Help identifying thread

[Chris SheltonParticipant @chrisshelton11794]

Hi I have a thread on an American made car diagnostic probe, which I am having trouble identifying, the major diameter is 4mm or .1580" it is 32tpi. can anyone help, I need to purchase a tap to suit, have looked on the internet, but cannot match the details.

Thank you

[Chris SheltonParticipant @chrisshelton11794]

[Tony Pratt 1Participant @tonypratt1]

Most likely 8-32

Tony

[Marischal EllisParticipant @marischalellis28661]

poss UNF does that help.

[mechman48Participant @mechman48]

Try:-

ANF ( 60* ) #10 = 32TPI

2 BA = 4.0 mm / 0.1575

George.

[Chris SheltonParticipant @chrisshelton11794]

Hi, Thank you for the replies, just found my engineers Black Book, and it looks as if it could be 5/32 BSW, which is not listed in Zeus

[Tony Pratt 1Participant @tonypratt1]

Hi Chris, 2 points, the yanks would not use BSW & .158" is bigger than 5/32" that being said it will work.

Tony

[Clive Brown 1Participant @clivebrown1]

5/32" BSW is Meccano thread. Seems unlikely on an American gadget.

[Anonymous]

Given it's US made I'd bet it's 8-32 UNC.

Andrew

[Howard LewisParticipant @howardlewis46836]

Zeus Charts give 6-32 ANC as having an OD of 0.138", and 8-32 as 0.164" The thread form will be 60 degrees

There is no ANF thread with 32 tpi pitch.

It could be 10-32 UNF which is 0.164" diameter, but slightly truncated to give the 0.158" OD.

If it were 4mm it would be 0.15748" diameter, but M4 is 0.7mm pitch which is 17.78 tpi.

HTH

Howard

[Jeff DaymanParticipant @jeffdayman43397]

Howard Lewis – your third sentence – #10-32 UNF is NOT .164" diameter, #8-32 UNC is .164" diameter

#10-32 UNF is .190" diameter

[Howard LewisParticipant @howardlewis46836]

Quite RIGHT,

I misread from one line to the next

Sackcloth and Ashes again!

So looks like 8-32 UNC as a likely candidate.

Howard

[Chris SheltonParticipant @chrisshelton11794]

Thank you all for taking the time to reply, I have ordered a 5/32 BSW set of taps, as Tony P said it will work.

[Tony Pratt 1Participant @tonypratt1]

Posted by Chris Shelton on 16/05/2020 13:24:56:

Thank you all for taking the time to reply, I have ordered a 5/32 BSW set of taps, as Tony P said it will work.

If it doesn't work I will refund your money or send you an 8-32 tap.

Tony

Edited By Tony Pratt 1 on 16/05/2020 13:49:57

[Pete RimmerParticipant @peterimmer30576]

Posted by Howard Lewis on 16/05/2020 12:55:37:

Zeus Charts give 6-32 ANC as having an OD of 0.138", and 8-32 as 0.164" The thread form will be 60 degrees

There is no ANF thread with 32 tpi pitch.

It could be 10-32 UNF which is 0.164" diameter, but slightly truncated to give the 0.158" OD.

If it were 4mm it would be 0.15748" diameter, but M4 is 0.7mm pitch which is 17.78 tpi.

HTH

Howard

Sorry to be a correction-ist Howard but I think you multiplied instead of dividing there. 0.7mm pitch would be 36.28tpi

[Former MemberParticipant @formermember32069]

[This posting has been removed]

[Neil WyattModerator @neilwyatt]

This is a great explanation of the different systems from an American perspective.

http://www.rustmag.com/gear/2018/1/4/threads-and-thread-systems

With one exception UNC and Whitworth are the same, except for the flank angles.

Neil

<edit> I forgot the link!

Edited By Neil Wyatt on 16/05/2020 15:15:59

[Chris SheltonParticipant @chrisshelton11794]

A local friend came to my rescue with a 5/32 BSW tap, after tapping the part it screwed onto the probe about half a turn, so have now ordered, an 8-32 tap, can someone tell me what the 8 in the 8-32 stands for?

Tony I will not hold you to your promise of a refund, after all I could tap some Meccano parts now.

[Former MemberParticipant @formermember32069]

[This posting has been removed]

[JasonBModerator @jasonb]

below 1/4" dia UNC & UNF use a number system a bit like old wood screws and BA threads, the higher the number the larger the thread.

[Tony Pratt 1Participant @tonypratt1]

Posted by Chris Shelton on 16/05/2020 17:23:33:

A local friend came to my rescue with a 5/32 BSW tap, after tapping the part it screwed onto the probe about half a turn, so have now ordered, an 8-32 tap, can someone tell me what the 8 in the 8-32 stands for?

Tony I will not hold you to your promise of a refund, after all I could tap some Meccano parts now.

Thanks, let us know if the 8-32 does the trick, 5/32 BSW is slightly smaller on diameter, maybe that is the problem.

Tony

[Chris SheltonParticipant @chrisshelton11794]

Thank you Jason for the explanation, and Tony P will let you know the outcome when my tap arrives at the end of next week.

[Chris SheltonParticipant @chrisshelton11794]

Thank you,

To all who took the time to answer this query, 8-36 tap arrived today, and the threads do match.

 

 

Edited By Chris Shelton on 20/05/2020 14:41:00

[Tony Pratt 1Participant @tonypratt1]

Posted by Chris Shelton on 20/05/2020 14:40:41:

Thank you,

To all who took the time to answer this query, 8-36 tap arrived today, and the threads do match.

Edited By Chris Shelton on 20/05/2020 14:41:00

Wasn't it 8-32?

Tony

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