Your 1 29/32 (1.906) does not appear to be a standard thread size.  Neither does the 24 pitch match the bolt size.  I have not run across any UNS-3A standards.  Everything about this is strange unless it may be a soft converted metric?

You might go to www.boltscience.com and ask them.  Mr. Eccles has many tables on his web site that you might find something close.

Bill P.
CSFT, Inc.

All UN, UNS, UNEF, etc are all 60 degree.

UNS means that the thread dimensions are calculated according to ANSI/ASME B1.1 Section 5 and 8, but the designer is supposed to call out the Major Diameter, Pitch Diameter and Minor Diameter since the engagement is a factor in the answer since as the engagement increases, the tolerances loosen.  As a result of all of this with the fine threads, minor variations from the required dimensions may have a major impact on strength, and reverse engineering is potentially dangerous.  Also plating must be considered properly.  With those warnings out of the way the dims are:

Major   1.9062 / 1.8990

Pitch   1.8792 / 1,8764

Minor   1.8494 Min (Max is ref only .18611)

Pitch and minor diameter are reduced as follows:
Engagement  Change
1/4"        .0006
1/2"        .0008
1"          .0011
 or .001125 x sqrt(engagement (in))

Looking for the diameter of metric taptite screws?