Author Topic: 1" x 20 tpi conduit thread ????  (Read 5135 times)

Online awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 6939
  • Country: gb
  • East Sussex, UK
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

  • Hero Member
  • *****
  • Posts: 624
  • Country: us
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

Online awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 6939
  • Country: gb
  • East Sussex, UK
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.

  • Hero Member
  • *****
  • Posts: 809
  • Country: gb
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.

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

Offline 75Plus

  • Hero Member
  • *****
  • Posts: 624
  • Country: us
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.

  • Hero Member
  • *****
  • Posts: 809
  • Country: gb
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

  • Hero Member
  • *****
  • Posts: 568
  • Country: us
  • USAF Retired
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
Chuck in E. TN
Famous TN last words: "Hey ya'll, watch this..."
MicroMark 7x14, HF X2 mill, Green 4x6 saw. Harbor Freight 170A mig

Offline 75Plus

  • Hero Member
  • *****
  • Posts: 624
  • Country: us
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!!


Online awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 6939
  • Country: gb
  • East Sussex, UK
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

Online awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 6939
  • Country: gb
  • East Sussex, UK
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

Online awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 6939
  • Country: gb
  • East Sussex, UK
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.

  • Hero Member
  • *****
  • Posts: 809
  • Country: gb
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!

Online awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 6939
  • Country: gb
  • East Sussex, UK
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