UNJ & UNS thread and gage

[unp1]

Dear Forum Members,

* We have Al die casting parts with "4 11/16 - 8 UNJ-2A" external threads. We have "4 11/16 - 8 UNS-2A" go / nogo gages and want to know if these gages would give us correct results.

* I found on the web that a UNS nut won't fit on a UNJ external thread (due to external thread root radius issue) but my question is about UNS ring gage on UNJ external thread.

I appreciate all responses in advance.

Thanks,
unp

 

[desertfox]

Hi

This site you should be able to get the answer

http://www.ring-plug-thread-gages.com/ti-UNJ-vs-UN.htm

 

[unp1]

Hi desertfox,

I appreciate your response. I checked the link but could not find detailed that I am looking for.

I am looking for the thread profile and dimension info. Does anyone think I might find this info in Machinery's Handbook?

Thanks,
unp

 

[desertfox]

Hi unp

I thought this answered your question on ring gauges below is an extract from the link I gave you, according to the passage below the UN ring gauge will reject the UNJ thread

SCREW THREAD RING GAGES
Because of the large root radius on the minor diameter of the external thread, the UNJ GO ring gage is supplied with an enlarged minor designed to clear the root radius. The GO ring gage is the only gage that is modified specifically for the UNJ specification and the only difference between the UNJ GO and the UN GO thread gages is the minor diameter. The UN GO ring gage if used to measure the UNJ thread the gage will reject the part because of the minor diameter interference. The UNJ NOGO ring gage is identical to the UN NOGO ring gage except that it may be marked with a "J". The minor diameter of the NOGO ring gage is relieved to just below the pitch diameter, and because of this the standard UN NOGO gage will clear the minor diameter of both the UN and UNJ external threads.

 

[KENAT]

Maybe, although my 27th edition has only a brief mention of UNJ. You may be better looking at the actual ASME B1.15 standard.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[unp1]

I appreciate all responses.

Thanks, unp