What is this thread called these days? 3/4″-16 SAE

[Kevin MurrellParticipant @kevinmurrell62078]

In other words, what search term ought I to use to find a suitable tap – in all the suppliers.

Thanks

[Kevin MurrellParticipant @kevinmurrell62078]

[StueeeeParticipant @stueeee]

If it's SAE, it would normally have a 60º thread angle, so would be 3/4" x 16 UNS (Unified Special) or possibly UNEF (Unified Extra Fine)

[Clive FosterParticipant @clivefoster55965]

For all practical purposes in the UK 3/4 x 16 UNF is the same thread.

Theoretically there can be small differences in the specifications, particularly if its old, but nothing that will matter to the fit of ordinary threads.

Clive

[Keith LongParticipant @keithlong89920]

You've already got the search term,"3/4" – 16 SAE" followed by "tap" works for me. You could always try 3/4" UNF.

[Kevin MurrellParticipant @kevinmurrell62078]

Thanks all. TraceyTools came up trumps.

Edited By Kevin Murrell on 22/10/2019 15:36:59

[John ReeseParticipant @johnreese12848]

I believe the SAE callout was abandoned many years ago and replaced by UNF.

[old martParticipant @oldmart]

Also threads marked NF are now UNF.

[Bill Davies 2Participant @billdavies2]

I was taught that UNC and UNF were replacing (or had replaced) BSW and BSF in the British motor industry, and would be adopted by the rest of the mechanical engineering industries. That was in 1968.

It was a common standard agreed between USA, UK and Canada after the Second World War. Wikipedia says that the system was adopted in 1948.

Wikipedia – Unified threads adopted

[Nicholas FarrParticipant @nicholasfarr14254]

Posted by old mart on 22/10/2019 16:54:07:

Also threads marked NF are now UNF.

Hi, but with the exception of 1"

The one on the left is 1" x 14 NF and the one on the right is 1" x 12 UNF.

Regards Nick.

[old martParticipant @oldmart]

Thee were some changes made when UNF was ratified, that 12/14 tpi was exactly where the change took place. UNF threads from 1" upwards are now fixed at 12tpi, unless they are UNS, which could be anything.

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