Author Topic: 1" x 20 tpi conduit thread ????  (Read 7618 times)

Offline awemawson

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1" x 20 tpi conduit thread ????
« on: January 27, 2014, 10:20:46 AM »
I have an Amphenol circular military style 10 pin plug, the back end of which is 1" x 20 tpi, and want to connect it to 20 mm UK flexible armoured conduit.

Is 1" x 20 tpi a standard American conduit thread by any chance ? If I have to turn up a converter I will but would rather avoid it if possible
« Last Edit: March 31, 2016, 08:25:33 AM by awemawson »
Andrew Mawson
East Sussex

Offline 75Plus

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Re: 1" x 20 tpi conduit thread ????
« Reply #1 on: January 28, 2014, 10:27:07 AM »
Andrew that is a UNEF thread (unified extra fine) There may be adapters to convert to UNF, fine or UNC, coarse but I have never ran across them. The UNEF thread is common on aircraft and military gear. Perhaps the fine threads are less prone to coming loose due to vibration. A lot of the devices using these threads are also are drilled for safety wire. Belt AND suspenders i suppose.

Joe

Offline awemawson

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Re: 1" x 20 tpi conduit thread ????
« Reply #2 on: January 28, 2014, 10:34:02 AM »
Thanks for the reply 75Plus.

I gave up searching and internally single point threaded a bit of brass this afternoon 1" 20 tpi at one end and 20mm conduit thread at the other.

I hate internal single point threading in blind holes, but it went well. It's all too easy to lose your threading tool on the 'back wall'  :bugeye:
Andrew Mawson
East Sussex

Offline Pete W.

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Re: 1" x 20 tpi conduit thread ????
« Reply #3 on: January 28, 2014, 10:41:25 AM »
Hi there, Andrew and Joe,

I thought they're UNEF because the die-cast aluminium alloy outlet accessories are thin-walled so as to save weight in avionics applications. 
Best regards,

Pete W.

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Offline 75Plus

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Re: 1" x 20 tpi conduit thread ????
« Reply #4 on: January 28, 2014, 11:27:57 AM »
The UNEF thread is also used on the bolts and nuts used to assemble aircraft.

As a side note, I know that we have several Ham Radio operators on the board and the antenna connectors for co-axial cable are UNEF threaded. I have however ran into some PL 259 connectors that were made with metric threads. They looked the same as 5/8-20 threads but would not thread onto the SO-239 socket.

Offline Pete W.

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Re: 1" x 20 tpi conduit thread ????
« Reply #5 on: January 28, 2014, 02:26:59 PM »
SNIP

As a side note, I know that we have several Ham Radio operators on the board and the antenna connectors for co-axial cable are UNEF threaded. I have however ran into some PL 259 connectors that were made with metric threads. They looked the same as 5/8-20 threads but would not thread onto the SO-239 socket.

Hi there, 75Plus,

I've just done a search for 'Amphenol SO239' and the best data sheet I found quotes 5/8" by 24 tpi UNEF.

I wrote 'just' but it was actually an hour ago - I was called to dinner and left this reply un-posted! 

In my Amateur Radio days, I often encountered pseudo PL259s and SO 239s of Far Eastern origin.  Their threads were 5/8" by 1 mm pitch, their bodies were die-cast from zinc alloy and plated.  I think the insulators were recycled washing-up bowls! 

Sometimes they would cross-mate with 'proper' PL259s and SO 239s and sometimes they wouldn't!

Fortunately, from dismantling many items from the war surplus market, I had built up a good stock of genuine Amphenol UHF connectors, real brass, silver-plated all over and with insulators of mica-loaded Bakelite. 
Best regards,

Pete W.

If you can keep your head when all about you are losing theirs, you haven't seen the latest design change-note!

Offline Chuck in E. TN

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Re: 1" x 20 tpi conduit thread ????
« Reply #6 on: January 28, 2014, 02:40:16 PM »
For what it's worth, I grew up in the New York town where that Amphenol connector was made. My mother and father retired from that plsnt, and my youngest brother still works there.
I am also retired USAF and installed/repaired many of those connectors on aircraft, including safety wireing them.
Chuck
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Offline 75Plus

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Re: 1" x 20 tpi conduit thread ????
« Reply #7 on: January 28, 2014, 06:26:50 PM »

I've just done a search for 'Amphenol SO239' and the best data sheet I found quotes 5/8" by 24 tpi UNEF.
 
Hi Pete I stand corrected. I was trusting a 79 YO memory and I have found that it can be dangerous.  :doh: I just went to the shop and looked at the tap and die that I have had in this thread for well over 20 years. 5/8-24 UNEF. One would think the specs would be burned into my brain as the info was laser ed into the tools!!


Offline awemawson

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Re: 1" x 20 tpi conduit thread ????
« Reply #8 on: January 29, 2014, 11:31:53 AM »
This is what the original question was all about:

A/ Amphenol don't make a converter to fix flexible conduit to the rear of these connectors
Andrew Mawson
East Sussex

Offline awemawson

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Re: 1" x 20 tpi conduit thread ????
« Reply #9 on: January 29, 2014, 11:32:42 AM »
B/ Andrew Mawson does  :ddb:
Andrew Mawson
East Sussex

Offline awemawson

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Re: 1" x 20 tpi conduit thread ????
« Reply #10 on: January 29, 2014, 11:34:13 AM »
C: Resulting in Adaptaflex conduit fixed securely to Amphenol connector  :lol:

Andrew
Andrew Mawson
East Sussex

Offline Pete W.

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Re: 1" x 20 tpi conduit thread ????
« Reply #11 on: January 29, 2014, 11:53:22 AM »
Hi there, Andrew,

It looks like you've achieved a good result there.

I apologise for my digression. 
Best regards,

Pete W.

If you can keep your head when all about you are losing theirs, you haven't seen the latest design change-note!

Offline awemawson

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Re: 1" x 20 tpi conduit thread ????
« Reply #12 on: January 29, 2014, 11:56:48 AM »
Pete,

 no apology needed, the offshoots of some of these threads (intended pun) are often more interesting than the original question  :lol:
Andrew Mawson
East Sussex