit as the device is operated- typically you see
the outer move a bit. As you say, the inner is under tension.

How does Bowden cable work
 

On 09/06/2018 15:11, Harry Bloomfield wrote:
Fredxx explained on 09/06/2018 :
Bowden cables are best where the sheath is in tension. They really
don't work well in compression.

Sheath in compression, inner in tension!

Apologies - spot on for noticing.

How does Bowden cable work
 

Brian Reay was thinking very hard :
I don't think the outer compresses much. It is a spiral wrap so it is
flexible but, as it bends, the spiral turns are in contact. I doubt the metal
will compress much. The 'gap' between the turns on the outer of the bend may
close a bit as the device is operated- typically you see the outer move a
bit. As you say, the inner is under tension.

I agree, the outer doesn't compress much, but they come under
compression when the lever or what ever is operated.

How does Bowden cable work
 

How does Bowden cable work
 

Bowden cables work due to the core piece having nowhere to go but up and
down the inside of the sheath. Its obvious that if the sheath is not
continuous then you will end up with just a cable that grows longer and
shorter by bulging.

Depending on the design normally the ends are mirror images of each other.
However as long as you can hold the two sheaths together you should be OK.
Can you not use a small clamp. The ends are normally solid, not the bendy
springy stuff the rest of the outer is made of. You need to make sure its
stronger than the combined force of the friction in the cable and the force
needed to raise and lower the plug. Back many years ago when TVs were dual
standard some very long bowden cables were used and the ends often clamped
to allow for switch movement adjustment.


Brian

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wrote in message
...
Hi all

I need to extend the Bowden cable for my bath pop-up waste. I have got a
replacement cable and now struggling to fit it. The old cable is terminated
at each end with a brass fitting which allows the full cable in one side but
only the core the other.

I had to cut the old sheath off the brass fitting and the bit inside came
out buy twisting it with a pliers and pulling it out.

Now having fitted the new one, when I operate the waste the sheath pops out
of the brass fitting so just ends up using the force to move the sheath into
a bit of an arc. It would appear that the sheath needs to be attached to the
brass fitting somehow. Both old and new sheaths are a fairly loose fitting
in the brass fitting so glue may not be strong enough (if I could work out
which to use). The inside of the brass fitting is smooth so threading it on
doesn't seem to be the trick either.

Anyone have any idea how this is supposed to be attached ? Maybe I am
missing something about how Bowden cables work and the sheath doesn't need
to be attached.

Any help appreciated

Thanks

Lee.

How does Bowden cable work
 

On 09/06/2018 12:24, Dave Plowman (News) wrote:
In article ,
wrote:
Anyone have any idea how this is supposed to be attached ? Maybe I am
missing something about how Bowden cables work and the sheath doesn't
need to be attached.

If you look at high load situations where you need flexible cables - like
say a car gearchange - they generally use two so the load is taken by each
as a pull.

If you wish to have one which both pulls and pushes - for low load only -
it need a solid inner (so far less flexible) and the outer secured at both
ends. That can be with a clamp, or a crimped on ferrule secured to a
bracket by a circlip, etc.

Agreed. The common instance of a push-pull cable, in the good old days,
was in car choke cables. IIRC bonnet releases also sometimes had (and
still have) a solid inner. But then they have a pretty fixed run and
don't need much flexibility.

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How does Bowden cable work
 

Looks like soldering the sheath into the fitting is the best next step. Do I use a normal blow torch and plumbers solder? Is also would the fit copper pipe?

How does Bowden cable work
 

Hi all

I have taken some photos and tried to upload them to a public album (hopefully not done this for ages). They show the fittings and particularly the brass fitting I need to connect the sheath to. Hopefully this works

https://photos.app.goo.gl/L44RinHPY2v2UeEbA

I have tried some searching but can only find examples of soldering the fitting to the wire rather than the sheath to the fitting. They seemed to use "silver solder" which I assume is not the same as plumbing solder

Thanks

Lee.

How does Bowden cable work
 

wrote:
Hi all

I have taken some photos and tried to upload them to a public album
(hopefully not done this for ages). They show the fittings and
particularly the brass fitting I need to connect the sheath to. Hopefully this works

https://photos.app.goo.gl/L44RinHPY2v2UeEbA

I have tried some searching but can only find examples of soldering the
fitting to the wire rather than the sheath to the fitting. They seemed
to use "silver solder" which I assume is not the same as plumbing solder

Thanks

Lee.


I think this would have been crimped to the sheath originally. I doubt
youll have much joy soldering. Id try epoxy resin or replace the whole
mech (control and pop-up) as I doubt it was designed to be replace
piecemeal.

Tim

--
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How does Bowden cable work
 

On 12/06/18 20:30, wrote:
Hi all

I have taken some photos and tried to upload them to a public album (hopefully not done this for ages). They show the fittings and particularly the brass fitting I need to connect the sheath to. Hopefully this works

https://photos.app.goo.gl/L44RinHPY2v2UeEbA

I have tried some searching but can only find examples of soldering the fitting to the wire rather than the sheath to the fitting. They seemed to use "silver solder" which I assume is not the same as plumbing solder

Thanks

Lee.

Bowden cables typically only work in tension so there is no need to fix
the outer to the ferrule

How does Bowden cable work
 

The brass of the fitting it too thick for it to be crimped and it is perfectly smooth with no sign of buckling. A few people here have said the sheath needs to be under tension. Given the Bowden cable forms an arch from the waste to the knob, how do I put it under tension? Pushing the ends of the sheath just alters the curve of the arc. I suspect I am missing something - sorry

How does Bowden cable work
 

wrote:
The brass of the fitting it too thick for it to be crimped and it is
perfectly smooth with no sign of buckling. A few people here have said
the sheath needs to be under tension. Given the Bowden cable forms an
arch from the waste to the knob, how do I put it under tension? Pushing
the ends of the sheath just alters the curve of the arc. I suspect I am
missing something - sorry


Its only under tension when you turn the knob to pop the plug up. Its not
pre-tensioned. The sheath just has to be securely anchored at each end.

Tim

--
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How does Bowden cable work
 

Tim+ wrote:
wrote:
The brass of the fitting it too thick for it to be crimped and it is
perfectly smooth with no sign of buckling. A few people here have said
the sheath needs to be under tension. Given the Bowden cable forms an
arch from the waste to the knob, how do I put it under tension? Pushing
the ends of the sheath just alters the curve of the arc. I suspect I am
missing something - sorry


Its only under tension when you turn the knob to pop the plug up. Its not
pre-tensioned. The sheath just has to be securely anchored at each end.

Tim


Which is why typically replacement mechs incorporate both ends (with no
need to cobble bits together).

https://www.ebay.co.uk/itm/Concealed...e/171874130165

Tim


--
Please don't feed the trolls

How does Bowden cable work
 

On Tue, 12 Jun 2018 12:30:52 -0700 (PDT), wrote:

Hi all

I have taken some photos and tried to upload them to a public album (hopefully not done this for ages). They show the fittings and particularly the brass fitting I need to connect the sheath to. Hopefully this works

https://photos.app.goo.gl/L44RinHPY2v2UeEbA

A picture speaks 1000 words. ;-)

I have tried some searching but can only find examples of soldering the fitting to the wire rather than the sheath to the fitting. They seemed to use "silver solder" which I assume is not the same as plumbing solder

If that fitting is plastic and that brass socket doesn't release from
the fitting I wouldn't want to solder it in place.

As I believe has been mentioned, it might be best (therefore) to
'glue' the Bowden outer to the socket using a 'Liquid Metal' epoxy.
The bond will be in shear and as long as it's all nice and clean and
dry when done, shouldn't ever come out again. ;-)

Cheers, T i m

How does Bowden cable work
 

Luckily the brass bit does come out it is secured using a clip the other side.

How does Bowden cable work
 

On Tue, 12 Jun 2018 23:32:31 -0700 (PDT), wrote:

Luckily the brass bit does come out it is secured using a clip the other side.

Whilst that is good, I'd still not bother trying to solder any of
those bits together because it will still probably melt the sheath off
the outer.

Clean the inside of the brass bit out with some coarse abrasive paper
/ round file / sharp small screwdriver (to remove and debris and
create a key) and clean both parts with a suitable solvent.

Mix up some suitable quantity of a quality epoxy, apply to both parts,
put together and leave 24 hours. Refit and just forever without that
part ever being a problem ever again?

Personally I think JB Weld would be ideal (if not overkill) but it's
not quite so easy to get in the UK as it was (but still on eBay etc).

Cheers, T i m

How does Bowden cable work
 

On 12/06/2018 20:30, wrote:
Hi all

I have taken some photos and tried to upload them to a public album (hopefully not done this for ages). They show the fittings and particularly the brass fitting I need to connect the sheath to. Hopefully this works

https://photos.app.goo.gl/L44RinHPY2v2UeEbA

I have tried some searching but can only find examples of soldering the fitting to the wire rather than the sheath to the fitting. They seemed to use "silver solder" which I assume is not the same as plumbing solder

Thanks

Lee.

Very helpful. "Silver soldering" is done at red heat, I think even "soft
soldering" (i.e. plumbing / electrical) will deform the plastic however
careful you are. I would go for epoxy: abrade and degrease the parts
first. Someone has already suggested this.

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How does Bowden cable work
 

On 13/06/2018 08:27, T i m wrote:
On Tue, 12 Jun 2018 23:32:31 -0700 (PDT), wrote:

Luckily the brass bit does come out it is secured using a clip the other side.

Whilst that is good, I'd still not bother trying to solder any of
those bits together because it will still probably melt the sheath off
the outer.

Clean the inside of the brass bit out with some coarse abrasive paper
/ round file / sharp small screwdriver (to remove and debris and
create a key) and clean both parts with a suitable solvent.

Mix up some suitable quantity of a quality epoxy, apply to both parts,
put together and leave 24 hours. Refit and just forever without that
part ever being a problem ever again?

Personally I think JB Weld would be ideal (if not overkill) but it's
not quite so easy to get in the UK as it was (but still on eBay etc).

Cheers, T i m

Spot on, I was going to say the same thing.

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How does Bowden cable work
 

On Wed, 13 Jun 2018 09:23:54 +0100, newshound
wrote:

SNIP

Mix up some suitable quantity of a quality epoxy, apply to both parts,
put together and leave 24 hours. Refit and just forever without that
part ever being a problem ever again?

Personally I think JB Weld would be ideal (if not overkill) but it's
not quite so easy to get in the UK as it was (but still on eBay etc).


Spot on, I was going to say the same thing.

I think if you have tried to do this sort of thing before (and I have,
many times) I think it's both the easiest and most-likely-to-succeed
option. ;-)

The key is the material to be glued. As long as it's all stuff that
you have had experience of before and know it to be good, then the
total outcome should be good. If one is (say) an unknown type of
plastic then I might try a test first and go from there.

The other thing is 'what are you trying to get the adhesive to do?' If
it's to provide material / support itself then 'it' has to be strong
enough to do so (like JB Weld). If you were retaining something that
might need to move a bit but wouldn't have a lot of strain on it then
something like silicone / Evo-Stick can be 'better' than something
more rigid.

In the OP's case I believe the goal is to rigidly bond the outer of a
'flexible link' to a bracket that uses a form or ferrule that was
previously attached somehow. Therefore, a rigid bond should be fine
and as both steel (coil outer) and brass are very compatible with JB
weld, I think as long as the surfaces are (chemically) clean and even
just enough applied to both surfaces to fill the void as completely as
possible, you would be hard pressed to get the two apart without
destroying both (that is my ultimate test). ;-)

Cheers, T i m

How does Bowden cable work
 

On 13/06/18 09:22, newshound wrote:
On 12/06/2018 20:30, wrote:
Hi all

I have taken some photos and tried to upload them to a public album
(hopefully not done this for ages). They show the fittings and
particularly the brass fitting I need to connect the sheath to.
Hopefully this works

https://photos.app.goo.gl/L44RinHPY2v2UeEbA

I have tried some searching but can only find examples of soldering
the fitting to the wire rather than the sheath to the fitting.Â* They
seemed to use "silver solder" which I assume is not the same as
plumbing solder

Thanks

Lee.

Very helpful. "Silver soldering" is done at red heat, I think even "soft
soldering" (i.e. plumbing / electrical) will deform the plastic however
careful you are. I would go for epoxy: abrade and degrease the parts
first. Someone has already suggested this.

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Silver soldreing is done at a bit less than red heat, but yes, its way
above 'soft solder'


--
"And if the blind lead the blind, both shall fall into the ditch".

Gospel of St. Mathew 15:14

How does Bowden cable work
 

On 13/06/2018 19:08, The Natural Philosopher wrote:
On 13/06/18 09:22, newshound wrote:
On 12/06/2018 20:30, wrote:
Hi all

I have taken some photos and tried to upload them to a public album
(hopefully not done this for ages). They show the fittings and
particularly the brass fitting I need to connect the sheath to.
Hopefully this works

https://photos.app.goo.gl/L44RinHPY2v2UeEbA

I have tried some searching but can only find examples of soldering
the fitting to the wire rather than the sheath to the fitting.Â* They
seemed to use "silver solder" which I assume is not the same as
plumbing solder

Thanks

Lee.

Very helpful. "Silver soldering" is done at red heat, I think even
"soft soldering" (i.e. plumbing / electrical) will deform the plastic
however careful you are. I would go for epoxy: abrade and degrease the
parts first. Someone has already suggested this.

---
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Silver soldreing is done at a bit less than red heat, but yes, its way
above 'soft solder'


Easy Flo No 2 is one of the lowest, 608 to 617 C, which is very dark
red. I reckon you need to get your work up to near enough 700 to be
practicable, which is dull red. Not bright, I agree, but clearly visible
in a dark-ish workshop.

How does Bowden cable work
 

In article ,
Tjoepstil wrote:
Bowden cables typically only work in tension so there is no need to fix
the outer to the ferrule

Do try and keep up.

--
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Dave Plowman London SW
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