I'm hoping that the metalworking community can help me out. I no
nothing about this subject but would like some advice.

I broke the speaker binding post on a very expensive and very heavy
subwoofer (A Wilsong Audio Puppy) The post is about 3-4mm diameter. I
can't remove the piece that is still embedded in the speaker because it
is soldered in and the circuitry is inaccessably potted. To ship to the
manufacturer and have them fix would be very expensive.

I'm thinking that my solution may be to drill a core and tap both ends
of the broken pin and connect them with a (conductive) headless bolt.

Would my local machine shop be able to do this and how much should I
expect to pay? I'm on the San Francisco peninsula.

I still get electrical contact when I insert the pin but I'm not happy
with this solution.

Any help would be greatly appreciated. email replies greatly
appreciated.

So there's a stub sticking out? I'd make a brass sleeve that just fit over it
and get a matching threaded piece and put it in the other end of the brass
sleeve and crimp it on. You can get small brass tubing short pieces from hobby
shops, and you can likely cut it yourself if you have a Dremel tool (with one of
those superthin abrasive wheels) or maybe the hobby store guy would take pity on
you and cut it. A better fix would be to solder the sleeve, but then you run the
risk of the heat doing something bad at the other end of the stub.

If you don't have a stub sticking out, what do you have?

GWE

wrote:

I'm hoping that the metalworking community can help me out. I no
nothing about this subject but would like some advice.

I broke the speaker binding post on a very expensive and very heavy
subwoofer (A Wilsong Audio Puppy) The post is about 3-4mm diameter. I
can't remove the piece that is still embedded in the speaker because it
is soldered in and the circuitry is inaccessably potted. To ship to the
manufacturer and have them fix would be very expensive.

I'm thinking that my solution may be to drill a core and tap both ends
of the broken pin and connect them with a (conductive) headless bolt.

Would my local machine shop be able to do this and how much should I
expect to pay? I'm on the San Francisco peninsula.

I still get electrical contact when I insert the pin but I'm not happy
with this solution.

Any help would be greatly appreciated. email replies greatly
appreciated.

wrote:

I broke the speaker binding post on a very expensive and very heavy

There are also conductive glues that might help. Expensive, but they do
the job.
Depends on how things are. A photo would help.


Nick
--
Motormodelle / Engine Models:
http://www.motor-manufaktur.de
Ellwe 2FB * VTM 87 * DLM-S3a * cubic
more to come ...

Check around for a speaker repair place. I have a local "hole in the
wall" place that does good work at very reasonable prices.

wrote:
I'm hoping that the metalworking community can help me out. I no
nothing about this subject but would like some advice.

I broke the speaker binding post on a very expensive and very heavy
subwoofer (A Wilsong Audio Puppy) The post is about 3-4mm diameter. I
can't remove the piece that is still embedded in the speaker because it
is soldered in and the circuitry is inaccessably potted. To ship to the
manufacturer and have them fix would be very expensive.

I'm thinking that my solution may be to drill a core and tap both ends
of the broken pin and connect them with a (conductive) headless bolt.

Would my local machine shop be able to do this and how much should I
expect to pay? I'm on the San Francisco peninsula.

I still get electrical contact when I insert the pin but I'm not happy
with this solution.

Any help would be greatly appreciated. email replies greatly
appreciated.

I wish I had a stub sticking out.

The post broke off about 1/2 cm inside the speaker. I have the broken
off piece and a hole with the other half inside. There is no way to
extract the other piece since it is soldered in and the circuitry is
potted.

Conductive glue would be great. How conductive is this stuff?

Soldering doesn't seem to be an option since it's down inside of the
hole.

VH


If you don't have a stub sticking out, what do you have?

GWE

" wrote in message
ups.com...
I wish I had a stub sticking out.

The post broke off about 1/2 cm inside the speaker. I have the
broken
off piece and a hole with the other half inside. There is no way to
extract the other piece since it is soldered in and the circuitry is
potted.

Conductive glue would be great. How conductive is this stuff?

Soldering doesn't seem to be an option since it's down inside of the
hole.

VH


Tin the end of the pin with some solder, leaving a ball at the end.
Put the pin back in the hole, then heat it up again.

Use a little butane pencil torch...

"Rick" wrote in message
nk.net...

" wrote in message
ups.com...
I wish I had a stub sticking out.

The post broke off about 1/2 cm inside the speaker. I have the
broken
off piece and a hole with the other half inside. There is no way
to
extract the other piece since it is soldered in and the circuitry
is
potted.

Conductive glue would be great. How conductive is this stuff?

Soldering doesn't seem to be an option since it's down inside of
the
hole.

VH


Tin the end of the pin with some solder, leaving a ball at the end.
Put the pin back in the hole, then heat it up again.

Use a little butane pencil torch...


And if the broken piece is too short to work with, go to the store and
buy an 8-32 or 10-32 brass machine screw (whatever fits in the hole)
and use that as the replacement stud...

" wrote: (clip) Any help would be greatly appreciated. email
replies greatly appreciated.
^^^^^^^^^^^^
How about dropping a small coil spring in the hole, and then inserting the
broken off post? Perhaps a spring from a ball-point pen, or similar. Then
hold everything in place with some ingenious solution you come up with, such
as: 1.) string 2.) Hot glue 3.) C/A glue 4.) Tie wrap 5.) Very small clamp,
etc.

Could you run in a small self-tapping screw until it makes contact with the
broken, hidden stub, and then attach your speaker wire to that?

Or, drill and tap the hole to accept an appropriate length of all-thread.
Then tie your speaker wire to it with two nuts.

real address posted wrote:
I'm hoping that the metalworking community can help me out. I no
nothing about this subject but would like some advice.

Help these folks out with a couple pictures, would be my advice.

Here's how. Tape a ruler next to the part in question (and the
part that broke off) and snap two or three pictures (various angles).

Upload the pictures to the metalworking dropbox using the procedure
shown in: http://www.metalworking.com/dropbox.html

Repost your question, referring to the photo's URL (for instance):

"Hi all.

Could you please look at:
http://www.metalworking.com/DropBox/broketerminal.txt
http://www.metalworking.com/DropBox/broketerminal1.JPG
http://www.metalworking.com/DropBox/broketerminal2.JPG
http://www.metalworking.com/DropBox/broketerminal3.JPG

and tell me how to fix this myself?"

From what you've said so far, I expect that you need to use freeze
mist, some penetrating oil and a 'left hand drill' to shrink and back
the broken part out of the assembly. Match the threads with those from
a cut-off piece of brass machine screw and a nut.

Don't laugh, look at the bottom of page 2281 of the McMaster catalog for
the proper size bit that you use with the drill motor *in reverse*.

http://www.mcmaster.com/ Search term: left hand drill

--Winston

I'd grab my Dremel with a small dentist bit in it and start cleaning out
around the stud so that I could get at it. Epoxy later can fill the hole.
Be carefull as the binding post may be soldered to a printed circuit board
rather than a wire.
Then, after finding the wire, solder to the wire a new binding post. The
binding post is probalby a 5 way post that Radio Shack sells.
Short of that, you probbaly don't have enough meat inside to do a good job
of drilling and tapping a new hole as just inside there is usually a smaller
section where the soldering is actually done onto the post.
Don't bother with the conductive epoxies as their conductivity isn't good
enough to do a good job of conducting the current that the speaker will be
using. Take the number of watts that the speaker is rated for and divide by
8 for the amps of current that the speaker uses and you may be supprised at
how much current that the speaker uses and consider that you go and buy low
resistance wire just to make the speaker sound good. Any resistance in the
path decreases the volume and increases the resonant points of the speaker
which makes it sound bad.
I'll note that the potting is to keep others from copying the design and
this really doesn't work all that well as there are edpotting chemicals
available for alll of the various hard potting compounds. It just means
that the copyier needs to be a little more persistant.

--
Why do penguins walk so far to get to their nesting grounds?

Bob May wrote:
I'd grab my Dremel with a small dentist bit in it and start cleaning out
around the stud so that I could get at it. Epoxy later can fill the hole.
Be carefull as the binding post may be soldered to a printed circuit board
rather than a wire.
Then, after finding the wire, solder to the wire a new binding post. The
binding post is probalby a 5 way post that Radio Shack sells.
Short of that, you probbaly don't have enough meat inside to do a good job
of drilling and tapping a new hole as just inside there is usually a smaller
section where the soldering is actually done onto the post.
Don't bother with the conductive epoxies as their conductivity isn't good
enough to do a good job of conducting the current that the speaker will be
using. Take the number of watts that the speaker is rated for and divide by
8 for the amps of current that the speaker uses and you may be supprised at
how much current that the speaker uses and consider that you go and buy low
resistance wire just to make the speaker sound good. Any resistance in the
path decreases the volume and increases the resonant points of the speaker
which makes it sound bad.

I was about to strongly suggest he use conductive epoxy to join the
broken parts when I read your comment. Conductive epoxy has saved my
chops quite a few times when I didn't dare apply soldering heat to
someting, and once when the magnet wire I needed to reconnect turned out
to be made from aluminum. (I just reminded myself of the Korean war era
when I used to run into TV deflection yokes and power transformers wound
with enameled coated aluminum magnet wire, because copper was needed for
the war effort.)

Conductive epoxy is expensive, but I've had the same two little tubes of
the stuff sitting in the kitchen freezer for at least a dozen years now,
and usually just "a little dab will do ya".. It still works as good as
it did when I bought it after about ten minutes warming up the two tubes
in my pants pocket.

Before packing it in I Googled up some specs on conductive epoxies and
found their volume resistivities are claimed to be around .001 ohm-cm.

Now, copper is about 1000 times lower in resistance than that so at
first what you said about adding too much series resistance in the
speaker circuit almost scared me off.

But, I don't give up that easily, and decided to work it out. Suppose
the broken post is about 5mm in diameter and he can butt join the two
broken ends together with a layer of conductive epoxy averaging say
0.5mm thick.

If I just did the math right the series resistance of that layer of
epoxy will be only about 0.25 milliohm.

Number 12 copper wire has a resistance of about 2 milliohms per foot, so
it seems like that layer of conductive epoxy will have no more effect
than adding another couple of inches of that kind of wire to the speaker
leads, hardly a major worry, 'eh?

I don't claim to be an expert on this stuff, and I never even played one
on TV, and maybe there's some "contact resistance" factor or something
else I don't know of that sneaks up to grab you at the epoxy-metal
interface. But if there isn't, than I don't see why conductive epoxy
won't do the job for him safely, particularly if he can buttress and
protect the part he's joining back on so that it's not likely to bust
off again.

If the OP can satisfy himself that it's safe to drill a hole a short
distance down the center of the remaining piece and drills a similar
hole in the broken off piece, then he could splint the epoxy joint with
a short piece clipped off a No.4 brass machine screw and add strength.

Just my .02,

Jeff





--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

"Bob May" wrote: (clip) Take the number of watts that the speaker is rated
for and divide by 8 for the amps of current that the speaker uses and you
may be supprised at how much current that the speaker uses (clip)
^^^^^^^^^^^^^^^
In order for that to be true, 8 would have to be the volts at rated power.
Where did you get that figure? By any chance, did you use 8 because it is
an 8 ohm circuit? That wouldn't be right, then. If you want to work with
the power formula with the figures that are known, use P = I^2Z, where Z is
the speaker impedance of 8 ohms. So P = 8I^2, or I = square root (P/8).

On 19 Aug 2005 23:11:09 -0700, "
wrote:

I'm hoping that the metalworking community can help me out. I no
nothing about this subject but would like some advice.

I broke the speaker binding post on a very expensive and very heavy
subwoofer (A Wilsong Audio Puppy) The post is about 3-4mm diameter. I
can't remove the piece that is still embedded in the speaker because it
is soldered in and the circuitry is inaccessably potted. To ship to the
manufacturer and have them fix would be very expensive.

I'm thinking that my solution may be to drill a core and tap both ends
of the broken pin and connect them with a (conductive) headless bolt.

Would my local machine shop be able to do this and how much should I
expect to pay? I'm on the San Francisco peninsula.

I still get electrical contact when I insert the pin but I'm not happy
with this solution.

Any help would be greatly appreciated. email replies greatly
appreciated.

A machineshop certainly should be able to do this, as could many
amateur machinists. There are several readers of this group in the
bay area, TBD whether any would like to go for it for maybe a case of
beer or ???. I would, but I'm in Minneapolis -- when I'm not gone
fishin' this time of year.

Being a non-metalworker, you will very probably screw this up without
the right tools and skills. That isn't meant to be a put down by any
means, merely that we metalworkers have learned from the screwups on
our own projects. Exactly how to do your job isn't clear
without good photos or a first-hand look, but it doesn't sound like a
difficult job. I suspect I'd use a vertical mill or a shop-made jig.

For what it's worth, the speakers are rated at 4 ohms.

Leo Lichtman wrote:
"Bob May" wrote: (clip) Take the number of watts that the speaker is rated
for and divide by 8 for the amps of current that the speaker uses and you
may be supprised at how much current that the speaker uses (clip)
^^^^^^^^^^^^^^^
In order for that to be true, 8 would have to be the volts at rated power.
Where did you get that figure? By any chance, did you use 8 because it is
an 8 ohm circuit? That wouldn't be right, then. If you want to work with
the power formula with the figures that are known, use P = I^2Z, where Z is
the speaker impedance of 8 ohms. So P = 8I^2, or I = square root (P/8).

Thanks for all the replies. I'll try to post some photos later today.

I took some advice from the forum and put a ball of solder on the end
of the stub. I then inserted this into the hole and held a soldering
iron to the post. I had practiced before doing this and learned that
the solder on the tip (about 1 cm away) melts after about 36 seconds.

So I held the soldering iron onto the pin in place for about 45 seconds
and things seem to work now. I'm not altogether happy with this
solution and would like to find someone who could join the two pieces
together with a highly conductive post. This is an audiophile grade
system and I don't like my band-aid solution. I don't relish the idea
of shipping a 130lb speaker back to Utah for repairs though.

Anyone in the bay area want to take on this project or recommend a
place? Let me know what it would take.

Thanks!

" wrote: (clip) things seem to work now. I'm not altogether
happy with this solution (clip)
^^^^^^^^^^^^^^^^
If you had left it for repair at a professional "audiophile grade" shop,
they might have done the same thing, and charged you $85. And you WOULD be
happy. So, just send me the $85, if that is what it takes. I would have
done it for less, but as the psychiatrist said, "The fee is an important
part of the treatment."

Leo Lichtman wrote:
" wrote: (clip) things seem to work now. I'm not altogether
happy with this solution (clip)
^^^^^^^^^^^^^^^^
If you had left it for repair at a professional "audiophile grade" shop,
they might have done the same thing, and charged you $85. And you WOULD be
happy. So, just send me the $85, if that is what it takes. I would have
done it for less, but as the psychiatrist said, "The fee is an important
part of the treatment."




Second that...

As they say down Maine, "Pretty is as pretty does."

The Brooklyn equivalent of that serves as my definition of pragmatism,
"If it woiks, use it."

Stop worrying until it breaks again...

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

The problem is that with only solder holding it together it breaks with
any type of stress on the pin, if I move the speaker, the solder
breaks. I would also like to use a spade connector instead of the
banana clip connector. If I tried to use a spade connector now it would
pull the pin out.

Ultimately I think I want to splint the pieces together with a post or
headless bolt placed in a hole drilled concentrically down both pieces.

I'm willing to pay to have the post fabricated out of gold or whatever.
This is a very high end speaker.

I'll upload pics tonight.

wrote:

The problem is that with only solder holding it together it breaks with
any type of stress on the pin, if I move the speaker, the solder
breaks. I would also like to use a spade connector instead of the
banana clip connector. If I tried to use a spade connector now it would
pull the pin out.

Ultimately I think I want to splint the pieces together with a post or
headless bolt placed in a hole drilled concentrically down both pieces.

I'm willing to pay to have the post fabricated out of gold or whatever.
This is a very high end speaker.

I'll upload pics tonight.


Sorry, you didn't say it broke off that easily, just that you weren't
happy with it. We'll await the photos and pontificate further. G

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

On 22 Aug 2005 15:12:36 -0700, "
wrote:

The problem is that with only solder holding it together it breaks with
any type of stress on the pin, if I move the speaker, the solder
breaks. I would also like to use a spade connector instead of the
banana clip connector. If I tried to use a spade connector now it would
pull the pin out.

Ultimately I think I want to splint the pieces together with a post or
headless bolt placed in a hole drilled concentrically down both pieces.

I'm willing to pay to have the post fabricated out of gold or whatever.
This is a very high end speaker.

Why would you want gold? You are aware that gold has higher
resistivity than copper, right?

Matter of fact, I think Wilson uses stainless steel hardware.
http://www.stereophile.com//interviews/478/

That may be why you're not having good luck with ordinary solder.
It doesn't wet stainless well at all. You might have better luck
with a tin-silver solder of similar melting point but considerably
more strength and far better wetting of stainless.

I would suggest that you separate the matters of electrical
conductivity and mechanical strength. You are not going to get the
strength of the original part with a "splint", so if you broke the
original it's nearly a certainty that you'll eventually break the
repair unless it's mechanically reinforced.

Make the electrical connection with silver-tin solder, conductive
epoxy or whatever, provide mechanical strength by other means: a
flange with screws into the body or whatever.

Don Foreman wrote:



Why would you want gold? You are aware that gold has higher
resistivity than copper, right?

C'mon Don give him some slack...He said he was a non-metalworker.

I betcha he jut got misled because those who flog high end audio stuff
brag about gold plated connectors and he just thought it was because
gold had lower resistivity, when it's really put there for corrosion
resistance.


snipped


Make the electrical connection with silver-tin solder, conductive
epoxy or whatever, provide mechanical strength by other means: a
flange with screws into the body or whatever.



Yep, you can easily guess what I'd do....

Use conductive epoxy to glue in a stranded wire pigtail and get some
mechanical bend relief, and then solder a binding post to the free end
of that wire. Further messing around mechanically or thermally with
what's left of that post may lead to the internal disaster he was
worried about.

Who sits around staring at the backside of their speakers anyway? Once
again I say, "Pretty is as pretty does."G

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

On Tue, 23 Aug 2005 11:54:48 -0400, Jeff Wisnia
wrote:

Don Foreman wrote:



Why would you want gold? You are aware that gold has higher
resistivity than copper, right?

C'mon Don give him some slack...He said he was a non-metalworker.

I meant no disrespect. Ya don't have to be a metalworker to look up
resistivity in a book. I was surprised when I looked up the
resistivities. I thought I was going to say that gold isn't enough
better than copper to make any difference in a speaker termination.

Then I discovered that Wilson (not Wilsong) uses stainless
terminations. That happened because Mr. Wilson saw some audio gear
in Mazatlan with terminations so corroded they were green.

Imagine what partial rectification might do to your $4400 sound...
Tawk about distortion!

If a guy had more time than money (like me) and further had
audiophile zeal for the best possible repair ..... I may have an
idea.

It would take some experimenting to get the process right, but I
wonder if one could make a fixture to spin-braze the joint.
Liberally "tin" the end of the new (stainless) post with a strong
silverbrazing material like H&H Easy-Flo 45. After tinning, machine
the new post round in the lathe so there's a "slug" of silverbraze
material fused to the end. Then, with fixture holding the parts
parallel and concentric, spin the pin with axial pressure so friction
at the point of contact melts the silverbrazing material. Then
abruptly stop the spin. Result: a strong butt-braze that is
probably very nearly as strong as the parent material, with only very
localized heat due to the rapidity of the operation and the specific
heat and relatively low thermal conductivity of the materials being
joined. Electrical properties of such a joint would be excellent.

One could then brush-plate the new pin (or spade) with gold if
desired.

I really don't know if this would work, but I do know that
spin-welding is done as a production process.

"Don Foreman" wrote: (clip) It would take some experimenting to get the
process right, but I wonder if one could make a fixture to spin-braze the
joint. (clip)
^^^^^^^^^^^^^^
I think your idea could be made to work, with adequate preparation. My idea
is an outgrowth of yours, and could possibly be a little easier. Instead of
"spin-brazing" how about "spot-brazing?" Use an electrical spot welder to
melt the filler material, instead of friction. It would not require the
alignment jig, nor the rotary input power. You would have to find someone
with a spot welder and a cooperative attitude, however.

On Tue, 23 Aug 2005 18:04:09 GMT, "Leo Lichtman"
wrote:


"Don Foreman" wrote: (clip) It would take some experimenting to get the
process right, but I wonder if one could make a fixture to spin-braze the
joint. (clip)
^^^^^^^^^^^^^^
I think your idea could be made to work, with adequate preparation. My idea
is an outgrowth of yours, and could possibly be a little easier. Instead of
"spin-brazing" how about "spot-brazing?" Use an electrical spot welder to
melt the filler material, instead of friction. It would not require the
alignment jig, nor the rotary input power. You would have to find someone
with a spot welder and a cooperative attitude, however.

What do you connect the other electrode to? The broken pin is down
in a hole.

I would worry about blowing the voice coil and/or affecting the
magnet with the current pulse.

I got an email response from the customer support. The guy said the
spoke with production and they told him it was possible to get to the
pin in question by using a dremel tool on the expoxy potting. The pin
seems to be broken within the wall of the speaker (about 5/8 inch
thick, corian like material). I've carefully dremelled enough material
away(about 1/2 inch depth) to see a bit of the rest of the pin.

Now I'm taking a break before I screw things up. I understand that one
can really f**k things up with a dremel tool.

I've ordered a replacement pin through a dealer so I can see what I'm
dealing with.

What I think I might do is get some more of the pin exposed and find a
place where I can place a proper solder point. I would then cut the
original pin at that point, cut the replacement pin to match and solder
them together. I'm sure this will be stronger than what I'm doing now
since when I pull the pin out in it's current state of disrepair there
is solder bonded to the external portion which I heated; it appears the
solder is not well bonded to the stump embedded in the speaker,
probably since that part isn't hot.

OK. I've finally uploaded pics to the dropbox. They are labelled
starting "broken speaker...".

There is a text file explaining the pics as well.

The item in the picture that is not a speaker post is a 4/40 x 3/8
headless hex screw that I considered using as an internal fixating
device assuming I could find someone to drill and tap the existing ends
of the broken post.

Thanks for all the input!

Ooops, make that "vh broken..." for the filenames.

On 23 Aug 2005 13:58:15 -0700, "
wrote:

I got an email response from the customer support. The guy said the
spoke with production and they told him it was possible to get to the
pin in question by using a dremel tool on the expoxy potting. The pin
seems to be broken within the wall of the speaker (about 5/8 inch
thick, corian like material). I've carefully dremelled enough material
away(about 1/2 inch depth) to see a bit of the rest of the pin.

Now I'm taking a break before I screw things up. I understand that one
can really f**k things up with a dremel tool.

I've ordered a replacement pin through a dealer so I can see what I'm
dealing with.

What I think I might do is get some more of the pin exposed and find a
place where I can place a proper solder point. I would then cut the
original pin at that point, cut the replacement pin to match and solder
them together. I'm sure this will be stronger than what I'm doing now
since when I pull the pin out in it's current state of disrepair there
is solder bonded to the external portion which I heated; it appears the
solder is not well bonded to the stump embedded in the speaker,
probably since that part isn't hot.

Now you're getting somewhere!

Can you tell if the broken pin is made of stainless steel? If not,
do you have a broken off piece that someone could examine?

You'd probably get a stronger joint if you have a bushing or collar
made that would enclose both the stub and the new pin -- or have a pin
made that has a larger section with a hole that surrounds the stub.

If you can accurately measure the diameter of the stub (with calipers,
not a ruler) and make a sketch, I would be glad to machine a part for
you. Contact me by email if that is of interest.

If the material is stainless steel, then I would recommend a
tin-silver solder for joining them. I could send you a bit of that.
It melts at 430F, not greatly different from ordinary lead-tin solder,
but it is a lot stronger and it wets just about any ferrous or
copper-bearing metal -- steel, stainless, copper or brass.

On 23 Aug 2005 13:58:15 -0700, "
wrote:

I got an email response from the customer support. The guy said the
spoke with production and they told him it was possible to get to the
pin in question by using a dremel tool on the expoxy potting. The pin
seems to be broken within the wall of the speaker (about 5/8 inch
thick, corian like material). I've carefully dremelled enough material
away(about 1/2 inch depth) to see a bit of the rest of the pin.

Now I'm taking a break before I screw things up. I understand that one
can really f**k things up with a dremel tool.

I've ordered a replacement pin through a dealer so I can see what I'm
dealing with.

What I think I might do is get some more of the pin exposed and find a
place where I can place a proper solder point. I would then cut the
original pin at that point, cut the replacement pin to match and solder
them together. I'm sure this will be stronger than what I'm doing now
since when I pull the pin out in it's current state of disrepair there
is solder bonded to the external portion which I heated; it appears the
solder is not well bonded to the stump embedded in the speaker,
probably since that part isn't hot.

I looked at the pictures. Looks like the material is copper. Are
there any threads on the stub at the bottom of the hole? If you can
dremel out enough material, a new part could be made that has a
drilled and tapped hole to engage the threaded (?) stub. Three
threads would be enough.

If the replacement part were knurled on the outside and the hole was
then backfilled with epoxy after the part were screwed onto the stub,
I think you'd have a repair that would be sound both mechanically and
electrically.

I would make the replacement part of brass, rather than copper.
There's enough cross-sectional area that the resistance would still be
negligable, and it would be somewhat stronger than copper.

This could have a spade lug rather than be a binding post, if you
like. I could plate it with tin or nickel -- or gold, if you
wanted to buy the juice.

Don Foreman wrote:
On 23 Aug 2005 13:58:15 -0700, "
wrote:


I got an email response from the customer support. The guy said the
spoke with production and they told him it was possible to get to the
pin in question by using a dremel tool on the expoxy potting. The pin
seems to be broken within the wall of the speaker (about 5/8 inch
thick, corian like material). I've carefully dremelled enough material
away(about 1/2 inch depth) to see a bit of the rest of the pin.

Now I'm taking a break before I screw things up. I understand that one
can really f**k things up with a dremel tool.

I've ordered a replacement pin through a dealer so I can see what I'm
dealing with.

What I think I might do is get some more of the pin exposed and find a
place where I can place a proper solder point. I would then cut the
original pin at that point, cut the replacement pin to match and solder
them together. I'm sure this will be stronger than what I'm doing now
since when I pull the pin out in it's current state of disrepair there
is solder bonded to the external portion which I heated; it appears the
solder is not well bonded to the stump embedded in the speaker,
probably since that part isn't hot.


I looked at the pictures. Looks like the material is copper. Are
there any threads on the stub at the bottom of the hole? If you can
dremel out enough material, a new part could be made that has a
drilled and tapped hole to engage the threaded (?) stub. Three
threads would be enough.

If the replacement part were knurled on the outside and the hole was
then backfilled with epoxy after the part were screwed onto the stub,
I think you'd have a repair that would be sound both mechanically and
electrically.

I would make the replacement part of brass, rather than copper.
There's enough cross-sectional area that the resistance would still be
negligable, and it would be somewhat stronger than copper.

This could have a spade lug rather than be a binding post, if you
like. I could plate it with tin or nickel -- or gold, if you
wanted to buy the juice.

From the photos, I'm thinking there's a nut back there, one of two
securing the double binding post to that "Corian like" stuff he
mentioned. Could well be something just like the "Vampire BP2" a ways
down on this page:

http://www.welbornelabs.com/speakerstuff.htm

And, screwed into the nut is the remaining male threaded part of the
busted post, with a wire soldered to it's back end in typical binding
post fashion. Or, maybe they used a solder lug under the nut, with the
speaker/crossover lead wire soldered or crimped to it, in which case
removing enough of the plastic ought to let you access the surface of
that solder lug.

If they didn't use a solder lug and he drilled into and peeled out the
existing threaded stub to to be able to screw something into the threads
of that nut, he'd likely disconnect the back end of the stub from the
nut. I don't like that.

I'll raise my voice again and scream CONDUCTIVE EPOXY! I think I showed
a couple of days ago that the added series resistance would be
insignificant.

I (who can spend three hours fashioning and splinting on a replacement
foot of an antique ivory asian "medicine lady", missing when I bought
it) can appreciate why the OP eants to keep the original appearance of
his speaker by connecting a pigtail lead with conductive epoxy as I
suggested, even though I think that's the best way to avoid fracturing
the conductive epoxy when connecting a lead to the speaker.

My "second best" suggestion is to reconnect the present broken binding
post back onto whatever metal is there *without* trying to drill into
it, and use conductive epoxy to make the connection.

I'd suggest Dremeling a couple of "keyways" into the existing plastic
binding post base because it's likely to be made of some thermoplastic
epoxy won't like to stick to, and there's a fair amount of torque
exerted when the binding post finger nut is tightened. (Maybe even
enough to be what caused that busted post in the first place?) I'd use
enough conductive epoxy to make the connection and squeeze up around the
post, removing whatever bubbles over.

Whatever method he ends up using, he'd better be gentle about tightening
the finger nut on that post. Using bannana plugs on the end of the
speaker leads might be the safest choice.

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

Don Foreman wrote:

On 22 Aug 2005 15:12:36 -0700, "
wrote:


The problem is that with only solder holding it together it breaks with
any type of stress on the pin, if I move the speaker, the solder
breaks. I would also like to use a spade connector instead of the
banana clip connector. If I tried to use a spade connector now it would
pull the pin out.

Ultimately I think I want to splint the pieces together with a post or
headless bolt placed in a hole drilled concentrically down both pieces.

I'm willing to pay to have the post fabricated out of gold or whatever.
This is a very high end speaker.


Why would you want gold? You are aware that gold has higher
resistivity than copper, right?

Gold is wanted for several reasons on many items.
1. it is a noble metal - that is, not much dissolves it.
2. It flows on contact with more gold or a metal it likes (most).
3. It forms a gas tight fit - so the chlorine in the air doesn't etch copper...
4. It can be plated on so thinly.
5. It looks nice.

Martin


Matter of fact, I think Wilson uses stainless steel hardware.
http://www.stereophile.com//interviews/478/

That may be why you're not having good luck with ordinary solder.
It doesn't wet stainless well at all. You might have better luck
with a tin-silver solder of similar melting point but considerably
more strength and far better wetting of stainless.

I would suggest that you separate the matters of electrical
conductivity and mechanical strength. You are not going to get the
strength of the original part with a "splint", so if you broke the
original it's nearly a certainty that you'll eventually break the
repair unless it's mechanically reinforced.

Make the electrical connection with silver-tin solder, conductive
epoxy or whatever, provide mechanical strength by other means: a
flange with screws into the body or whatever.











--
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
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On Tue, 23 Aug 2005 21:18:01 -0400, Jeff Wisnia
wrote:

Don Foreman wrote:
On 23 Aug 2005 13:58:15 -0700, "
wrote:


I got an email response from the customer support. The guy said the
spoke with production and they told him it was possible to get to the
pin in question by using a dremel tool on the expoxy potting. The pin
seems to be broken within the wall of the speaker (about 5/8 inch
thick, corian like material). I've carefully dremelled enough material
away(about 1/2 inch depth) to see a bit of the rest of the pin.

Now I'm taking a break before I screw things up. I understand that one
can really f**k things up with a dremel tool.

I've ordered a replacement pin through a dealer so I can see what I'm
dealing with.

What I think I might do is get some more of the pin exposed and find a
place where I can place a proper solder point. I would then cut the
original pin at that point, cut the replacement pin to match and solder
them together. I'm sure this will be stronger than what I'm doing now
since when I pull the pin out in it's current state of disrepair there
is solder bonded to the external portion which I heated; it appears the
solder is not well bonded to the stump embedded in the speaker,
probably since that part isn't hot.


I looked at the pictures. Looks like the material is copper. Are
there any threads on the stub at the bottom of the hole? If you can
dremel out enough material, a new part could be made that has a
drilled and tapped hole to engage the threaded (?) stub. Three
threads would be enough.

If the replacement part were knurled on the outside and the hole was
then backfilled with epoxy after the part were screwed onto the stub,
I think you'd have a repair that would be sound both mechanically and
electrically.

I would make the replacement part of brass, rather than copper.
There's enough cross-sectional area that the resistance would still be
negligable, and it would be somewhat stronger than copper.

This could have a spade lug rather than be a binding post, if you
like. I could plate it with tin or nickel -- or gold, if you
wanted to buy the juice.

From the photos, I'm thinking there's a nut back there, one of two
securing the double binding post to that "Corian like" stuff he
mentioned. Could well be something just like the "Vampire BP2" a ways
down on this page:

http://www.welbornelabs.com/speakerstuff.htm

And, screwed into the nut is the remaining male threaded part of the
busted post, with a wire soldered to it's back end in typical binding
post fashion. Or, maybe they used a solder lug under the nut, with the
speaker/crossover lead wire soldered or crimped to it, in which case
removing enough of the plastic ought to let you access the surface of
that solder lug.

If they didn't use a solder lug and he drilled into and peeled out the
existing threaded stub to to be able to screw something into the threads
of that nut, he'd likely disconnect the back end of the stub from the
nut. I don't like that.

Me either. My suggestion was not to drill the stub, but to have
something made that screws onto it.

I'll raise my voice again and scream CONDUCTIVE EPOXY! I think I showed
a couple of days ago that the added series resistance would be
insignificant.

Unless it cracks over time, due to different rates of thermal
expansion of metal and epoxy.


I'd suggest Dremeling a couple of "keyways" into the existing plastic
binding post base because it's likely to be made of some thermoplastic
epoxy won't like to stick to, and there's a fair amount of torque
exerted when the binding post finger nut is tightened. (Maybe even
enough to be what caused that busted post in the first place?) I'd use
enough conductive epoxy to make the connection and squeeze up around the
post, removing whatever bubbles over.

Good idea. I'd knurl the insert too. Then there's no dependence on
adhesion of the epoxy, it forms a mechanical lock by interference fit
when it cures. I might also mill some flats on the outside of the
post where it emerges, so a little wrench could hold it while leads
were being torqued.

Whatever method he ends up using, he'd better be gentle about tightening
the finger nut on that post. Using bannana plugs on the end of the
speaker leads might be the safest choice.

I'd include wrench flats to hold the post while tightening. Problem
with banannas is that they project, providing a lever to bonk and
break. Wires are more flexible.

Jeff

Don Foreman wrote:

snipped

If they didn't use a solder lug and he drilled into and peeled out the
existing threaded stub to to be able to screw something into the threads
of that nut, he'd likely disconnect the back end of the stub from the
nut. I don't like that.


Me either. My suggestion was not to drill the stub, but to have
something made that screws onto it.

I find it hard to believe that he was lucky enough to have that post
break so that there was still some of the threaded part sticking out
before the nut. In my experience stuff like that tends to break about
three quarters of a thread turn down inside the nut. But, if he was,
then your idea of screwing a threaded piece over it is preferable to
just relying on conductive epoxy, but I'd use that epoxy too, it
probably couldn't hurt.

I'll raise my voice again and scream CONDUCTIVE EPOXY! I think I showed
a couple of days ago that the added series resistance would be
insignificant.


Unless it cracks over time, due to different rates of thermal
expansion of metal and epoxy.

Hasn't happened to me yet. Besides, how big a temperature swing is an
indoor louspeaker liable to see?



I'd suggest Dremeling a couple of "keyways" into the existing plastic
binding post base because it's likely to be made of some thermoplastic
epoxy won't like to stick to, and there's a fair amount of torque
exerted when the binding post finger nut is tightened. (Maybe even
enough to be what caused that busted post in the first place?)

Guess it wasn't just his finger torque, in the text file he posted with
the three photos he tells how it happened when he was using "a tool" to
tighten the post.


I'd use
enough conductive epoxy to make the connection and squeeze up around the
post, removing whatever bubbles over.


Good idea. I'd knurl the insert too. Then there's no dependence on
adhesion of the epoxy, it forms a mechanical lock by interference fit
when it cures.

Looks like from viewing his first photo that the part is already
knurled. Likely that's likely the section around which the plastic dual
binding posts "base" was molded, for obvious reasons.

I might also mill some flats on the outside of the
post where it emerges, so a little wrench could hold it while leads
were being torqued.


Whatever method he ends up using, he'd better be gentle about tightening
the finger nut on that post. Using bannana plugs on the end of the
speaker leads might be the safest choice.


I'd include wrench flats to hold the post while tightening.

Yeah, but what are the chances that wrench will get used every time? I
wouldn't depend on it, even if it was me who owned that speaker. Well,
maybe if I left a dedicated little wrench hanging on a string at the
back of the speaker to wake up my memory.


Problem with banannas is that they project, providing a lever to bonk and
break. Wires are more flexible.

Now we're back to my wanting him to use conductive epoxy to fasten in a
flexible pigtail. G


Jeff (Who is thinking, "Jeez, if we got paid by the hour for all this
thinkin' time we'd fer sure be 'fartin on silk', as they say down Maine.)

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

On Wed, 24 Aug 2005 00:11:22 -0400, Jeff Wisnia
wrote:



Yeah, but what are the chances that wrench will get used every time? I
wouldn't depend on it, even if it was me who owned that speaker. Well,
maybe if I left a dedicated little wrench hanging on a string at the
back of the speaker to wake up my memory.

Bet you would, if you'd written the check for the speaker and then had
to fix it or get it fixed.

I wonder if they sound better if the little wrench is gold plated....
(ducking)

Thanks to all in the group for all the great advice and generous offers
to help. It's incredible how helpful the metalworking community has
been.

I have placed my order for conductive epoxy as I see this as the least
risky and least destructive means of getting a repair. I will also try
to use some silver/tin solder and see if this works better than the
lead based solder I've been using.

I can't tell what the posts are made of. Looks like a silver metal with
a gold plate.

In the long term I will also continue to slowly dremel away epoxy to
get to the post. When I get the replacement I'll upload a pic. I'm sure
that there is more post to work with since it broke off within the wall
of the speaker. Maybe if I'm careful and lucky with the dremel I'll be
able to expose enough threads to work with. Exposing enough post to cut
and then join ends together with a threaded sleeve sounds like a great
long term solution.

Any tips on what type of dremel head will cut epoxy but not damage the
post? Should I try to use any solvents when I get really close to the
post?

wrote:
Thanks to all in the group for all the great advice and generous offers
to help. It's incredible how helpful the metalworking community has
been.

I have placed my order for conductive epoxy as I see this as the least
risky and least destructive means of getting a repair. I will also try
to use some silver/tin solder and see if this works better than the
lead based solder I've been using.

I can't tell what the posts are made of. Looks like a silver metal with
a gold plate.

In the long term I will also continue to slowly dremel away epoxy to
get to the post. When I get the replacement I'll upload a pic. I'm sure
that there is more post to work with since it broke off within the wall
of the speaker. Maybe if I'm careful and lucky with the dremel I'll be
able to expose enough threads to work with. Exposing enough post to cut
and then join ends together with a threaded sleeve sounds like a great
long term solution.

Any tips on what type of dremel head will cut epoxy but not damage the
post? Should I try to use any solvents when I get really close to the
post?


I can't think of a rotating cutter which would guarantee your not
damaging the remaining part of the post if it touched it, but have you
tried "thermally excavating" the epoxy with a hot soldering iron tip?
Something around 3/16" diameter with a chisel shaped end ought to do it
if you dig carefully.

I do hope you get lucky and you find you can expose enough of the
threaded portion. Judging from the 4-40 setscrew in your photo, I'd
guess that the thread on the broken part (If it's US made) is likely to
be 6-32, in which case the chances of drilling and tapping it for
anything which could give you much strength aren't slim and none, and
Slim rode out of town yesterday. You'd be far better off using Don's
suggested threaded sleeve, once you identify just what the thread specs are.

I wouldn't recommend using chemicals to clean off the post, I just don't
know what the long term effects might be. You could probably get most of
the epoxy of the threaded part just by poking at it with a small sharp
tool, and if there is stuff left in the threads you could probably make
a small diameter erzats "die" to clean it up by taking a matching
threaded standoff (see below) and hacksawing a slot about 1/8" deep
across the diameter on one end.

You could probably buy a "reddy maid" brass standoff from one of many
places like this:

http://www.keyelco.com/products/specs/spec17.asp

And you could shorten a long one easily enought if you needed too, but
it's probably easier just to let one of us make one out of brass for you
and pop it in the mail once the thread specs and length are known.
That's only "the work of a moment" for Don, or even me, and (speaking
for myself) the satisfaction of knowing you helped somebody duck a
horrificly expensive commercial repair job is ample reward.

HTH,

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

On 23 Aug 2005 14:29:45 -0700, "
wrote:

Ooops, make that "vh broken..." for the filenames.


From the looks of jpg3 it appears the quick terms' are mounted on a
plate, attached to the speaker by four screws. What did you find when
you pulled the screws and plate? If that area isn't potted maybe the
terminal can be replaced as a unit.

Bob
rgentry_at_oz_dot_net
_AT_ = @, _dot_ = . to eMail

Bob,

The entire chamber housing the circuitry is potted with black epoxy.
I'm dremelling in where the potting is up against the wall of the
speaker where the pin inserts. It appears that the pin has broken off
inside of the wall of the speaker and extends a way into the potting.
I'll know more when I get a stock post to compare it to.

I've found the post (the sparks gave it away) and now I'm going to
dremel around it and pick away carefully using something like a dental
tool.

The plate can't be removed. I tried removing the screws, a heat gun and
some prying. The mfg says that the potting makes it impossible to
remove. They probably installed it along with a gasket and then poured
the potting in.

On 24 Aug 2005 08:13:19 -0700, "
wrote:

Thanks to all in the group for all the great advice and generous offers
to help. It's incredible how helpful the metalworking community has
been.

I have placed my order for conductive epoxy as I see this as the least
risky and least destructive means of getting a repair. I will also try
to use some silver/tin solder and see if this works better than the
lead based solder I've been using.

I can't tell what the posts are made of. Looks like a silver metal with
a gold plate.

Most commercial binding posts are made of brass. It would be
nickle-plated under the few microinches of gold. However, Wilson
says they use stainless steel hdwe, so it might be gold-plated
stainless steel. Gold can be plated directly onto stainless.

In the long term I will also continue to slowly dremel away epoxy to
get to the post. When I get the replacement I'll upload a pic. I'm sure
that there is more post to work with since it broke off within the wall
of the speaker. Maybe if I'm careful and lucky with the dremel I'll be
able to expose enough threads to work with. Exposing enough post to cut
and then join ends together with a threaded sleeve sounds like a great
long term solution.

Any tips on what type of dremel head will cut epoxy but not damage the
post? Should I try to use any solvents when I get really close to the
post?

About any dremel bit will cut metal about as readily as epoxy or
plastic.

I might make a little trepanning tool, like an end mill with a hole
in the middle. The hole would go over the stub, which would serve as
a guide. That would leave epoxy or plastic in the threads but remove
the material around the stub. I'd then try gritblasting the plastic
out of the threads with a airbrush-like blaster or "air eraser" as
http://www.paascheairbrush.com/sprayers_and_guns.html
and maybe glass beads. That would aggressively attack the plastic
without doing much to the metal other than clean it.

Chemicals that will attack epoxy are rather nasty and can leave a
gummy mess.

I wonder what would happen if one poked at the epoxy with a red-hot
wire or pick while shooting a jet of oxygen into the hole with a
jeweller's torch. I'd try that on a practice piece first, with CO2
or baking soda at hand to smother things if they got too vigorous.
I'd also do it in a very well-ventilated space.