Making an Adaptor from the vintage single wire 5/8" screw on

Most of my vintage testers have those old style 5/8" screw on MIC
connectors. I have considered changing all of them to BNC and I see many
people do this, but I really dont feel like opening each tester to do
this, plus I kind of like keeping vintage gear original.

I have some probes with the MIC connectors, but there are times I'd like
to use a probe with a BNC on my vintage testers.

My idea is to simply make a few adaptors. I have several of the old MIC
connectors, and I have a bunch of the chassis mount BNC connectors
(which I believe is called the "female"). But I am not seeing any
INLINE female BNC connectors. If I could find these female INLINE ones,
I'd simply take a 6" piece of coax, and put the MIC connector on one end
and the BNC on the other. Making 2 or 3 of these should suffice.

Has anyone seen any female INLINE BNC connectors to buy?
Or, is there another method to accomplish this?

Yes, I could solder on the chassis type BNC connectors, but they would
lack shielding at the connector.

 

[Fox's Mercantile]

On 1/9/19 8:03 PM, tubeguy@myshop.com wrote:

Has anyone seen any female INLINE BNC connectors to buy?
Or, is there another method to accomplish this?

You can use these:
<https://www.ebay.com/itm/183118810685>

Or you can do what I did.
1. Remove spring from connector.
2. Drill out connector back with 11/32" drill.
3. Tap connector shell using 3/8-32 tap.
4. Solder #16 wire to solder cup on back of BNC female.
5. Stick wire through connect grommet in Amphenol connector.
6. Screw BNC into connector shell. Tighten.
7. Solder wire to Amphenol connector grommet.
8. Cut wire, smooth with file.

Presto! Instant, sort of, Amphenol Microphone to BNC adapter.

--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

[Dave M]

If you don't mind buying from Chinese sellers and waiting a month or so
for delivery, Ebay item 113114727770 is what you're after if you don't
have the tooling for a crimp style connector (Ebay # 323326819341).
Or, you could get several of these (Ebay # 392106541719) with the BNC
already assembled onto the cable, Just cut off the banana plugs and
solder your mic connectors onto the cable.

Cheers,
Dave M


On Wed, 09 Jan 2019 20:03:29 -0600, tubeguy@myshop.com wrote:

Most of my vintage testers have those old style 5/8" screw on MIC
connectors. I have considered changing all of them to BNC and I see many
people do this, but I really dont feel like opening each tester to do
this, plus I kind of like keeping vintage gear original.

I have some probes with the MIC connectors, but there are times I'd like
to use a probe with a BNC on my vintage testers.

My idea is to simply make a few adaptors. I have several of the old MIC
connectors, and I have a bunch of the chassis mount BNC connectors
(which I believe is called the "female"). But I am not seeing any
INLINE female BNC connectors. If I could find these female INLINE ones,
I'd simply take a 6" piece of coax, and put the MIC connector on one end
and the BNC on the other. Making 2 or 3 of these should suffice.

Has anyone seen any female INLINE BNC connectors to buy?
Or, is there another method to accomplish this?

Yes, I could solder on the chassis type BNC connectors, but they would
lack shielding at the connector.

 

[whit3rd]

On Wednesday, January 9, 2019 at 6:03:44 PM UTC-8, tub...@myshop.com wrote:

Most of my vintage testers have those old style 5/8" screw on MIC
connectors. I have considered changing all of them to BNC

Don't you want a UHF BNC adapter? Take a look at images.google.com with
that search string...

The UHF center socket takes a banana plug, so putting a ground banana compatible post
next to the coax connector can let you use a dual-banana-to-BNC as well.

 

[Jim Mueller]

On Wed, 09 Jan 2019 20:03:29 -0600, tubeguy wrote:

Most of my vintage testers have those old style 5/8" screw on MIC
connectors. I have considered changing all of them to BNC and I see many
people do this, but I really dont feel like opening each tester to do
this, plus I kind of like keeping vintage gear original.

I have some probes with the MIC connectors, but there are times I'd like
to use a probe with a BNC on my vintage testers.

My idea is to simply make a few adaptors. I have several of the old MIC
connectors, and I have a bunch of the chassis mount BNC connectors
(which I believe is called the "female"). But I am not seeing any
INLINE female BNC connectors. If I could find these female INLINE ones,
I'd simply take a 6" piece of coax, and put the MIC connector on one end
and the BNC on the other. Making 2 or 3 of these should suffice.

Has anyone seen any female INLINE BNC connectors to buy?
Or, is there another method to accomplish this?

Yes, I could solder on the chassis type BNC connectors, but they would
lack shielding at the connector.

You can remove the spring from the mic connector and drill the opening
out enough to remove the plating. Then take a single hole style BNC
connector and file the threads down until it fits in the mic connector.
Solder a wire onto the center of the BNC and feed it through the hole in
the mic connector. Then solder the BNC into the back of the mic
connector and solder the center contact. That's how I made mine. It
avoids having to come up with an unusual size tap.

--
Jim Mueller wrongname@nospam.com

To get my real email address, replace wrongname with eggmen.
Then replace nospam with expressmail. Lastly, replace com with dk.

 

[Fox's Mercantile]

On 1/10/19 8:59 PM, whit3rd wrote:

On Wednesday, January 9, 2019 at 6:03:44 PM UTC-8, tub...@myshop.com wrote:
Most of my vintage testers have those old style 5/8" screw on MIC
connectors. I have considered changing all of them to BNC


Don't you want a UHF BNC adapter? Take a look at images.google.com with
that search string...

The UHF center socket takes a banana plug, so putting a ground banana compatible post
next to the coax connector can let you use a dual-banana-to-BNC as well.

Except....A UHF connector is 5/8-24 pitch.
The Amphenol button connector is 3/8-27 pitch.
Unless you consider cross threading a feature, they are not compatible.

--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

On Fri, 11 Jan 2019 03:21:22 GMT, Jim Mueller <wrongname@nospam.com>
wrote:

On Wed, 09 Jan 2019 20:03:29 -0600, tubeguy wrote:

Most of my vintage testers have those old style 5/8" screw on MIC
connectors. I have considered changing all of them to BNC and I see many
people do this, but I really dont feel like opening each tester to do
this, plus I kind of like keeping vintage gear original.

I have some probes with the MIC connectors, but there are times I'd like
to use a probe with a BNC on my vintage testers.

My idea is to simply make a few adaptors. I have several of the old MIC
connectors, and I have a bunch of the chassis mount BNC connectors
(which I believe is called the "female"). But I am not seeing any
INLINE female BNC connectors. If I could find these female INLINE ones,
I'd simply take a 6" piece of coax, and put the MIC connector on one end
and the BNC on the other. Making 2 or 3 of these should suffice.

Has anyone seen any female INLINE BNC connectors to buy?
Or, is there another method to accomplish this?

Yes, I could solder on the chassis type BNC connectors, but they would
lack shielding at the connector.

You can remove the spring from the mic connector and drill the opening
out enough to remove the plating. Then take a single hole style BNC
connector and file the threads down until it fits in the mic connector.
Solder a wire onto the center of the BNC and feed it through the hole in
the mic connector. Then solder the BNC into the back of the mic
connector and solder the center contact. That's how I made mine. It
avoids having to come up with an unusual size tap.

I was holding both parts in hand and thinking about doing something like
that, except my thought was to epoxy the BNC into the Mic connector. (of
course making sure they fit tight so there is a good connection on the
ground side).

There have been lots of great suggestions in this thread!

 

[whit3rd]

On Thursday, January 10, 2019 at 7:24:54 PM UTC-8, Fox's Mercantile wrote:

On 1/10/19 8:59 PM, whit3rd wrote:

Don't you want a UHF BNC adapter? Take a look at images.google.com with
that search string...

Except....A UHF connector is 5/8-24 pitch.
The Amphenol button connector is 3/8-27 pitch.
Unless you consider cross threading a feature, they are not compatible.

Oh, then the 'easiest' solution I'm aware of is a pogo pin soldered in a BNC
fitting, and a lathe-job threaded tube, 3/8-27 to 38-32, to mate the threads.

I'm not sure I've ever encountered 3/8-27, but I have taps for 3/8-24./ -26. /-32

 

[whit3rd]

On Thursday, January 10, 2019 at 7:24:54 PM UTC-8, Fox's Mercantile wrote:

> The Amphenol button connector is 3/8-27 pitch.

Is this about the connector depicted here <https://archive.org/details/Amphenol/page/n5>
at the top left of page M-6 ?

 

[Fox's Mercantile]

On 1/11/19 5:37 PM, whit3rd wrote:

On Thursday, January 10, 2019 at 7:24:54 PM UTC-8, Fox's Mercantile wrote:

The Amphenol button connector is 3/8-27 pitch.

Is this about the connector depicted here <https://archive.org/details/Amphenol/page/n5
at the top left of page M-6 ?

Yes.

5/8-27 Industry standard.

--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

On Fri, 11 Jan 2019 15:21:54 -0800 (PST), whit3rd <whit3rd@gmail.com>
wrote:

On Thursday, January 10, 2019 at 7:24:54 PM UTC-8, Fox's Mercantile wrote:
On 1/10/19 8:59 PM, whit3rd wrote:

Don't you want a UHF BNC adapter? Take a look at images.google.com with
that search string...

Except....A UHF connector is 5/8-24 pitch.
The Amphenol button connector is 3/8-27 pitch.
Unless you consider cross threading a feature, they are not compatible.

Oh, then the 'easiest' solution I'm aware of is a pogo pin soldered in a BNC
fitting, and a lathe-job threaded tube, 3/8-27 to 38-32, to mate the threads.

I'm not sure I've ever encountered 3/8-27, but I have taps for 3/8-24./ -26. /-32

Lots of people who aren't machinists or who work with lamp fittings
could easily think that a 1/8-27 straight pipe thread is 3/8-27. This
is because 1/8-27 straight pipe thread has a major diameter of .394"
to .390", which is only .019" to .015" over the major diameter of a
3/8 thread. And as sloppy as some threads are made, especially the
threads on lamp fittings, the mistake is even easier to make. I have
had more than one person ask me to either tap holes for 3/8-27 or if I
knew where to buy a tap for that thread because they had no luck
looking in catalogs or online for the elusive 3/8-27 tap.
Eric

 

[Fox's Mercantile]

On 1/11/19 6:46 PM, etpm@whidbey.com wrote:

On Fri, 11 Jan 2019 15:21:54 -0800 (PST), whit3rd <whit3rd@gmail.com
wrote:

On Thursday, January 10, 2019 at 7:24:54 PM UTC-8, Fox's Mercantile wrote:
On 1/10/19 8:59 PM, whit3rd wrote:

Don't you want a UHF BNC adapter? Take a look at images.google.com with
that search string...

Except....A UHF connector is 5/8-24 pitch.
The Amphenol button connector is 3/8-27 pitch.

CORRECTION The Amphenol button connector is 5/8-27 pitch.

Unless you consider cross threading a feature, they are not compatible.

Oh, then the 'easiest' solution I'm aware of is a pogo pin soldered in a BNC
fitting, and a lathe-job threaded tube, 3/8-27 to 38-32, to mate the threads.

I'm not sure I've ever encountered 3/8-27, but I have taps for 3/8-24./ -26. /-32
Lots of people who aren't machinists or who work with lamp fittings
could easily think that a 1/8-27 straight pipe thread is 3/8-27. This
is because 1/8-27 straight pipe thread has a major diameter of .394"
to .390", which is only .019" to .015" over the major diameter of a
3/8 thread. And as sloppy as some threads are made, especially the
threads on lamp fittings, the mistake is even easier to make. I have
had more than one person ask me to either tap holes for 3/8-27 or if I
knew where to buy a tap for that thread because they had no luck
looking in catalogs or online for the elusive 3/8-27 tap.
Eric

--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

[Fox's Mercantile]

On 1/11/19 8:36 PM, Martin C. wrote:

I have never seen such a connector, but have read that the shell
thread is the same as a a PL259.
Could a common PL259 to BNC adaptor be modified?

They are NOT the same.
The common UHF connector is 5/8-24.
The Amphenol button connector is 5/8-27.


--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

On Fri, 11 Jan 2019 15:21:54 -0800 (PST), whit3rd <whit3rd@gmail.com>
wrote:

On Thursday, January 10, 2019 at 7:24:54 PM UTC-8, Fox's Mercantile wrote:
On 1/10/19 8:59 PM, whit3rd wrote:

Don't you want a UHF BNC adapter? Take a look at images.google.com with
that search string...

Except....A UHF connector is 5/8-24 pitch.
The Amphenol button connector is 3/8-27 pitch.
Unless you consider cross threading a feature, they are not compatible.

Oh, then the 'easiest' solution I'm aware of is a pogo pin soldered in a BNC
fitting, and a lathe-job threaded tube, 3/8-27 to 38-32, to mate the threads.

I'm not sure I've ever encountered 3/8-27, but I have taps for 3/8-24./ -26. /-32

Pogo pin???? What's that?

 

On Fri, 11 Jan 2019 15:37:36 -0800 (PST), whit3rd <whit3rd@gmail.com>
wrote:

On Thursday, January 10, 2019 at 7:24:54 PM UTC-8, Fox's Mercantile wrote:

The Amphenol button connector is 3/8-27 pitch.

Is this about the connector depicte, I d here <https://archive.org/details/Amphenol/page/n5
at the top left of page M-6 ?

Yes.

I would have been more descriptive in my original posting, but it seems
there are numerous names for them, and not a standard "name". But most
people seem to understand "vintage ONE pin MIC connector".

It seems a lot of people hate them, and want to replace all of them with
BNC. Personally, I like those oldies. Sure it takes a few seconds longer
to screw them on, but they worked well, and under normal use, they were
not changed all that often. Plus, they were versatile, since they were
both male and female, by using or removing the "ring". That alone was an
ingenious invention.

I may be wrong, but I believe they were originally designed for
microphone use, and later adapted for test gear connections. I can see
why they were later replaced by modern microphone connectors, having 3
connections, since the microphones needed better shielding and impedance
matching. But for use on test equip. they still work great.

The hardest part these days, is finding the connectors ends at a
reasonable price. Someone always has them on ebay, but usually at
ridiculous prices. From my understanding, they are no longer
manufactured, so all that exist are NOS. Fortunately I was able to buy 3
of them awhile back at a fair price and they were new in the package. I
now wish I had gotten a few more from the seller..... I think he had
around 10 of them total.

 

[Dave Platt]

In article <0lkq3etgnf7ud9l1o3eqedpvqs3285ih38@4ax.com>,
<tubeguy@myshop.com> wrote:

Oh, then the 'easiest' solution I'm aware of is a pogo pin soldered in a BNC
fitting, and a lathe-job threaded tube, 3/8-27 to 38-32, to mate the threads.

I'm not sure I've ever encountered 3/8-27, but I have taps for 3/8-24./ -26. /-32

Pogo pin???? What's that?

A two-piece (concentric cylinders) electrical contact. Think
"piece of brass rod, slid into a brass tube, with a spring at the
base".

See https://www.ebay.com/itm/261897100962 for one example of how
they're used. This is a JTAG connector with 8 pogo pins. It can be
pressed down onto an 8-pad through-hole pattern on the board
(preferable one populated with a machined-pin socket, although you
could probably make it work just with plated-through holes).

https://www.ebay.com/itm/SOIC-8-Spring-Loaded-Pogo-Pin-Adapter-Jtag/250464158353
is similar, for a SOIC pattern.