Can anyone recognise this thread?

[GreensandsParticipant @greensands]

Does any recognise the thread as machined on a pair of Juliet X-Head pins which mic up as 3/16x36tpi? The drawing for the item calls for a 5/32×40 or a 3BA thread but it does not conform to either of these standard sizes.

[JasonBModerator @jasonb]

How sure are you of the tpi? as 2BA is only a couple of thou less than 3/16″ at 0.185″ but coarser at 31.4tpi

There is also #10-36 UNEF which is the right tpi but 0.190″ dia

[Charles LamontParticipant @charleslamont71117]

Pedantry corner: #10-36 seems to be UNS, S for Special, not UNEF which apparently only goes as small as #12-32.

[JasonBModerator @jasonb]

Quite right charles.

[GreensandsParticipant @greensands]

I can’t belive that it us anything as exotic as a UN/UNF thread form but at the moment I have yet to come up with an answer. 2BA and 10-32 are close on diameter and make a partial entry into to the corresponding  tapped hole but are not right on TPI which unaccountably records a pretty good fit at 36 on my thread gauge.

[Michael GilliganParticipant @michaelgilligan61133]

A look at the thread form should readily distinguish between BA and UN

Get the Loupe out
MichaelG.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi. apart from what has been said, the only thing I can find is ANF 8 36TPI, but that is just under 11/64″, Maybe someone just screw-cut the threads that you have, but of course they would have done the nuts as well.

Regards Nick.

[noel shelleyParticipant @noelshelley55608]

4.5mm X .75mm ?    0.177″ X approx 34tpi . Worth a try ? Noel.

[GreensandsParticipant @greensands]

I have decided to cut my losses and drill out the X-Head to receive a newly made pin threaded 3BA. Thanks for all the help offered.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Greensands, that seems like a good plan to me.

Regards Nick.

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