Help identifying thread

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

Most likely 8-32

Tony

poss UNF does that help.

Try:-

ANF ( 60* ) #10 = 32TPI

2 BA = 4.0 mm / 0.1575

George.

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

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

Tony

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

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

Andrew

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

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

#10-32 UNF is .190" diameter

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

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

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

[This posting has been removed]

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

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

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.

[This posting has been removed]

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.

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