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."