OT: How can I glue a broken nylon gear?

J

Joerg

Guest
Hello Folks,

We were given a coocoo clock. I fixed it but must say that I was not
enthused about the quality of its innards. Long story short it all works
now except for the music and the dancing figurines. A nylon gear is
broken length-wise on one side. Sure enough this is the little gear
right before the air brake, meaning the one with the highest wear.
Wonder why that is nylon while the others are brass ...

Any ideas which adhesive would work here? Ideally something I can get in
the store. Google hasn't helped me on this one, there were only hints on
how to fix tent nylon and stuff like that. Reason I ask is that I have
exactly one chance to fix it with adhesive.

Regards, Joerg

http://www.analogconsultants.com
 
Joerg wrote:
Hello Folks,

We were given a coocoo clock. I fixed it but must say that I was not
enthused about the quality of its innards. Long story short it all works
now except for the music and the dancing figurines. A nylon gear is
broken length-wise on one side. Sure enough this is the little gear
right before the air brake, meaning the one with the highest wear.
Wonder why that is nylon while the others are brass ...

Any ideas which adhesive would work here? Ideally something I can get in
the store. Google hasn't helped me on this one, there were only hints on
how to fix tent nylon and stuff like that. Reason I ask is that I have
exactly one chance to fix it with adhesive.

Regards, Joerg

http://www.analogconsultants.com
Click to expand...
Your only hope may be superglue. Even better if you first clean it
using something they called 'cyanoprep'.

--
Luhan Monat: luhanis(at)yahoo(dot)com
http://members.cox.net/berniekm
"Any sufficiently advanced magick is
indistinguishable from technology."
 
Hello Luhan,

Your only hope may be superglue. Even better if you first clean it
using something they called 'cyanoprep'.
Click to expand...
That's what I was afraid it would be. I have seen superglue "eat"
portions of a similar part before.

Regards, Joerg

http://www.analogconsultants.com
 
"Joerg" <notthisjoergsch@removethispacbell.net> schreef in bericht
news:6A4ne.23259$J12.446@newssvr14.news.prodigy.com...
Hello Folks,

We were given a coocoo clock. I fixed it but must say that I was not
enthused about the quality of its innards. Long story short it all works
now except for the music and the dancing figurines. A nylon gear is
broken length-wise on one side. Sure enough this is the little gear
right before the air brake, meaning the one with the highest wear.
Wonder why that is nylon while the others are brass ...

Any ideas which adhesive would work here? Ideally something I can get in
the store. Google hasn't helped me on this one, there were only hints on
how to fix tent nylon and stuff like that. Reason I ask is that I have
exactly one chance to fix it with adhesive.
Click to expand...
Perhaps drill small holes on both sides of the crack, and 'sew'
it together with thin steel wire. Then cover the needlework with
Bison kit(tm). Or any other glue based on cyclohexaan, methylethylketon,
nafta, n-hexaan and ethylacetaat <g>.

--
Thanks, Frank.
(remove 'q' and 'invalid' when replying by email)
 
Hello Frank,

Perhaps drill small holes on both sides of the crack, and 'sew'
it together with thin steel wire. Then cover the needlework with
Bison kit(tm). Or any other glue based on cyclohexaan, methylethylketon,
nafta, n-hexaan and ethylacetaat <g>.
Click to expand...
That's a great method and I would have done it. But this gear is only
5mm in diameter and 3mm long.

Regards, Joerg

http://www.analogconsultants.com
 
On Tue, 31 May 2005 22:05:49 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hello Frank,

Perhaps drill small holes on both sides of the crack, and 'sew'
it together with thin steel wire. Then cover the needlework with
Bison kit(tm). Or any other glue based on cyclohexaan, methylethylketon,
nafta, n-hexaan and ethylacetaat <g>.

That's a great method and I would have done it. But this gear is only
5mm in diameter and 3mm long.

Regards, Joerg

http://www.analogconsultants.com
Click to expand...
Have you considered casting your own gear?

I don't think you can glue nylon.

I've not made gears, but I've duplicated less complex parts by using
casting latex to make a mold.

For instance, make a "sacrificial" mold, fill it with epoxy, then rip
away the mold.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
"Joerg" <notthisjoergsch@removethispacbell.net> schreef in bericht
news:1d5ne.713$IE7.284@newssvr21.news.prodigy.com...
Hello Frank,

Perhaps drill small holes on both sides of the crack, and 'sew'
it together with thin steel wire. Then cover the needlework with
Bison kit(tm). Or any other glue based on cyclohexaan, methylethylketon,
nafta, n-hexaan and ethylacetaat <g>.

That's a great method and I would have done it. But this gear is only
5mm in diameter and 3mm long.
Click to expand...
Ai, that's a small one. It is/was probably a press-fit gear, driving
a shaft rather than a free rotating intermediate gear. Once you remove
the shaft, the gap is probably closed. The pressure on such gears is
insane, glue won't hold that. You have to make a new one, not impossible
if you have a jewelers lathe and mill.

--
Thanks, Frank.
(remove 'q' and 'invalid' when replying by email)
 
Hello Jim,

Have you considered casting your own gear?
Click to expand...
That's a good idea. This whole thing came up when our former neighbors
visited last week. The husband said he could probably make a new gear
from brass. I just wanted to see whether there is an easier solution and
I could spare him the trouble. Plus they live across the ocean.

I don't think you can glue nylon.
Click to expand...
My gut feeling told me that, too. But engineering minds don't give up
until they know for sure...

Regards, Joerg

http://www.analogconsultants.com
 
Hello Frank,

... You have to make a new one, not impossible
if you have a jewelers lathe and mill.
Click to expand...
Been dreaming about having that for years. Maybe one day, when I retire.
If our generation can ever retire, that is.

I think you are right about the shaft. It may have been a press fit gear
before it broke.

Regards, Joerg

http://www.analogconsultants.com
 
On Tue, 31 May 2005 21:22:10 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hello Folks,

We were given a coocoo clock. I fixed it but must say that I was not
enthused about the quality of its innards. Long story short it all works
now except for the music and the dancing figurines. A nylon gear is
broken length-wise on one side. Sure enough this is the little gear
right before the air brake, meaning the one with the highest wear.
Wonder why that is nylon while the others are brass ...

Any ideas which adhesive would work here? Ideally something I can get in
the store. Google hasn't helped me on this one, there were only hints on
how to fix tent nylon and stuff like that. Reason I ask is that I have
exactly one chance to fix it with adhesive.
Click to expand...
---
I've never found anything that worked really well on Nylon, but these
folks might have something...

http://froogle.google.com/froogle?q=Nylon+glue&hl=en&lr=&sa=N&tab=ff&oi=froogler
--
John Fields
Professional Circuit Designer
 
Joerg wrote:
Hello Frank,

Perhaps drill small holes on both sides of the crack, and 'sew'
it together with thin steel wire. Then cover the needlework with
Bison kit(tm). Or any other glue based on cyclohexaan, methylethylketon,
nafta, n-hexaan and ethylacetaat <g>.


That's a great method and I would have done it. But this gear is only
5mm in diameter and 3mm long.
Click to expand...
Have you tried to see if you can find another one that fits? sound like
something that could be found in a model RC car or RC servo

-Lasse
 
Hello Lasse,

Have you tried to see if you can find another one that fits? sound like
something that could be found in a model RC car or RC servo
Click to expand...
That is another option but the gear is longer than most RC stuff. I
haven't seen a US supplier but in Europe there is a company called
"Selva" that supplies spare parts to watch makers. However, if you order
just one part and have it shipped to the US that gets expensive.

Regards, Joerg

http://www.analogconsultants.com
 
Hello John,

I've never found anything that worked really well on Nylon, but these
folks might have something...

http://froogle.google.com/froogle?q=Nylon+glue&hl=en&lr=&sa=N&tab=ff&oi=froogler
Click to expand...
Thanks! That is an interesting supplier. They say that their Pacer nylon
hinge glue will micro-etch. Maybe that and a somewhat loosened press-fit
of the gear does the trick. All this gear does is drive the air brake to
provide a somewhat regulated speed.

Regards, Joerg

http://www.analogconsultants.com
 
On Tue, 31 May 2005 22:32:33 +0000, Joerg wrote:

Hello Jim,

Have you considered casting your own gear?

That's a good idea. This whole thing came up when our former neighbors
visited last week. The husband said he could probably make a new gear
from brass. I just wanted to see whether there is an easier solution and
I could spare him the trouble. Plus they live across the ocean.

I don't think you can glue nylon.

My gut feeling told me that, too. But engineering minds don't give up
until they know for sure...
Click to expand...
To be honest, I'm kind of hoping that you'll cast a gear and take
pictures of the whole process. :)

I was going to suggest getting ahold of a piece of nylon and _carve_
one, but giving it a little thought, that's kind of a silly idea. :)

Good Luck!
Rich
 
Hello Rich,

To be honest, I'm kind of hoping that you'll cast a gear and take
pictures of the whole process. :)
Click to expand...
Along with my wife's face when she sees the resulting mess in the garage.

I was going to suggest getting ahold of a piece of nylon and _carve_
one, but giving it a little thought, that's kind of a silly idea. :)
Click to expand...
Actually I have "cut" a larger and slower running gear using a scroll
saw. If the saw still has decent bearings it can be done. Just not with
such small gears.

Regards, Joerg

http://www.analogconsultants.com
 
On Tue, 31 May 2005 15:18:07 -0700, Jim Thompson
<thegreatone@example.com> wrote:

On Tue, 31 May 2005 22:05:49 GMT, Joerg
notthisjoergsch@removethispacbell.net> wrote:

Hello Frank,

Perhaps drill small holes on both sides of the crack, and 'sew'
it together with thin steel wire. Then cover the needlework with
Bison kit(tm). Or any other glue based on cyclohexaan, methylethylketon,
nafta, n-hexaan and ethylacetaat <g>.

That's a great method and I would have done it. But this gear is only
5mm in diameter and 3mm long.

Regards, Joerg

http://www.analogconsultants.com

Have you considered casting your own gear?

I don't think you can glue nylon.

I've not made gears, but I've duplicated less complex parts by using
casting latex to make a mold.

For instance, make a "sacrificial" mold, fill it with epoxy, then rip
away the mold.
Click to expand...
Silicone sealant might work for the mold material. Fill the
center of the gear with the sealant, then put the gear down into
a thimble sized container of sealant. Might have to carefully
work the gear out with a straight pin or something similar to not
destroy the mold. Fill the mold with epoxy like JBweld. Keeping
the shaft hole in the center aligned might be a challange. Small
work, but low cost.
 
On Tue, 31 May 2005 21:22:10 GMT, the renowned Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hello Folks,

We were given a coocoo clock. I fixed it but must say that I was not
enthused about the quality of its innards. Long story short it all works
now except for the music and the dancing figurines. A nylon gear is
broken length-wise on one side. Sure enough this is the little gear
right before the air brake, meaning the one with the highest wear.
Wonder why that is nylon while the others are brass ...

Any ideas which adhesive would work here? Ideally something I can get in
the store. Google hasn't helped me on this one, there were only hints on
how to fix tent nylon and stuff like that. Reason I ask is that I have
exactly one chance to fix it with adhesive.
Click to expand...
I tried to fix an injection-molded nylon gear years ago that was part
of a VCR drive mechanism (to give you an idea of how long ago it was,
I paid $1,800 for the VCR, when a grilled-cheese sandwich and fries
was $1.25**) but with little luck. The main problem was that it broke
at the D-shaft (the drive) where all the force was.

My suggestion is to forget about trying to fix the gear, and
concentrate on finding a replacement. Comb all the local surplus shops
for little mechanisms like tape counters etc. that might have
(presumably metric) gears like that. You can make some measurements
and figure out the pitch or metric module (0.5mm maybe) of the gear
and the number of teeth (you can drill out or sleeve the shaft most
likely).


** I paid more like C$10.00 including tax & tip for a grilled cheese
sandwich and fries recently, but admittedly it was made with blue
cheese and peameal ("Canadian") bacon. ;-)


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
Hello Spehro,

I tried to fix an injection-molded nylon gear years ago that was part
of a VCR drive mechanism (to give you an idea of how long ago it was,
I paid $1,800 for the VCR, when a grilled-cheese sandwich and fries
was $1.25**) but with little luck.
Click to expand...
All I had in those days was a tube radio. But it was all I needed
because it had shortwave. The video recorder we had in school was like a
tape recorder. You had to make the spool at the far end catch the tape.

You guys in Canada will slowly kill yourselves with all that melted
cheese stuff, poutine and so on. Ever checked cholesterol levels ...?

...The main problem was that it broke
at the D-shaft (the drive) where all the force was.
Click to expand...
I believe mine would break just where it did before, or develop a
similar crack elsewhere.

My suggestion is to forget about trying to fix the gear, and
concentrate on finding a replacement. ...
Click to expand...
Yes, I think that message is sinking in. Maybe I do ask my friend to
make one, or do the sacrificial mold thing.

Regards, Joerg

http://www.analogconsultants.com
 
On Wed, 01 Jun 2005 02:12:27 GMT, the renowned Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hello Spehro,

I tried to fix an injection-molded nylon gear years ago that was part
of a VCR drive mechanism (to give you an idea of how long ago it was,
I paid $1,800 for the VCR, when a grilled-cheese sandwich and fries
was $1.25**) but with little luck.

All I had in those days was a tube radio. But it was all I needed
because it had shortwave. The video recorder we had in school was like a
tape recorder. You had to make the spool at the far end catch the tape.
Click to expand...
When I was in high school they bought a portable B&W video recorder
that was about the size of a carry-on bag, with a shoulder strap. It
cost about the price of a cheap car at the time. As a Film and TV Arts
student, I was allowed to take it home and play with it. The schools
had a ton of money back then. Unlimited 8mm film and processing.
Beatiful fully equipped auto, wood, electrical and machine shops
including EDM machines. You can imagine what kind of mischief a boy
that age could get into with a novel device such as a portable VCR.
;-)

You guys in Canada will slowly kill yourselves with all that melted
cheese stuff, poutine and so on. Ever checked cholesterol levels ...?
Click to expand...
Mine's okay. ;-) In moderation, that sort of stuff's not so bad.
McDonalds, potato chips and donuts are probably a lot worse for you.

...The main problem was that it broke
at the D-shaft (the drive) where all the force was.

I believe mine would break just where it did before, or develop a
similar crack elsewhere.

My suggestion is to forget about trying to fix the gear, and
concentrate on finding a replacement. ...

Yes, I think that message is sinking in. Maybe I do ask my friend to
make one, or do the sacrificial mold thing.

Regards, Joerg

http://www.analogconsultants.com
Click to expand...

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
Joerg wrote:
Have you considered casting your own gear?

That's a good idea.
Click to expand...
I agree you won't have any luck gluing a nylon part.

Try http://www.smooth-on.com for casting materials - they've manufacture
a huge selection.

Interesting tutorials, cheap starter kits, etc. If you're in for the
experience, you could get everything you need to make a medium-scale
mess for $50. :)

Supposedly the latex molds will even duplicate finger prints if you
don't clean the master part well, so duplicting the detail shouldn't be
a problem. The hard part will probably be the press-fit shaft hole,
though perhaps it can be epoxied onto the shaft.

Richard
 
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