A little extra:
Class 1 Loose Fit
Class 2 Free Fit
Class 3 Medium Fit
Class 4 Close Fit
The "A" and "B" denote male and female threads, respectively.
UNF and UNC (coarse) threads have rounded crowns and roots (peaks and
valleys).
NF and NC threads are the original American National standard.  They have
flattened crowns and roots.
They will work interchangeably with their Unified Thread Series partners.

Pity the design youngster that comes around here with an "A" callout on a
hole thread.  Who wants to hear a one hour thread lecture?

> Larry Jindra
> TRW/Avionics Systems Division
> mailto:[log in to unmask]
> ph (619) 592-3424
fax(619) 592-3940
...


-----Original Message-----
From: Keel, Mike [mailto:[log in to unmask]]
Sent: Tuesday, June 15, 1999 11:17 AM
To: [log in to unmask]
Subject: Re: [TN] Fab: Tap and die callouts


Hello World

Stand by for News . . .

American Standard Bt.1-1949 was the first American standard to cover those
Unified Thread Series agreed upon by the United Kingdom, Canada, and the
United States to obtain screw thread interchangeability among these three
nations.


These Unified Threads are now the basic American standard for fastening
types of screw threads.


UNF -  fine thread series, this series is suitable for for production of
bolts, screws,
           and nuts and for other applications where Course series thread is
not applicable.


Thread Classes  -  Thread classes are distinguished from each other by the
amounts of tolerance and allowance.
                             2A and 2B -  are most commonly used for general
applications.



M Keel
San Diego


 ----Original Message-----
From: Ed Cosper [mailto:[log in to unmask]]
Sent: Tuesday, June 15, 1999 6:53 PM
To: [log in to unmask]
Subject: [TN] Fab: Tap and die callouts


Hi all,

I hate to display my ignorance but I need to know what  #10-32 UNF-2B thru
means. I understand it is a treading requirement with a 10-32 tap but I dont
know what "UNF-2b thru"means.

Thanks

Ed Cosper

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