huangyhg

1.125 -13unja pitch diameter
i need to find this information
check out our whitepaper library.
the standard thread form for 1-1/16" is 8 unc or 12 unf.
the 13 unj thread form data can be found in the machinery handbook, in the 25ed pp1638 table 1 or mil-hdbk-28
as alluded to by boo1, this thread callout appears fundamentally flawed on multiple fronts.
"a' in a thread callout usually indicates an external thread (with "b" designating internal), but is used in conjunction with a tolerance "class" number:
"1.125-12 unjf-3a"
your callout doesn't include a tolerance class, which you must know to determine the pitch diameter limit dimensions.
the "j" thread form is a modified thread form (from the "un" and "unr" thread form defined in asme b1.1) with a controlled, tangent root radius on the external thread, and an increased minor diameter on external and internal threads. it is usually specified in fatigue critical applications.
just looked at my machinery's at home and it's the 22nd edition, not the 25th...
amerianan standard unified inch screw thread form data
tpi 13
pitch=0.07692
depth of sharp v-thread 0.06662
depth of int trd and un ext trd 0.04164
depth of unr ext thd 0.04580
truncation of ext thd root 0.01655
truncation of unr ext trd root 0.01249
truncation of ext trd crest 0.00833
truncation of int trd root 0.00833
truncation of int thd crest 0.01665
flat at ext thd crest and int thd root 0.00962
basic flat at int trdn crest 0.01923
max ext trd root radius 0.01110
addendun of ext thd 0.02498
my confusion, boo1. in your original post, i thought you were referring to (and i was looking for in my machinery's handbook) either:
1) information specific to the "unj" thread form, or,
2) tabulated information (pitch diameter limits, etc.) for this specific diameter / thread pitch combination of any "unified" thread form.
i did not realize you were referring to the "basic" or "nominal" thread profile data used to calculate those dimensions.
while some of the basic thread profile dimensions in your post are shared with the unj thread form, the modifications made to the "un" thread form to create the "unj" thread form mean some of them are not (example: depth of internal and external thread, truncation of external thread root, basic flat at external thread crest, external thread root radius limits).
as stated in my original post, were this truly a 1.125-13 unjs thread, the dimensions should be calculated per the applicable specification (table viii for mil-s-8879). the "basic thread (profile) data" used in those calculations should also be specific to the unj thread form (table 1, pages 16 and 17, of mil-s-8879 for threads per mil-s-8879).
that would be a very odd thread size though.
absolutely.

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