What sort of thread is 1/4- 32UNS -2A?

[Steve WithnellParticipant @stevewithnell34426]

Is this normally referred to as 1/4 – 32 UNEF?

2A appears to be the thread tolerance.

Steve

[Steve WithnellParticipant @stevewithnell34426]

[Tony BrazierParticipant @tonybrazier31255]

Hi that the same as glow plug thread for glow engines.

Tony

[Enough!Participant @enough]

UN standards are:

UNC – coarse
UNF – fine
UNEF – extra fine
UNS – special (pitches not covered by the other categories)
UNR – must have root radius

1/4 – 32 is specified in the UNEF category. I don't know why it would be described as UNS.

Thread classes are 1A/2A/3A and 1B/2B/3B the number being the fit (1=loose to 3=close). A is used for external threads; B for internal

[Steve WithnellParticipant @stevewithnell34426]

Posted by Tony Brazier on 17/05/2015 22:36:47:

Hi that the same as glow plug thread for glow engines.

Tony

Thanks for that – I must have one in the box then!

Steve

[Steve WithnellParticipant @stevewithnell34426]

Hmm the nuts that I have which are specified as 1/4- 32UNS -2A, don't fit the enya glow plugs I have. The pitch is off just enough so the nuts don't run on to the plug thread. Don't worry, I'm not intending to fit nuts to my plugs, it was just an easy way to test Tony's point above.

Steve

[Author]

Posts