【转帖】0, 0000 thread specs

yang686526

#00, 000, 0000 thread specs
a while back i posted
when i have thread questions i check one of three places....machinery's handbook, mil-s-8879 & mil-s-7742.  the machinery's handbook has some good information on miniature screw threads.
heckler   
sr. mechanical engineer
      o
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this post contains no political overtones or undertones for that matter and in no way represents the poster's political agenda.
thanks heckler, i'd looked in machineries.  they don't appear to have them.  i'm not familiar with the other 2 specs.
these are not unm (unified miniature) threads.
they are a legacy of the american national thread form and should have generally been replaced by unm but are still in use.
someone gave me an extract of b18.6.3 since i posted and it does have the information with an opening paragraph saying:
quote:
the following dimensional data for the no.0000, no. 000, and no. 00 thread sizes is provided in table v-1 for convenient reference until such time as these thread sizes may be adequately documented in an appropriate standard relating specifically to screw threads.
so unless someone knows better for now i'll reference b18.6.3.
kenat, probably the least qualified checker you'll ever meet...
i have access to b18.6.2-2002
its statement of scope begins with:
quote:
this standard is intended to cover the complete general and dimensional data for the various types of slotted and recessed head machine screws and machine screw nuts...
i cannot find a table v-1 in it.
there is a paragraph that states:
quote:
the threads on machine screws, exceptfff"> for the no. 0000, no. 000 and no. 00 sizes, which are covered in table 19, shall be unified standard, class 2a...
table 19 provides some basic dimensions for the threads.  pitch, limits on major and pitch diameters and the nominal minor diameter (external) or major diameter (internal).
it does not fully define the thread form in the level of detail that b1.1 does
asme  b18.6.3-2003 is what i have an excerpt from, not 18.6.2.
the extract i'm looking at is i believe appendix v.  table v1 gives the major, minor & pitch diamters with tolerances, sounds like similar to your table 19.  it shows that they should be called out as "ns" for the series designation which was part of my original question in my original post.
i agree it doesn't fully define the form to the extent that b1.1 does but it's the best i've found in a current standard.   
kenat, probably the least qualified checker you'll ever meet...
sorry, typo.
the above from b18.6.3-2002
i wondered.
still the best i've found so far though.
kenat, probably the least qualified checker you'll ever meet...